2 STROKE WORLD .net

A little history on the project, my father built this car from '72 to '74. It was successfully given a log book and SCCA homologation to compete in the D-Sports Racer category. This chassis predated the modern steel roll cage rules, meaning an all aluminum (crash structure) construction was allowed, including the crash structures. Additionally, there was no minimum weight prescribed for cars under 850cc. The car is basically an aluminum monocoque, or maybe better described as a semi-monocoque as it uses effectively an aluminum tube frame with riveted and bonded panels. At the time of build the Suzuki GT750 was a popular engine, and given a proper tune could make over 100hp easily. The first engine build was performed by Eric Buell, this was back when he still lived in Pittsburgh. Later builds were performed by my father, and the engine evolved somewhat over time. The chassis was engineered by my father's friend, who at the time was a full time engineer at GM. My father constructed the car with the help of another friend and his wife. The car was raced from '74 to '79 with mediocre success and then mothballed. They participated at Nelson Ledges, Summit Point, and Mid Ohio, but with a limited budget and limited man power they never quite got it going like they had hoped. The car remained in the garage unused for 40 years. It had become such a burden on space that my father eventually mounted the car on the wall, it stayed there for something like 16 years.

Here's a bit of photo history of the car.
(https://i.imgur.com/Fw5tmis.png)
(https://i.imgur.com/lYElTNI.png)
(https://i.imgur.com/8yh88Yk.png)
(https://i.imgur.com/sUGU42e.png)
(https://i.imgur.com/zLsC2xU.png)
(https://i.imgur.com/7LYW02V.png)
(https://i.imgur.com/sOrLeMi.png)
(https://i.imgur.com/Be03qJo.png)
(https://i.imgur.com/0WNPskw.png)
(https://i.imgur.com/EO96b3h.jpg)

Here's the car as we were pulling it off the wall, I want to say this was in 2015, maybe 2016. It's hard to recall.

(https://i.imgur.com/MxZJ4io.jpg)
(https://i.imgur.com/rZK6XaM.jpg)
(https://i.imgur.com/3VzIgUQ.jpg)

Once off the wall we put the car back on the fabrication table that it had sat on for something like 20 years before. The process began. The all aluminum crash structure simple wasn't adequate. After 40 years of competition in other areas of racing my father had learned a lot from the days when he built the car. So he took the chance to update and change a number of items, but tried to be sensitive to keep the original spirit of the car. The focus was mostly on engineering issues, especially those that could be a safety concern.

(https://i.imgur.com/JuxsfR4.jpg)
(https://i.imgur.com/g8639nU.jpg)
(https://i.imgur.com/g8639nU.jpg)
Progress
(https://i.imgur.com/oi50Lsk.jpg)
(https://i.imgur.com/pALBQWx.jpg)
(https://i.imgur.com/9JODcIB.jpg)
(https://i.imgur.com/SNHgrjn.jpg)

And, this last weekend we got to the track and managed to race the car. We fought with the master cylinders right up until the race, but managed decent brakes come race time. Then of course the car overheated. But I managed the best laps of the weekend in the race, so for having basically used the race weekend for testing it was a positive result. We simultaneously got the car on track for it's 40th anniversary of retirement, and my 25th anniversary of race driving competition. A true success!

(https://i.imgur.com/bgfPSiH.jpg)
https://youtu.be/pH5OCOBPmZg

I have other pictures as well. I can also publish more detailed specs if anybody is interested. We plan to continue development of the car. It actually fits the rules for the modern P2 class which is sort of the modern equivalent of D-Sports Racing. So we could compete in national competition if we wanted, of course the car wouldn't be competitive, but it would be fun.

Fantastic some specs on the engine . love how the chambers look like they made von a brake .

SUPER COOL !!!

that's a real blast from the past
its great that you have so many pics from way back.

nostalgic!!!
good luck with racing this beauty again

Great read , thanks for posting.

Man that is just cool.

Quote from: Cobraace2 on July 22, 2019, 09:14:18 PM
Fantastic some specs on the engine . love how the chambers look like they made von a brake .

The engine has the cylinder raised .04" as I recall. The cylinder was then decked, as was the head. The head was welded up, the spark plugs were moved into the center of each chamber, and then the domes were reshaped. In the current form, the heads are just a circular shape without a proper squish band. This is the head as it was built 40 years ago. The ports are drastically changed, and the engine runs three VM38's using an adapter plate on the intake side of the head. The engine would willingly rev well past red line, which was an issue, because I've never driven a motor that was so willing to do so. It easily would pull to 10k plus. As a result, it got over revved several times last weekend, we haven't had a chance to tear it down, but we hope it wasn't hurt.

We have plans to redo the head though, as we have several, all it will take is welding it up and machining it. We already did all the setup work to do the machining, we just didn't have the time to weld a head up. Here's the model I made, I matched the head volume to the current volume, but we have added a squish band and slight toroidal chamber.


(https://i.imgur.com/sIEtapy.jpg)


Thanks, all for your enthusiasm. It's been a labor of love for my father especially. There are a lot of details to go through, as a result I'm confident we will be a lot more competitive in our next outing. The unofficial goal is to reset the all time lap record around the Schenely park circuit, it might take a year or two but I think we will get it.

Great history. Kudo's to your pop for keeping it and good luck with the record attempt !

Very cool story.  Very cool car.  I bet it's a GAS to drive!

I've heard about the Ocelot- what exactly was it? Love the car BTW!  :righteous:

Great car and story.

Quote from: gwcrim on September 25, 2019, 07:54:54 PM
Very cool story.  Very cool car.  I bet it's a GAS to drive!

It works rather well, once we iron out the bugs and I can drive it in anger, it should be a bit faster than a Formula Ford (if you're familiar).

Quote from: Evans Ward on September 28, 2019, 08:21:27 PM
I've heard about the Ocelot- what exactly was it? Love the car BTW!  :righteous:

This actually competed against the Ocelots. Basically in the D-Sport Racer" category at the time there were two displacement levels. One, I beleive 800cc set a minumum weight, it was something like 1000lbs. If you were under 800cc, then you could be as light as you wanted. My father chose that option. So he started with the 750 water buffalo and built a chassis around it. The Ocelots did the same, though they were much more successful than my father's operation.

Quote from: RDFL on September 28, 2019, 11:07:40 PM

Great car and story.

Thanks! It's great fun being able to campaign the car with my father some 40 years after he built it and after 25 years of driving myself. I visted my father last night and are scheming for 2020. Lot's of solid stuff in the works.

Also, that wood block that's holding up the rear sub frame in the second picture is still in my father's shop. He still uses it in the same manner. It's just a lot smaller and more burnt, worn, and abused than it was 40 years ago.

Anything updates during the off season for this Water Buffalo powered race car?

Yes actually. I was just looking at the car with my dad last week.

We got the new AP floating pull masters in, both new for front and rear brakes. My dad also got a nice new balance bar TIG'ed up. Looking good! I'll grab some photos the next time I'm up there. We also got a larger master for the clutch, and my father has gone through the clutch and is adding a high performance clutch pack and springs from Barnett. Hopefully the slipping issues go away.

I finally got my dad talked into welding up one of our spare heads and milling it completely, spark plug holes and all. And we are going to do a new base gasket, the current one obstructs the ports a tad and is in rough shape. The engine is apart right now. We are working on the sheared water pump drive, we haven't decided on a direction for that. Maybe electric, maybe aftermarket gears.

From there it's going to be minor stuff. Some stays for various body panels, double check all the suspension bits, scales, alignment. We hope to do four or five weekend this year and really hand it to the geezers on vintage circuits.

Also my boy is four, so I'm looking at some karting for him this year. So it should be a busy season.

We fought a bit with the water pump gear. Basically, they don't like the RPM we turn and they were junk in the first place. There's a nice press on steel gear in the UK, but after shipping, parts, return shipping, the price is a little silly. Something near $200 all said and done. We are married to the mechanical water pump and adapted a high flow impeller and housing. We've decided against an electric pump as we don't want to carry the extra amp hours. We run total loss, and the battery is way too heavy as is. So i'm going to cut one of these guys out aluminum, but since it will be milled instead of hobbed, we expect it to self clearance a bit. It should work fine, we'll just flush the transmission once after some stand time. I may also cut a sleeve to press over the plastic gears shoulder which should make the plastic gear more reliable, but it will likely stay in the parts bin. After all, spare parts are never used.

(https://i.imgur.com/jEDDTa3.jpg)

We decided against the above hubbed design and instead are going for this hub-less setup. The existing G750 steel hub that's in all the plastic water pump gears will be shrink fit to the new aluminum gear. The benefit of this system is that the the gear will be removable without splitting the cases. All the other gear replacements that I've seen require the cases are split to change/remove the gear. It will be easier to machine too.

(https://i.imgur.com/WVIOujW.png)

We've also picked over our data from the single race weekend and have realized we were geared too short. Top speed was calculated to 107mph. We managed 109mph, it really likes to rev. So we are going a bit longer, it shouldn't hurt us in the slowest corners as we were too short there too. I machined the new sprockets today, looking good! It's basically free speed, we will just plain go faster. I also found in the data that I lost major time in the brake zones, I already knew this as the driver, but the decel curves were frankly pathetic. On a 20 turn course with stone walls the brake zones are pretty important. The new masters are going to be a huge gain.

https://www.pvgp.org/schenley-circuit-map/

I let the mill run through the night last night. .0625" end mill with a .0625" step down, .001" step over, at just 1.5 inches per minute. Run time was about 5 hours, more than 4 hours to just cut the teeth... I'll face the back side off tonight and then shrink fit the hub. If it works, I'll probably make as second one, there are a couple of small things that could be improved, but not bad for a first try. It's a good thing machine time is basically free.

(https://i.imgur.com/fnHVSJd.jpg)

(https://i.imgur.com/UjAXs2M.jpg)

Finished this one up as planned. Looking good!

(https://i.imgur.com/zVlpzk0.jpg)

(https://i.imgur.com/51vhgUo.jpg)

Excellent craftsmanship there! On the original nylon one in your pic, you can see the cracks as it is common and I've never seen a used one that didn't have one or more cracks. When that gear breaks, you lose your tach but more importantly your water pump circulation. This one broke on me 2 yrs ago 60 miles from home. I rode it back gingerly taking it down and pulling the head to see if warpage occurred. It was straight and not warped as Suzuki really over engineered those triples.

Here's a new Suz nylon one for comparison:

We actually bought a new one, only to have it be cracked upon arrival. And our gear broke mid race, leaving me to retire.

We have seen 10k on the tach, which is the danger zone big time. The plastic gears just never stood a chance.

My father has the engine mostly back together. Says the gear will be perfect. Obviously we need to run it, but there are no obvious issues upfront.

He bought a new impeller and housing from the UK, the impeller is missing the key slots. We aren't sure how to make it work yet. I might end up scraping a keyway for it on the mill, that will be a new one...

early style used a woodfruf key and later ones just used a roll pin.  A lot of impellers have a deep slot plus keyway so they will fit wither design of shaft.

I may have a water pump shaft I could swap for yours.  If you need one, please let me know and I'll check my spares box.

My father ended up fixing the impeller with a scroll saw and some files, he just added the keyway. It has a bit of lash but it will be just fine. He spoke with BDK and they mentioned the old/new situation.

I machined up a bracket for the chain tensioner today. I'd post pictures but without context it's not really worth seeing. Suffice it to say, since the drive train is fixed and the engine is fixed there's a third sprocket that's mounted on eccentrics, the eccentrics are used to adjust the third sprockets location to control chain tension. The bracket was too flimsy before, there is an amazing amount of load on it. We should be good now.

The best news is that my father delivered the head to me today. It's all welded up and ready for machining. I've got the model all worked out. I have the game plan for setting up the head on the mill. Unfortunately my power drawbar is acting up. I might go ahead and do it with manual tool changes, but it's such a bummer running the machine like that. I've got to get some customer work straightened out then I'll make the decision on either fixing the PDB or going ahead with machining. The drawbar repair is like a two to three day affair and I need access to a lathe which is a bit of an issue currently.

(https://i.imgur.com/4gON1it.jpg)

The company that provided me with a day job shut down yesterday as a part of non-essential closures of businesses in PA. As a result I have a lot of free time. For my creative self, this is a win. We'll see how the financial self survives, but for the time being I am going to keep busy and enjoy the vacation.

So, last night I got the stock on the mill that will fixture the GT750 head for machining. For those who aren't familiar with machine tools, my mill is quite small. In fact, in the scheme of things it's basically a toy. Though I've spent a lot of time and effort to make it as capable as it is, and I manage great results on a number of projects. Keeping the size of the mill in mind, to place the 7" wide (tall in Z height) on the mill I had to remove my automatic tool changer. But, I got the stock squared up and looking good, luckily I just needed one tool to get the work done. Today I will be boring all the holes in the fixture plate, tapping said holes, and then surfacing the plate so that it's nice and parallel with my table. I've purchased Mic6 plate for the fixture, which should be fairly flat, but I want to get this right and have a nice repeatable fixture for future head reworking. Since the head will get worked over on both sides the fixture end up using the head bolt pattern and a flipped version of it. Of course the head itself will get surfaced on the fin side before further machining can be done, it's the only way to assure the head stays flat when the combustion chambers get machined. As of now, the combustion chamber cutting will take around 4 hours, luckily the machine runs itself and I don't have to pay any attention to it as it grinds away.

Short video of the stock getting cleaned up - https://i.imgur.com/btu3W2S.mp4

(https://i.imgur.com/Bgj0ESr.png)

Sorry to hear about the work but good to see you are staying busy.

Is your mill CNC, and can you do more complex combustion chamber shapes such as different squish band angles and diameters and even torroidal heads?

Yes, it is CNC. The head design is slightly torodial, though not particularly radical in that shape. I put a piston on the mill and measured the arc of the piston top and then matched the squish to be a mirror image of it. My father gave me figures on the design beyond that, mostly squish band width, and I then adjusted the shape of the combustion chamber to give us the volume we need.

But the sky is the limit, really just about any imaginable shape can be made. The nice thing is that no special tooling is required. The entire finishing operation will be done with a 1/4" ball end mill running really slow with really small stepover.

Here's a few photos from the process. The negative of the combustion chamber provides head volume.

(https://i.imgur.com/2nE7Uz2.png)

(https://i.imgur.com/TvgLhf5.png)

(https://i.imgur.com/hAQXha7.png)

Well I came down with Tonsillitis and that slowed me down a couple of days. On the mend now, tonsils are feeling so much better.

I got the fixture plate machined. Turns out somewhere along the line my model got out of scale and that resulted in the first set of holes not lining up with the head. So, I went back and redid all the CMM because I couldn't find my original data, then redrew all the models. The CAM was good, so the machining went smooth. Literally minutes of machining and everything came out awesome, of course I spent like two hours doing the CMM and at least two more hours redoing and verifying models. All seems great though.

(https://i.imgur.com/1Rvl8WS.jpg)

(https://i.imgur.com/aER3Gsf.jpg)

(https://i.imgur.com/Bw33o5t.jpg)

(https://i.imgur.com/Yz653d6.jpg)

What a ride that was. Now onto the head. Seeing as it's the first one to hit my mill I will be taking my time.

It's really important to get it right before you do my cylinder head.... :whistle:

Quote from: teazer on March 24, 2020, 12:10:56 PM
It's really important to get it right before you do my cylinder head.... :whistle:

Fingers crossed! Working on these GT750 heads is tricky because they all seem different. There's nothing to reference, especially so after they've been welded. But I think I have it worked out.

I grooved all the large (tube) bolt holes for snap rings. This means I can bolt the head to the fixture plate with zero protruding bolts or hardware. That makes facing the head (both sides) so much easier.

(https://i.imgur.com/Z3PxgNf.jpg)

(https://i.imgur.com/JcOM5DM.jpg)

(https://i.imgur.com/N4ufGxw.jpg)

I am now ready to face the top side. Once the top side is faced, the head will be flipped over and bolted back down. I will reference it, square it up as best as possible, then actually machine the combustion chambers and spark plug holes. The plan is to thread mill the spark plug holes, but I will be taking them a size large and using a steel insert in the head. To finish, the head will have to be flipped back over, and the spark plug holes will be faced for the crush washer surface, at the same time I will set the depth of the spark plugs. With the plug holes being welded up I figured it would just be easiest to do it at the end.

It needs a little deburring but it looks good!

(https://i.imgur.com/YfQK8YR.jpg)

Oh, and my father sent me this.

(https://i.imgur.com/cZ5rxgV.jpg)

Faced off the gasket surface, then roughed out the combustion chambers, and bored the spark plug holes. That weld is some sticky stuff. There's some minor porosity in the welds. My father struggled with a broken TIG torch before I convinced him to switch over the MIG machine. He suspected we'd get some porosity, but we also figure it won't matter much. If the head design seems successful we can always fill the porosity and machine them again.

(https://i.imgur.com/19vjY7d.jpg)

A video of surfacing. I just hand programmed this. I did it in two passes, the first at .02" depth, the second at .005" depth. I tossed the head on the surface plate after this and it's really good, better than I would have expected... I'll probably still lap it in a bit on the plate.

https://i.imgur.com/KDLpqqZ.mp4

Here's boring one of the spark plug holes. Pretty boring really...

https://i.imgur.com/5SOE7kg.mp4

There are only two operations on each combustion chamber left, but the run time will be around 3.5 hours to do those six operations. The first with small stepover using a ball end mill, this will still effectively be a roughing operation. This operation is needed to minimize tool load spikes for the final operation. The final operation will have an even smaller stepover, but will use a smaller ball end mill, and hopefully will produce a really clean and well finished surface. Fingers crossed, it's been a long road to get here. Let's not mess it up now!

Well, i'm not super happy. I messed up the programming on the second to last operation, I should have left more stock for the final op. That means the final operation didn't get it cleaned up as well as it should have been. Nothing a little emry cloth and some elbow grease won't fix, but not exactly the results I was hoping for. Not a major F up, it should work fine, just not the finish I wanted. Tomorrow I set the heights on the top side of the spark plug holes, thread the holes, then ream them, and install the steel inserts. The hard work is all but over now, it's down to the details. I'm pretty tired currently, luckily grandma took my son for the night. Gave my wife and I a much needed rest after the crazy 12 days or so.

I talked to my dad today, he's pretty bummed out about all the Covid fallout. He doesn't think we will see any races this year if this keeps up. Not much we can do but keep our heads down, prep the car, and hope for the best. That said, now that my current projects are slimming down, my wife's RD125 is next. The engine is coming out in the next week or so.

The images make the finish appear pretty bad, but in reality the cusps are hardly detectable with a finger nail. However, they should have come out mirror like had I gotten it all right. The next time I'll have it worked out...

(https://i.imgur.com/F8nYfOj.jpg)

(https://i.imgur.com/8KlSG2v.jpg)

This project is done for now. Spark plug sealing surfaces have been cleaned up, depth set. I milled the threads, but they will get steel inserts. I'm pretty happy overall with how this turned out. It's a great first try, on the second round it's only going to get better. Overall, this is the best head our GT750 engine has ever seen.

(https://i.imgur.com/qLMlY35.jpg)

(https://i.imgur.com/RUiSG7B.jpg)

My dad went through the motions of checking head volume, squish, etc.. Everything is looking good. The squish averages about .025" on all three cylinders. The motor will come back apart again and various items on the chassis will be checked over, but assembly for driving trim will begin soon. The new master cylinders are fully mounted with a new balance bar, the clutch cylinder has been revised, new clutch with Barnett discs and springs are in place. We should be able to run up through fifth gear without slipping the clutch from three on. And hopefully the car will be drivable in the pits too. I'm hoping to make a visits to my father's place this weekend, I'll try to grab some photos of the car.

The car is looking really good. The compression ratio came in right to 7:1, stock being 6.7:1. Perhaps a spot higher than we really wanted, but it may help the systemic over-rev we weren't pleased with. My father has picked over a number of the small details on the car, nothing major to report, but this is how racing machines work. If this lock down process continues (fingers crossed), I may start machining some of the more elaborate parts for the car. Currently it uses cast iron front upraights from a Triumph, that was common for the period. We can however update those. I'd also like to get some of the rear drive train on the lathe and lighten it up, maybe replace the cast steel seal carriers with billet aluminum bits, just generally shed some weight from the car. Almost all of the major weight that is easy to get rid of is unsprung weight, for a sub 1000lbs car that's a very important area of improvement. Especially so for rough tracks like the street circuits we generally compete on. Here are some photos. Keep in mind I'm posting 12mp photos, the ports look rough but in reality they are smooth as can be. I spent the rest of the time working on RD125 parts, I'll get photos of up for that project tomorrow.

(https://i.imgur.com/bbM6yX6.jpg)
(https://i.imgur.com/X9lhRQa.jpg)
(https://i.imgur.com/bsw1hI9.jpg)
(https://i.imgur.com/TLDW1DH.jpg)
(https://i.imgur.com/6yVMBb0.jpg)

The head is officially ready to go on. My father has been picking through a few other issues around the shop (valve job on his Mini Cooper S and stand alone ECU on his hot rod Mini), so the DSR has taken a bit of a back seat. He says he ironed out some timing irregularities he think existed, definitely small but perhaps troublesome. The new chain tensioner bracket that i mentioned machining on a few posts back is in, and it seems to be really nice and stout. Other than that, not much has changed.

(https://i.imgur.com/L5kgRYz.jpg)

It's all back together. My father modified the exhaust a bit, going to a larger ID perforated tube to the silencers. He also has the PI System (now owned by Cosworth) hooked up and is trying to calibrate the three EGT's. Keep in mind this data logger is something like 25 years old, we are running the software on a HP Windows 95 laptop from a 3.5" floppy disc haha. So while the data logger is certainly modern technology in relation to the car, we've done our best to run vintage data logging too.

It runs - https://i.imgur.com/YwRdZw2.mp4

(https://i.imgur.com/iXCwFLA.jpg)

Nice work on the waterpump gear & new combustion chambers, doing that sort of stuff is very satisfying
It's funny just how sticky weld material can become compared to the original base material, there must be a slightly different make up between the 2 materials. I have a head for my CZ400 that was welded & machined which has the same porosity issues as your head, never seemed to affect how it ran although when it turned up I was pretty unhappy after having seen the work done by the company on other heads
Did you end up correcting the slight misalignment between the cylinder bores & combustion chambers I've seen mentioned before? I assume because the whole combustion chamber was fully welded & you measured the top of the block to make your sub-plate that you would have been able to get the positioning exactly right

I think if my father had started with his MIG machine the porosity issues wouldn't exist. There was some issue with his TIG torch and he kept getting bad welds. The torch ultimately was replaced, but that was after he MIG'd the head basically problem free. Virtually all of the areas with porosity were touched by that broken TIG torch. Old dirty aluminum has proven tough to weld in general though. What also surprised me is how quickly the head naturally anodized. It was like 20 minutes at most after machining that it lost its shine. Whatever alloy these things are made of it doesn't react like any modern variants.

I got the head misalignment mostly corrected but it's not as good as i was hoping. Next time around I'll fix the head to the table, then bolt the cylinders to the head, then I'll use the touch probe to find the center of each cylinder. I'll set each cylinders center as its own work offset. The cylinder will get removed, then the program to machine the combustion chambers is run individually for each cylinder based on the real life spacing of the cylinders. This will assure that the combustion chamber is perfectly placed for each cylinder based of the cylinders themselves, also meaing the cylinder head is custom matched to each cylinder set and might not fit to other cylinders as precisely. What I tried to do was model the cylinders and reflect that onto the head model. Even after creating a dxf by touch probing the cylinder I never was able to get an accurate reflection back onto the head because there's simply nothing worth referencing on the head itself. I hope that description makes sense. Hind sight as they say is 20:20, and in the case of this head work I learned a ton. The carburetion has changed right off the bat, so something seems to have worked haha.

Today they announced the cancellation of the Pittsburgh Vintage Grand Prix. It always takes place in mid to late July. I suppose it's for the best but it certainly takes the edge off the last 9 months worth of preperation.

I was approached by a gentleman in Australia about my water pump gear. So I made him one and it came out pretty much perfect. The finish is exceptional.

(https://i.imgur.com/BCkaDMD.jpg)

That carb thread got me thinking about Lectrons so I got a hold of my buddy that offered us a set. It took him a day or two, but here's what he sent me.

(https://i.imgur.com/4WOBYTl.jpg)

(https://i.imgur.com/t7yXnL5.jpg)

(https://i.imgur.com/BKC5iX7.jpg)

They are 2mm larger than our VM's that we ran last year on our Water Buffalo, and they came off a GT750 from one of the cars my father raced against. Period for the vintage of car, and likely a sweet upgrade. He's going to send them to us. We will have to work out throttle cables, but I think we are going to give them a try.

Check Packard Racing for throttle cables.

Our cables are pretty specialized considering they run from a throttle pedal at the front a car back to a mid engine motor in a chassis that was built by my father 50 years ago. I appreciate the response though.

Lectrons need cables with lectron threaded ends to go into the carb tops, so you need at least the piece from the carb to the splitter.
Probably worth a call.

Inside the plastic organizer that had the book on top are a bunch of parts for connecting them up. The slides appear to use a standard barrel type termination, but I could be very wrong.

So there is a good bit of hope for some racing this year. Covid cases are in freefall and vaccinations are climbing rapidly, that includes my father, he's 72.

This in mind, my father is feeling much more optimistic for 2021. We spent a few hours working on the car yesterday, mostly playing with driver ergonomics. They weren't quite right and it meant that a variety of issues existed with my fitment in the seat. Mostly my head angle incorrectly accommodated my HANS device. That said, we also worked on the motor, it's almost back together but I managed to grab these photos.

(https://i.imgur.com/4Umhuif.jpeg)

(https://i.imgur.com/sCiM5Ay.jpeg)

(https://i.imgur.com/UvFxFss.jpeg)

That aluminum timing gear looks dead sexy Chris.  Back in the day Wassell in the UK used to sell aluminum three keyway timing gears for Triumph twins.  They did wear faster than stock steel gears but not by much and they don't crack like plastic Suzuki gears used to.

I looked into doing them out of 7075 as well as brass and even steel.

I might just anodize the next round of them. Since I don't spend a lot of time minimizing tooling marks around the center of the gear it probably won't look amazing, but the teeth come out great and it would add a lot of resilience to the wear surfaces.

As you well know, the stock gears are pretty marginal. When busting the gears off the hub they come apart so easy that it's amazing they ever worked. There clearly isn't much load on them.

I forgot to post this. Our BDK magnesium water pump cover apparently wasn't cast too well. It has pinholes all over, but also one giant hole that seemingly formed. I am going to do some backwards engineering and just machine one out of 6061. It won't be as elegant as the cast version, but it will work, and it probably won't develop holes in a year. I might do an impeller while I'm at it.

(https://i.imgur.com/IsMnmIP.jpg)

I did a test run with some machinable wax. Figured I could fit it up before actually making one out of aluminum. This took quite a bit of reverse engineering and I can tell right off the bat there's a few things that need some work on the model side, but it seems like it's a good start.

(https://i.imgur.com/78VXlRc.jpg)


(https://i.imgur.com/ELh2mz7.jpeg)

That's a nice piece, but can't you just use a stock GT750 cover?  I have a brand spanking new (NOS) one here looking for a new home.  Yours in exchange for a small pile of drink vouchers.

The housing is actually deeper as to accommodate the taller impeller.

Replicating (well not the back side for now) this but hopefully without the porosity - https://bdkraceeng.co.uk/tc/products.php?281&cPath=6_68_79

Semi long day of taking care of my wife who has pneumonia and machining stuff when I could.

(https://i.imgur.com/aacbbgf.jpeg)

(https://i.imgur.com/ePUbWD3.jpeg)

The wax one fit perfectly. We sectioned it on the band saw so we could see the fit to the impeller. It appeared to be spot on. So I went for it in aluminum. We test fit tomorrow. Plenty of time for a version 2, but I really hope it doesn't come o that.

We are on track for our first test this year in 6 days.

Things are looking good! Coolant is in check. No major leaks (lol), a bit of a drip at the transmission, it will be fine. Brakes are bled, totally new brake setup for us (modern stuff thankfully), I think it will stop. The clutch seems marginal still. Not a big deal for a race car assuming I don't spin or otherwise stop. Seating position is tough, but I will deal.

Everything is set for a Friday test at Pitt Race. I can't wait to run Pitt Race in anger again, I literally lived at the track for a summer in 2010 when I worked in exchanged for free track time as I launched my short lived professional driving career. I have raced at least one race a year until 2020, it broke my 25 year streak. At my best, I raced 35 some races a year, so 2020 was quite painful. I can't wait to turn some laps in anger. I'm sure my Sportwagen will enjoy the relief.

I also get my first vaccination tomorrow (please avoid political commentary), I feel extremely pleased with this. I am feeling very optimistic for 2021.

We're out here cheering for ya Chris  :cheerleader:

Thank you!

We just push for fun. My father loves the challenge (me too), and the hard work keeps me out of trouble. There is nothing to be won or gained asides from personal satisfaction.

The Pittsburgh Vintage Grand Prix track is rather unique. Something akin to a proper road racing circuit that have mostly gone away. It's very dangerous, but insanely satisfying to race. I hope we can realize our goal of resetting the all time lap record. I kind of doubt it will happen this year. Next year seems very possible. Development cycles are very tough. We are reasonably versed, but only have so much time and money. Such is life.

We had a fairly successful outing yesterday. Despite on and off drizzle there were enough cars to keep the track dry for our three sessions. We probably ran around 20 laps total despite having to go through basic checks with several stops through the pits.

Cooling seems to be working very well. That huge impeller kept water temps against the thermostat during all runs. I think we are good there. Ambient temps were in the low 50's, but if we had a major cooling issue it would have shown up despite that. The new water pump cover did exactly what it should do, which is hold the water in and get it from point A to B. The major clutch slippage issues we had are completely gone. The brakes work and work well, which is confidence inspiring. This all added up to a huge jump in performance from our last outing. We also went significantly longer in final drive ratio from our last time out, that made a huge difference in drivability. The engine seems to have relished in it too.

Jetting seemed very good and the engine changes we made over the winter kept the RPM range in a much safer range. It was still pulling hard at 8500 and definitely would keep going but grabbing the next gear put it back in the meat of the power. We ran a mix of the oil pump and 40:1 premix, it produced a nice blue smoke once cleaned out and fully warmed up. The car really hauls and despite us not really evening coming close to the full potential of the car we were able to outpace a lot of serious hardware. We managed 120mph on both the front and back straight and it has a lot more in it. We were geared a bit short for Pitt Race, and I wasn't particularly taking the car deep into the brake zones, nor was I working it particularly hard or well in the corners leading onto the straights. Given better mid corner speeds and later braking it stands to reason that we could probably get another 5 to 10 mph out of the car, and that's a conservative estimate. Plenty of speed left.

The bad news, the charging system wasn't working. We ran out of voltage and gained a high RPM misfire in the second session and eventually it pooped out before I made it back to the pits. It should be an easy fix, except we couldn't identify any issue with the alternator or wiring. The seat and seating position is perhaps one of the worst I have ever encountered. In right hand turns I was falling out of the seat, literally. The track is clockwise, so it was like most of the turns that I was hanging on for dear life and thanking my 6 point harness for not letting me go. A big redesign of the seat is going to have to happen before the next test. Then our data acquisition simply would not work. We couldn't even connect to the logger to diagnose it. Finally, the clutch (as in disengagement) only worked like twice then gave up. Not a big deal at a track with a huge pits where you can get it rolling and then pop it into gear, but it will be a significant issue when we get to the Pittsburgh Vintage Grand Prix were pit space is minimal. Of course the clutch is never used outside of the pits, so the other issues will get focused on first.

All in all, the car is ridiculously fast and I am way too out of shape to drive something this fast. The bad seat certainly didn't help, but I will spend the next few months going to the gym and eating like a bird.

We are hoping for another test in about a month. Plenty of time to get the issues sorted, we hope. The Pittsburgh Vintage Grand Prix is the third weekend in July. So we are feeling a bit ahead of the game, but anything could happen between now and then.

Here's the only picture I took. We built the trailer too.

(https://i.imgur.com/47HdvaV.jpg)

 :clap: Love these updates. Thanks for letting us live vicariously.

Hopefully I'll have some in car video after the next test. That way you guys can hear the sweet song she sings.

I spoke with Dave (my father) today. We are doing a seat fitting tomorrow with the hope to make a test Thursday. I hope we will schedule at least one more test before we race in July. Of course we have to be a bit cautious to avoid using the thing up. It's a born sprint racer and the design has little consideration for longevity as far as rebuild cycles are concerned.

In there, we might have time to build out a few prototype parts as well. Most likely suspension parts as the unsprung weight for the car is pretty terrible.

We decided to postpone. I have to run to Eastern PA for work Monday Tuesday, and forgot I am coaching drivers at Mid Ohio from Friday to Sunday. As to hopefully preserve my marriage I decided two more days away out of the next 7 was probably best avoided.

We are heading to the track on the 11th.

The clutch seems to be fixed, it was a geometry issue on the slave cylinder. We are doing a seat fitting on Saturday. Nelson Ledges here we come. Probably the best road course nobody has ever heard of.

The car is together. The seat has been vastly adjusted, I think it will work this time.

We have some updated aero, the front of the car was feeling a spot wandery at top speed while it was perfectly stable up until about 105/110. So we added a front spoiler and two new fender vents on the front. Hopefully helps seal the car to the track a bit better and relieve any high pressure buildup on the underbody. I'm not digging the all black spoiler, it detracts from the look of the gar big time, but it is what it is.

Automobile aero even at high levels was more or less purely an art form when my father built this car, and the car has already gone faster than it ever did in the 70's. As a result I expect us to have to do more tweaks like these along the way.

Nelson Ledges is quite a fast track, in fact it is said to be the fastest road course in North America. I am not sure if that is true, but I do know that it is incredibly quick. We will certainly be geared too short, but we aren't really testing for Nelson Ledge's, we are testing for a street course. So it's important we stick to slightly high ride heights, a little too softly sprung, and a few other small adjustments that make manhole covers, cambered roads, and curbs easier to navigate.

(https://i.imgur.com/TVrK4QC.jpeg)

(https://i.imgur.com/GguYCdN.jpeg)

Well, we got out yesterday. Weather was damned cold and windy, not even getting into the 50's.

Overall it was a good test. Easily the hardest we have pushed the car. We were jetted a bit lean and never quite caught up with it, it didn't want to rev much past 8,200 which we achieved after bumping the mains up.

The good, we are feeling confident with the cooling. The car sat on the thermostat all day. The seat works now, I managed to run 10 laps without feeling like I was going to die. In fact, I was almost comfortable. A bit more tweaking and the seat will be perfect. Nothing broke, and the car ran pretty much without issue, though it did load up on the grid once. Our tires are old as dirt, that may seem like a negative, but given the performance we achieved on old tires we stand to make serious gains on better ones. We have to run a grooved vintage approved tire on the car, not a proper slick, but new ones make a huge difference. I calculated about 6mpg, which puts us right in the window to finish a standard race with our 5 gallon tank. We got actual data, RPM, voltage, EGT temps, wheel speed, lap time, but no accelerometer so no track map

The bad, we still aren't braking quite as well as we should. The brakes work well, but it just isn't stopping as fast as it should. I might not be achieving enough brake pressure, that's a me issue, but at the same time I never felt like adding pressure would make it stop faster. I don't know? Battery management is still a bit precarious, the car is charging now, but system draw is high enough that if we don't keep the car on the jumper things get a bit touch and go when navigating the paddock and grid. The car only charges over like 35mph as the alternator is axle driven. The car is a bit twitchy loose near apex and on power loose after apex. It wasn't exactly confidence inspiring on a track where we averaged 95mph and topped out at 125mph. I wasn't super pleased with our ultimate pace, we should be a good 5 seconds a lap faster. If spares existed for the car I probably would have pushed a bit harder, but there are none, so I had to run up to a comfortable limit and just stay there. I didn't get any video, I forgot the Micro SD card at Mid Ohio last weekend. Jetting, we aren't there for 90 degrees in July as we've done zero warm weather testing.

We may push for one more test, or we may just adjust some things and hope for the best at the PVGP. I don't know yet. The PVGP is late July, so plenty of time to plan and scheme.

Double posted accidentally.

I'm going to make a really long story as short as I can.

Front brakes, the balance bar wasn't right, we've fixed that. New rotors and pads too.

The Koni dampers were all junk, they are still junk, just better. This may be good or bad, we don't know yet. Obvious issues have been repaired, but we don't know how that will change the car. We've gone to a droop limited setup, fundamentally better than the old arrangement. Wish me luck.

My father made a new steering wheel, it's awesome (I really wish I had taken a photo, it's classic Dave, super functional and beautiful in that sense), we just need the steering to be a bit less sensitive. The new wheel is larger in OD by a lot, well as much as it can be and still get my legs under it. An 800lbs car is not hard to steer.

We are on track this Saturday. I have two video cameras ready and will take photos too. I assume the thing will melt down before I get actual proof of it turning laps.

Oh, and I've lost 13lbs and am trying to be less of a garage rat. When I drove professionally, I was fit as all get out. Life has changed a lot in the last decade... I'm only like 15lbs over where I'd like to be now. So hopefully by race time I will get there. 7 weeks to go.

This is a great read, Chris. Thank you for the updates!

Thanks, man! We are pushing pretty hard on this, which is a kind of silly, but I guess we are having fun.

We went back to baseline on the jetting with exception of the mains. We monkeyed around a bunch with the carbs and all of it was bad tuning except that mains. I ordered a new data acquisition system, we will get lap times and real data this time. Though my father is confident he has fixed our Pi system (fourth time is a charm I suppose). We may get double data, which is perfectly okay. The new steering wheel also moves the Pi mini dash up to the top of the steering wheel where I can see it. The seating position is so reclined I cannot view the center of the steering wheel where the mini dash was mounted before.

Assuming we aren't totally lost handling wise after the damper rebuild, we will go faster this time. The brakes alone are worth a good four or five seconds assuming they work as we need them to. We will also dig into tire temps and actually start to work on handling. Testing has almost all been reliability and function based until now. That said, this will be our last test before the Pittsburgh Vintage Grand Prix. So any developments after this test will go straight to the race without confirmation. Classic racing scenario.

Finally some video.

https://www.youtube.com/watch?v=jyTmjOpD-Cw

We didn't melt down, we didn't break, in fact we ran the most laps with the best reliability in the hardest conditions we have faced thus far. That said, we were left a bit perplexed on a number of issues. There's a lot to unpack here, and honestly I am not sure where to start.

Hopefully video is good for something. Once we have more answers I will talk more on the technical aspects of our test.

I've raced Nelson Ledges,  Have fun and yes, the cheapest way to go faster is losing weight.
  Cheers, 50gary

In our case the cheapest way to go faster is to fix the brakes and get the handling sorted. I'm sure we can go many seconds a lap faster doing those two things.

Of course it's easier said than done. We are picking through data and performing set down and simply don't have any decent answers at the moment.

So we are like 12 days out from the race. At this point the car is basically as ready as we are going to get.

From the last test we came up a with a few issues;

• The carb tops on cylinders 1 and 3 kept coming lose causing various issues
• The jam nut on the throttle cable loosened cause the throttle to hang high
• There's a significant late corner oversteer
• Brake performance remains too low, locking the front brakes doesn't seem possible
• We definitely weren't jetted all that great for the 90 degree heat

So we've safety wired all the carb tops and fixed the throttle cable issue. The late corner oversteer is a bit of mystery, the car also wanders a bit on straights. This could be a combination of things, there is nothing glaringly wrong with the car. We revisited bump steer on all four corners, it certainly wasn't bad. We made it better. The alignment wasn't bad, but we've adjusted it some. The wandering on the straights could be a lack of caster, we've left this alone for now. The late corner oversteer is quite puzzling, the rear of the car just gives up when the load on the rear tire should be decreasing. It's a very unusual and particularly unsettling feeling. The thoughts are that we have some mismatch in the anti-squat and that we are unloading the inside tire late in the corner as the car returns to full throttle. For now we are going to throw a little more anti-roll at the front of the car and a little less anti-roll at the rear of the car. We fabricated a stiffer front ARB and installed it. We will do some bar scans at the race, this is not something we have played with yet as other issues have been more important. The car has never exhibited any understeer, not in any phase of the corner. So less compliance at the front might help. Of course loss of grip in order to change balance generally is not the right strategy, you might gain balance but that doesn't necessarily mean faster lap times. That said, more roll stiffness at the front tends to keep the rear of the car more planted, so maybe it will work? The brakes remain a bit of mystery, we've installed a softer compound pad that will function better at lower temperature. If the pads don't help, then we will have to install a smaller master cylinder or larger piston calipers, neither of which we have. Of course the car uses an odd pull type master that mounts on a spherical bearing, it's a great design that's also a bit expensive. The calipers and uprights are off a Triumph, so not exactly super common stuff anymore. Basically, new front brakes will be a project for 2022, and will probably mean new uprights and new calipers.

Anyways, the car is about as prepped as we can make it for this years event. We will load up this coming weekend, the paddock opens the 23rd, we qualify on the 24th, and race the 25th. I will be getting more pictures and video and will make sure to post here.

Good luck! Hope it doesn't drive like a Fiero - you had to bounce back and forth between gas and brake through a turn.

Thanks! I always liked the rounded Fiero. Kind of a neat ride.

When we get this thing right I will be to 100% throttle a few feet before apex all the way to the next brake zone. We weren't there at the last test, not even close really.  Hopefully we gained on it some for the race.

I need to get my RD going again, it makes for a fun pit bike and generally I leave it over at the bike show for half a day. I bought an HPI ignition last fall and never performed the install.

And remember, there must be pictures and video!

Yeah, I am going to try to get some more detail shots of the car. It's a pretty simple setup, but I have been so lax in photos lately that I need to step up my game. I am also going to make some new camera mounts to get a little better video. I have two cameras currently but I am considering a third. It's just a matter of spending the money.

Camera is ordered. I bought an off brand "4K" camera for $25 on eBay. Lol. If I get 1080 out of it I will be satisfied.

I am going to mount it right on the front splitter and attempt some high speed footage of the asphalt racing by. Who knows if the camera is worth a shit, but if it falls off and gets run over I won't be sweating it.

I need to come up with a video lackey. It's hard to wrench, drive, analyze data, dad, socialize, and work the video all at the same time. It's just a lot of moving parts.

I can't wait to hear this car scream

There's some video a page back or so. The car is too quiet in my opinion. I am going to talk to my dad about it.

We qualified sixth in our field of like 25 cars. The left cylinder carb slide hung and I only completed two flying laps in qualifying. Quite interesting to drive a car that is stuck semi-full-throttle. I lost brakes at the end of that second lap, not totally, but definitely enough to just totally get out of it.

We broke a half shaft in the practice session, then the carb slide issue in qualy. Not perfect, but we soldier on. We have literally zero spares, but luckily we found a guy with a welder here at the track and my father zapped the half shaft up. It's a little gross, we will see if it holds.

Most of the issues from my last post have been pretty well addressed, we just keep running into little issues here and there. Part of that is a result of the increased pace, but also the massive stress a street course like this produces. The car is so quick, I am barely scratching the surface. We won't likely get to where we want with only one more session and the race tomorrow. Even with the continued issues, we will progress.

Here's some pics. I have video, I have more pics, but I am tired. I will get some video together in the coming days. I included one photo of my son walking on the bridge railing that we normally would never have access too. I am just glad he is appreciating motorsport.

(https://i.imgur.com/Ju9Lrmg.jpeg)

(https://i.imgur.com/i0PNvg0.jpeg)

(https://i.imgur.com/41dwUfn.jpeg)

(https://i.imgur.com/sjyPg2y.jpeg)

(https://i.imgur.com/24opyCV.jpeg)

(https://i.imgur.com/WnlmvlM.jpeg)

Good luck tomorrow!

Start looking now for a half shaft and DOJs/CVJs to handle at least twice the power. We tried indy car joints on a 400 Pontiac in a dirt track car - wrung them off constantly. Ended up with slip joints and 8 ton truck U-joints. Not ideal, but best available in the late 60s. Nowadays, plenty of higher performance independent suspension production cars provide higher strength joints. Breaking a half-shaft mid acceleration out of a turn could result in agricultural racing.

Still, you'll have a ball today if the brakes and throttle get sorted.

Thanks guys!

The brakes overheated on account of the throttle being stuck, so they should be okay. The drive shafts use typical VW CV's, I am confident they are probably still used on models today, but they are shortened shafts. The weld holding the splined section into the half shaft tube broke fairly cleanly leaving us to believe the machinist who did the work just didn't get good enough penetration. We couldn't exactly pound the heat in with the little flux core welder either, but we put a nice fillet on the mating surfaces and were able to apply a nice big weld. It's not all that pretty, but I think it will hold.

Well day 2 went a bit better, but not good enough. In the first session the same drive shaft broke, again, but this time in a different spot. So we took it off and got it welded. This time we made the short trip to our friends race shop and used the big Miller MIG machine. Keep in mind the flux core weld from the previous day did not break. The only conclusion is that we are stressing stuff more than we have ever stressed it before on the rough and tumble street circuit. Fair enough.

With the repaired drive shaft we went into the race less than optimistic, but oh well. Off the start I got a nice jump getting two cars immediately. The car in front got bogged down by a poor start from the 4th place car and I managed to overtake him on the front straight moving me to third. The car was working nicely, temps were good, and the tires were starting to come in. I started pushing pretty hard, the hardest I had pushed the entire weekend. Sure enough I ran the fastest lap I had run this weekend, lopping several seconds off my best time. I caught a Formula Ford ahead and quickly passed him putting me into second place.

At this point, first place who is many time winner of the event, was long gone. The leader has in the past come within just a second or two of the all time lap record, and I knew I wasn't really a match for him on this day. So I put down another personal best lap and gapped the Formula Ford by quite a bit, then decided to settle into the race a bit and just preserve the car. By lap five I started getting a good bit of brake fade, and with the gap both in front and and behind large I slowed my pace to allow the brakes to cool. The Formula Ford in third caught me and I actually just let him past, I knew I had him on pace but I also knew I had to make it to the end. So I hung on his tail just managing my brake fade and sure enough the pedal was coming back to me. The plan was to hang onto him, then with two laps left I would get by him and retake second, with the pace advantage it would have been easy. However, water temps were starting to creep up, it was now right around 250. Too high, but not exactly catastrophic.

Unfortunately, three cars in separate incidents caused a stoppage of the race. Race control instructed us to park while course cleanup removed the cars from the racing surface. During this time, the heat soaked engine, while not even running mind you, continued to overheat and blew the head gasket. The car only pumps water while running, and without any fans the radiators were unable to exchange air anyways. A big lesson to learn there. We had to park the car, and as a result received a DNF. We officially ran the third fastest lap of the race.

Our best time was a 2:19. The fastest lap of the race was a 2:15. The all time lap record there is a 2:09.4. Performance wise we are still barely scratching the surface with the car. Even during my best lap I was basically taking it easy, and we still have a number of technical issues to look at.

In the tightest left hand corner the car was fuel starved, I believe, and it would just shut off. I was losing 2 to 3 seconds in that single corner alone as I waited for the engine to re-fire and take off. The live axles generates so much force on the multi-link rear suspension that we are eating up heim joints like they are Cocoa Pebbles. This results in a rather sloppy rear alignment and causes all sorts of fun things. We may revise the rear spool and adapt a differential. The Ikon dampers are okay, but we can do much better. We made huge strides on the brakes, but the brake fade is unacceptable. Keep in mind the track has 21 turns and most of them require braking, so brake stress is very high.  Perhaps some brake inlets will solve that issue? Tires, well, we have been running the same set of tires since we first ran the car in 2019. They have many, many sessions on them. On a two minutes lap, tires make a huge difference. In summary, there is plenty of time left in the car. We might be behind our development curve, but we are much closer now.

Overall, we are disappointed we didn't bring home that second place finish, and the DNF stings a bit more. Had the race not been stopped we would have made it to the end. Even if I had to nurse it to third it would have been a nice cap on the weekend. However, we know the potential is there. We have so much pace left that the all time lap record is within reach. 2022 here we come!

Here are some pictures. I have tons of video too, I will get it trimmed up a bit and try to post it.

(https://i.imgur.com/fRo41nW.jpeg)
(https://i.imgur.com/r6xJ8yw.jpeg)
(https://i.imgur.com/c440ivx.jpeg)
(https://i.imgur.com/hX1Xb4f.jpeg)
(https://i.imgur.com/bc1IOIg.jpeg)
(https://i.imgur.com/ZJSkgqt.jpeg)
(https://i.imgur.com/4CE5CUO.jpeg)

Some short video. In the second video you can see it smoking pretty nicely, a blueish-white smoke.

https://i.imgur.com/GfmfOrg.mp4
https://i.imgur.com/IdhrQgL.mp4

False edit.

Racing and learning. I would suggest (maybe after you decide on differential) having a couple axles turned from appropriate metal and splined as needed. We even did that on the dirt track cars in the 60's (usually from old wide track Pontiac axles).

I think we will probably move to a tripod type arrangement, moving away from CV's. A little more axial movement is good for us, it just allows us so much more flexibility with setup of the rear suspension geometry since tripods provide more plunge. Also, tripods are soooo much easier to deal with compared to packing VW CVs. They just aren't that much fun even when you are good at it. We will probably buy the tripods but machine the half shafts and couplers in house. Since we aren't too concerned about driveshafts hanging out in the air stream on account of the full bodywork, we can use a fairly large OD tube for the shaft, this should afford for a very light setup, while also providing a much larger surface area for welding the splined sections to the tube. The two welds where the splined section was sleeved to the half shaft tube is what failed (twice) on our left side half shaft this weekend. Large OD drive shafts I guess are typical for just about every drive shaft known to man these days assuming aero isn't a concern.

We definitely have not decided on a differential, but we have long discussed a Quaife limited slip setup. They aren't uncommon in chain drive cars, and can be found used for reasonable prices. Building a new spool for the rear of the car is a big project, and also expensive. We may not even approach it. It would probably make us faster, but it introduces a number of other challenges to face.

Anyways, we have lots to soak up. Honestly, we have spent so much time on this project we will probably just forget about it for a month or two. Hopefully we will gain a little bit of perspective and clarity along the way. Then we will get back into the design/engineering phases. We are tossing around the idea of hitting the Put In Bay vtinage races, but we aren't sure yet. That said, my father plans to pull the head off today and have a look. There is no doubt we blew the head gasket, it's just a matter of how bad it is.

My wife just got home with my video. So I will start working on it.

I think this was my fastest lap. I watch entirely too much in car video since I driver coach, but I was totally phoning it in. So much pace left. This video is low quality, I will get a 1080 video uploaded as well.

https://www.youtube.com/watch?v=bC5vVgyr4rg

This is fantastic, thanks for sharing. It's great that you and the family are having so much quality time, and that this machine is back where it belongs! It looks like you weren't even really trying on that lap, so smooth and drama free. Good luck with the next steps!

I was definitely taking it easy under braking and in the long sweepers where maintenance throttle was needed. The loose heim joints on the rear toe links offered up a challenging bit of rear steer and fast inputs caused instability. There isn't much room for error on that circuit and since we only have one of these cars and zero spares it seemed best to just be calm and let the car do the work.

That said, there's nothing wrong with being smooth. I tell drivers all the time that they need to do less work, as over driving generally just slows you down.

Two laps and better quality video.

Nice video.  Thanks for sharing.  Racing old cars and bikes  is a fun pastime and as they get faster and older, things start to break.  Make that part stronger and something else starts to give up under the strain. 

I like the fact that the car still looks like it did and hasn't morphed into a carbon fiber, modern interpretation.

Engine sounds good.  What's the chirping under brakes?  Is that brakes or tires or something else?

Random direction changes are never fun, especially with the "runoff areas" full of trees, rock walls and drop-offs.

The only think that could make the videos better is to put the mic closer to the exhaust  :olaf:

Quote from: teazer on July 28, 2021, 10:27:28 AM
Nice video.  Thanks for sharing.  Racing old cars and bikes  is a fun pastime and as they get faster and older, things start to break.  Make that part stronger and something else starts to give up under the strain. 

I like the fact that the car still looks like it did and hasn't morphed into a carbon fiber, modern interpretation.

Engine sounds good.  What's the chirping under brakes?  Is that brakes or tires or something else?

I think that chirping is the chain drive, likely the chain is a bit too loose and rubbing on the inside of the chain guard. Either that or it's the transmission. Who knows?

We have been very careful to keep the car true to its origins. Outside of safety measures and modifications required to make the car function, we have modified very little. You are absolutely correct that many convert to carbon bodywork and sorts of other items that never would have been possible in period.

That said, most of these cars end up faster than they ever were simply on account of tire technology being so much better. That of course means some things have to be modified to just to stand up to the extra stress, as you mentioned. Keep in mind we went many seconds faster around Nelson's than my father ever managed and he was on slicks while we are on grooved tires.

Tires - SO much better for cars and bikes alike. Also brakes and shocks. You should get the braking problem sorted this winter, and the chassis looseness may require heavier components or different materials (or both). I'm sure the half-shaft problems will improve with better materials and welding technique. 

The machinist that did the half shafts has been dead for 10 years, and he did the work 47 years ago, so we can't even ask questions. Obviously it wasn't well thought out. We will certainly do new half shafts. Luckily we can just do them in house now, which wasn't the case 47 years ago. lol

Brakes, yes. Heavier heims on the rear toe links, yes. We should also jig up front and rear links and record numbers so that if we have to refit a link we can dial it in without hitting the setup pad.

p.s. teazer I owe you a water pump gear, I haven't forgotten, I am assembling 8 more gears next week and one has your name on it.

Really glad to join this site to be able to see this.  Great car, even with the engineering complications.  Always thought to build something off a GL1000 base, but more because of the boxer arrangement and it being a shafty seems so much easier to build retrofits, even if it's not. 

Quote from: sav0r on July 29, 2021, 02:09:14 PM
....
p.s. teazer I owe you a water pump gear, I haven't forgotten, I am assembling 8 more gears next week and one has your name on it.

No worries Chris.  I know where you live.... :whistle: :eek: :cool:

We were gearing up for either Put in Bay or another test but I think we are going to hold off now.

The half shaft design is incoming, but more importantly, my father is prepping to move the Express chassis under the Grumman step van body. This will leave us without a tow vehicle for the time being.

We are also studying another head and cylinder, maybe a reed valve cylinder. Maybe a totally bespoke head. Lot's of work to do, as usual.

Big advantage of reeds is the added transfer port area which that motor needs. 

Disadvantage is the studs tend to get in the way and they are challenging to fit.  Check out the barrels that Brett DeStoop cast for a 1000cc motor or his 750 reed motor that made something like 176HP IIRC.

I wanted to graft a set of snowmobile top ends onto a GT750 set of cases but that requires moving the left cylinder out a bit and changing the crank and at that stage, might as well saw the transmission off and weld on a GSXR trans with stepped gears for a shorter motor....

A Zeeltronic or ignitech programmable ignition would probably help to spread the powerband too.

There was a guy in Germany that built a 1000cc motor and added powervalves to the exhaust as well as reeds.  That was a huge amount of welding and machining.  You could probably machine a cylinder from billet with modern machine tools and an unlimited budget.

According to the rules we can go to 850cc. Right now we are like one overbore over, I forget what that comes out to, but I believe we are under 800cc. Anyways, we started the topic of building a second top end as a result of the displacement we have left on the table. Our current one works very well, and the cylinders are plated. So we want to keep it as is. So if we were to do it, the idea is to bore to get closer to 850cc, port, maybe do reeds, and consider a head design. Once the machine work was done on the cylinders we'd probably get them plated again. We are happy with our current head work, performance across the cylinders has been great, but the head gasket situation remains precarious. As you well know. The head design would mostly be to solve the head gasket issue, not particularly there to help with performance, though I suppose that goes hand in hand.

A larger impeller has been designed. This is another 15% larger than the BDK high capacity impeller. We figure we have almost nothing to lose with this. If it doesn't work we just revert to the BDK impeller and our custom housing. I will machine this impeller and a new even larger housing this fall. The new/revised housing will get some nice touches along the way.

After we picked through some data it appears we were generating the most heat at low speeds. Likely a combination of low airflow through the rads and low RPM generating less water flow through the cooling system. Hopefully a bit more flow from the pump will work out for us. Street courses are a bitch.

(https://i.imgur.com/Bq9frtM.png)

Nice. I'm sure you have already checked proper sizing of hoses and connections as well as potential kinks developing when the hoses heat and soften. Also actual testing of both the thermostat and radiator cap (I've experienced bad new ones).

The plumbing on this thing is incredibly straight forward and seems to be in good shape. We run a 6psi cap and it seems to function, and we built a new accumulator tank that appears to be working fine. We do have questions about the internal conditions of copper/brass radiators. They probably could use a good flush if not torn down and cleaned. It uses two radiators that are approximately 8" by 10". So approximately twice the radiator of a stock GT750. 'They' say, "twice the power, twice the heat", or something like that. We were okay at race pace on a proper racing circuit where average speed remained high. The street circuit however has a lot lower average speed. We are also adding some inline coolers, the finned type ones. We aren't sure they will do much good, but they look cool and offer little weight penalty so we figured it was worth a shot.

That pressure should be good for 230 F if straight water (which I believe most tracks demand). Heat exchange to air is always a weakness, but I'm sure you already have a lot of air huffing through the radiators. Street races also require a lot of acceleration from slow corners, which would be heat builders. Heat up accelerating, then slow down for the corner just when the heat wants out of the block. My '77 GL1000 fans never came on except after a long 55 mph run followed by slow traffic. That heat builds up in the metal and still wants out. If weight and electric power is still in consideration, maybe bigger electric fans for the tight courses. I think you are working up a great little racer there that will alliw you to concentrate on building your skills as driver.

The street track is certainly where a lot of our challenges are coming from. It's rough, it's long, it's usually hot as hell, and you slog the engine through sections at 110mph and sections at 25mph. It's quite the ask.

We don't have any fans, electric or otherwise (maybe a handful of human fans). It's a road racing car, and fans generally aren't common. We'd much rather cool the thing without the extra weight, parasitic drag from the alternator, and potentially increased weight from the larger battery requirement. On a street course it may ultimately be required though. I think we will try the larger pump first. We will probably find that the thing won't get off the thermostat when we get to proper tracks.

I've been racing for 27 years and have in the last five or so years started to unbuild my driving skills. Once upon a time I drove quite well, maybe even won some races and set some lap records. These days I am focused on other things, I suppose.

Heat management is quite a challenge because you need more (as in additional) cooling at low speed.  High air speed helps when going fast, but at lower speeds there's less air flow and more heat to dump.

I would try an electric water pump tied in to a thermoswitch. The stock fan switch should work or get a lighter switch.  Current draw might be high so that would potentially need a larger battery or maybe a separate battery for the pump with a relay. 

The problem with a larger impeller is that it pumps even harder (bigger power loss) at high revs and you have sufficient cooling capacity at top speed already.

What about air flow across the radiators?  Is there a way to improve low speed air flow without adding drag at higher speeds? Time to build a wind tunnel.......

Quote from: sav0r on August 11, 2021, 08:18:14 PM
According to the rules we can go to 850cc. Right now we are like one overbore over, I forget what that comes out to, but I believe we are under 800cc. Anyways, we started the topic of building a second top end as a result of the displacement we have left on the table. Our current one works very well, and the cylinders are plated. So we want to keep it as is. So if we were to do it, the idea is to bore to get closer to 850cc, port, maybe do reeds, and consider a head design. Once the machine work was done on the cylinders we'd probably get them plated again. We are happy with our current head work, performance across the cylinders has been great, but the head gasket situation remains precarious. As you well know. The head design would mostly be to solve the head gasket issue, not particularly there to help with performance, though I suppose that goes hand in hand.

I didn't realize the bores were plated.  That sounds like a good idea. Stock liners are a little thin and not centrally placed, so going larger may require new liners and if so, might as well go with aluminum (plated) liners.

Head gasket leaks are an issue with those motors and I believe one cause is the uneven stud spacing.  And using inserts tends to exascerbate that. Brett DeS bolted his inserts to the top of the block with a ring of smaller bolts on his big bore motors to stop the leaks.

The alternator is axle driven, so it only charges over like 45mph. It doesn't appear to be in an issue as the data shows the voltage remains steady throughout the course, but it could be an issue if we run fans or an electric water pump. I proposed using some RC batteries and a fan to my father and he wasn't super into it lol. I figured I could just turn them on in the tight sections, turn them off in the fast sections. It would probably help. At this point I think we will take the hit with the larger water pump, it probably won't cost us much, but it should serve to move more water even in the lower RPM ranges.


On last tear down it seemed that since the tube nuts are in a bind on account of the rather inconsistent studs, that we aren't likely getting accurate torque numbers when torquing the head. So we made some new tube nuts that don't fit quite as tight, we might have to pin the head as a result.

My father turned over a cylinder and a few heads. I haven't gotten started yet, but I plan to work/explore a new head design as well as potentially converting a cylinder to reeds.

Yep, our good cylinder is plated. We were just hoping for better longevity out of the cylinder since it's fairly one-off.

The LiPo idea might work well with am RC motor, controller, and ducted fan like they use on electric jet models. They have by design very strict weight limits.

We have an additional aluminum radiator we might add as well. I dont think any active cooling is in our future. lol

The Dave man does as the Dave man sees fit.

My 125 shifter kart had its radiator in the back behind the driver. Slightly offset for weight balance. It would overheat under yellow flag laps and generally ran a little hot. I opened a hole in the nose and mounted a tankless aluminum heater core and ran hoses front to back. It stayed at 130 degrees always after that. No fans. I think a lot had to do with the extra coolant capacity from 12 feet of 5/8" hose. I wasn't that weight-conscious. It was 15 lbs over the minimum for the class which was with driver. I could have lost 15 lbs...

IR8D8R

to jump in late in the game here... regarding cooling, try to use aluminum coolant lines wherever possible, will shed heat along a pipe where normal rubber lines insulate heat in. every little bit helps. even adding fins to the lines along the length helps.  .02

Asides from some connections it's all aluminum lines. The lines are actually made out of a collection of aluminum tubes sourced from folding chairs lol. Nice thin wall and the preformed bends made for short work of the plumbing.

We are going to flush the radiators. There is a good chance they aren't flowing properly. We fought with this on my friends Elva, no matter what we did with that car (MGA motor) it would overheat. Finally we got fed up and did a radiator flush and that solved the issue.

Snapped a photo of the inline coolers. Just to reiterate, the car cools fine when average speeds are high, but on the street course the tight sections tend to build a lot of heat.

(https://i.imgur.com/iiB1nBe.jpeg)

I printed the new impeller and cover and some where along the line I messed up the dimensions on the cover. We tried a test fit, and I could already tell it wasn't going to fit, and sure enough it didn't fit. Back to the CAD software. Better test fit with plastic than make chips though. The last time around I machined the wax test part, the 3d printer is easier, albeit way slower.

(https://i.imgur.com/9eUFELP.jpeg)

I got the dimensions on this all ironed out. We test fitted a new print of the impeller and cover. All is good.

I went ahead and did some final design on the cover. I just wanted to make it less of a slab and pretty it up some. I'm not sure I achieved that, but it at a minimum is no longer just a brick. I also designed the soft jaws to hold this bad boy. I await the stock to start machining.

(https://i.imgur.com/OSmyFbn.png)

Impeller done. I was waiting on some new soft jaws that I will machine to reflect the cover. They will hold the cover as I machine it in the B side operation, they arrived Friday. I go to put them in the tool box where I keep all my machining stuff. Well, I already had two sets of soft jaws of the same dimensions. I just assumed I used my soft jaws up, I was mistaken. I could have made the cover three weeks ago. 

:help:

Anyways, the cover is inbound. Everything is in order.

The impeller isn't perfect, I find it hard to get programs perfect the first time around, but I never intend to make another one of these and it is good enough. Stock impeller on the side for comparison.

(https://i.imgur.com/f74kjIK.jpeg)

Nice! I hope this takes care of the temperature problems.

Fingers crossed!

Between this and the extra inline radiators we are hopeful. We weren't that far off, just marginally so. An overheat is an overheat though. On regular race tracks the car sits on the thermostat basically, so we are over cooled for anything with a decent average speed.

We reworked all the "tube nuts" on the head as well. There is a lot of interference of the nuts against the head and cylinder and as a result there is no way they achieve accurate torque with the torque wrench. So it is clear some of the lacking ability to hold water pressure is related to that. That said, we don't want to over heat at all.

I had hoped to machine the new cover yesterday but the F1 race was a real blast and the F1 watch group in Pittsburgh ended up being a little too fun. So I made some ribs and hung out instead.

I got the soft jaws machined and the side A on the pump cover machined yesterday. Everything is going to plan. I just need an hour or so to do side B and the cover is done.

Dave (my father) continues to chug away at the conversion of the Express into the Grumman body, I don't see anyway we will have it even drivable for the Grand Prix in July. Dave says otherwise. The best part is that the fuel return line was rotten and was just dumping fuel onto the ground while driving, most of the steel fuel lines need replaced. It's 2008 that we bought new and maintained well... Or so we thought.

The Express is body-less and the Grumman body is getting fitted in various small bits. We adjusted the motor mounts to change the transmission angle slightly, worked on rearranging the radiator and intake, lowered the fuel tank, and are working on fitting a different exhaust. It is an interesting conversion to say the least, something we aren't exactly well versed in. One pic below, it really shows what is the base of the Express and what will be the underpinnings of the Grumman. I am working on arranging tow vehicles for the season...

New Triumph (larger volume) brake calipers are going on the race car and we rearranged the pedal ratio as well, in part thanks to some information we reviewed here on the forum. I could lock them up, but the pedal was woody as all get out, not great. We have a good 10 seconds just in squishing brake zones into appropriate distances at the PVGP track. Then there is another few seconds in better tires, better carburation, better driving, and of course a lack of overheating (it better f'ing be solved). We will probably go way faster and then break something new every session, lol. According to the data, if we can realize these improvements, we will easily reset the all time lap record. According to reality, it will be hard work.

(https://i.imgur.com/pEF2nAw.jpeg)

(https://i.imgur.com/Hz2kPR7.jpeg)

Job well done on this cover, I reckon. It will be on the car at the bottom of the engine, above a sub frame, and will be seen in 3 years when we need to take it off again. lol

(https://i.imgur.com/uyGPxvn.jpeg)

I got a call from my dad a bit ago. The left rear brake line fell off the Express when he was trying to drive it under the Grumman body. The Grumman body is currently suspended on a 4x4 frame in my father's yard, and since the Express weighs nothing without the body and all of the interior the thing was just spinning the rear tires with the open diff. Well, the traction control apparently kicked in and blew the brake line when it was attempting some sort of stability control or god knows what. He drug it under the Grumman with his Kabota tractor. He thinks the body is going to fit, but the passenger side front seat is iffy because the door is there. He's determined to at a minimum have the body fitted and the vehicle drivable by July, as to tow to the Grand Prix. Pretty optimistic I'd say.

We will see though.

The body and chassis work perfectly. The Grumman is all together. Dave says he needs to weld in various attachments and remove the body once more. Even if the Grumman van isn't complete it will tow.

For the race car I've ordered tires, we fitted the new brakes, and have adjusted the brake pedal motion ratio. Let's hope we gain. Proper testing sessions are looking less likely with the tow vehicle still underway. I have several formula car events as well as trans am events in the meantime. It will negatively change our testing but positively change our budget. Not sure how I feel about it all. I need to get a few karting days in to bone up on my decrepit driving.

Anyways, we push on.

We haven't spent a lot of time on the car, but we have done a few small things. I've got the head and am going to change the squish a bit. We will lose a bit compression but we were slightly higher than we wanted anyways. We aren't a 100% sure we didn't hurt the engine last year, but we've decided to run it as is. If she blows, she blows. We are thinking we may have stretched the rods, but without a full tear down it is tough to tell. We know the squish got smaller, so... With the overheat maybe the gaskets settled, or an over-rev made the rods get a bit longer. We will adjust the squish on the mill to get it back to where it should be and hope for the best.

The new brakes are on, the pedal feels like it will actually work and modulate, but time will tell. I have been hunting for tires for this thing, hard to find as we use odd wheel sizes. They also have to be grooved as it is a vintage car, making it more complicated. I am hoping I can swing a set. I had a bit of a set back with my business and lost several grand of what would be funding for this program just in last 10 days. So I am trying to work on that and produce some replacement revenue. Also, finding a decent medium Special Applications 2020 helmet has proven difficult. I ended up buying an Arai, which traditionally are my favorite lids, but the wait times puts delivery for the helmet at the Monday after the races have concluded. Fingers crossed they deliver a few days early.

The Kerbside isn't even close to being done, however, it is road worthy! State inspection to get done in the next week or two. All the inspection required items are good to pass. So once the plates show we will take it for inspection. We registered it as the Chevy Express as that is the vin on the chassis. Let's hope we don't get too much hassle at the inspection station.

The windshield is out in these photos as we were finalizing the windshield wipers. It will use the Express wipers hung from above. We hope to park the wipers vertically, but we aren't sure we can do that just yet. They may end up horizontal at the top when parked, it just depends on what trickery we can do with the existing setup. The nice thing about the Express wipers is that they tie into the Express controls, so we will end up with modern wipers in addition to the modern chassis. For a while we were thinking we would just tie in the old wipers with a toggle switch, but now we are spoiled with delays and speed adjustments.

(https://i.imgur.com/0vwtO2S.jpeg)
(https://i.imgur.com/waj1FVa.jpeg)
(https://i.imgur.com/p5DbypT.jpeg)

that thing is straight up bitchin.  :eek: :olaf:

Thanks! It's been quite a project. The entire front clip comes off because that's the only way to service the drivetrain. It is tight under there. We tilted and lowered the entire drive train to fit it, and we had to rework all of the fuel system, exhaust, and various accessories. The hvac does not work at this point, lol. Windows down for the summer trips, hopefully no winter trips until the hvac works again. It drives like shit unless we have a trailer on it. It is sooo much lighter at this point, based on ride height we are guessing about 4000lbs, meaning 2000 lbs. lost give or take. It is way over sprung for normal operation. Of course some interior will help with that, but we aren't there yet.

I forgot to mention we finished up the half shafts for the race car. I wanted to make some really neat large OD aluminum shafts but my old man nixed that. He turned them out of some nice thick wall stress proof steel and welded them all up. They should be way overbuilt, not exactly what we want with a 1000lbs. race car, but Dave does what Dave wants. At this point I am in no position to argue. I will have the head machined today or tomorrow. I finished the programming last night. We assemble the motor Saturday. I just hope I can get us tires in the meantime.

We have had a bit of a change in philosophy on the cylinder and head. As mentioned we aren't too sure why the squish reduced. It didn't change much but any change is odd. I touched up the squishes changing the squish angle 2 degrees on the inner half of the piston to make the squish diverge from the piston crown a bit. Getting this setup was tricky. It relied on the fixtures from 2.5 years ago, me remembering how they all worked, and then just fudging stuff around until I was able to just touch the squish. 2 degrees at that width meant about .008" of material at the corner of the squish. Not much, but just what we want to see on the solder. We are going to do another head for sure.

(https://i.imgur.com/392GHV9.jpeg)

Then we threw some pockets on the water passages for o-rings. This allows use to energize the gaskets from both the bottom end upwards, and top end downwards. We hope we eliminate any potential sealing issues there. We think we had a minor leak there.

(https://i.imgur.com/ENNOXdc.jpeg)

The top end is now on the motor. We will pressure test it soon. We found a crack in there rear tripod that carries the spool and bits for the chain tension and drive train. That will come off for repair. We also started replacing rear rod ends. At least 6 of which were in bad shape.

Things are coming along well!

They say if you aren't breaking things, you aren't pushing hard enough. Sounds like you are getting there.

Well, this will be try 3 with this car at the Grand Prix, and year 4 developmentally as we missed '20 due to COVID.

They say third time is a charm, but historically we have been excellent at breaking things. Maybe if we have a bunch of applicable sayings we will convince ourselves into success. I'm not sure if we are getting to the point where things are sorted or if we are going to go faster and just break more shit?

Anyways, the new inline coolers are in the pods. I finally got the dash setup so I am hoping for data this time. I just need some corner velocities to look at so I can work on my driving. That's all I ask.

Tires remain the big hold out. The rest of the pieces are falling into place. I am going to look into tire treatments. They are very common on dirt tracks and there are a ton of dirt tracks around. These tires look okay, but there's no way we don't have several seconds per lap to gain in a new set. They are just hard to find. Apparently Avon is having troubles getting rubber from Ukraine... Great.

Keep in mind the lap record is a 2:09 or something like that. A two minute lap time in modern racing is big, Le Mans being perhaps the standout with 3:15 laps, but most of it is just straights. This street circuit is almost all turns.

We got the spool welded up yesterday. What an ugly old bastard this thing is. There is massive force on this thing as a result of chain pull which is why it failed three or four times before this one. The single inboard rear brake also hangs on this thing, so I guess it gets punished doubly. It's one of the more challenging engineering parts on the car. The grade of aluminum certainly has been degraded due to being welded on like 12 times, so we decided to go one step further this round. We made a make shift oven out of oven bricks we had laying around as a result of us building an earth oven. Using some torches we heated the spool to around 1000F for about 40 minutes, then quenched it. It will age naturally for 3 days then it goes in the real oven (yep, the one the kitchen) at 425F for 24 hours. Hopefully this restores the temper.  While were at it, I modeled the entire the entire setup and will be prepared to machine one out of billet. Probably a bolted plate situation but I am not worried about it now.

(https://i.imgur.com/fVWxGVE.jpeg)

We finished the new half shafts too. That was kind of fun. We had the half shafts in the lathe, with the lathe well covered in wet rags to protect it from splatter, we got the ends nice and true with the new collars in the middle, then Dave zapped them with the MIG machine while I manually turned the lathe in some attempt to match the weld speed as the beads went down. They actually turned out great, but that was a bit of a new process for us. Unfortunately I didn't take any photos. After they were welded we cleaned them with the lathe. They look great! The beads are massive compared to the old setup, looking good!

Dave also went all in on rod ends. Nearly $500 worth for the rear of the car, and we aren't even replacing all of them. Trailing link suspension really is a pain in the ass. That said, the rear steer issue should be gone. If we have a bump steer issue it is going to get worse... We have a month to go on prep, we will probably spend several days just going over rear geometry.

The Kurbside is basically functional. Dave got the windows in, then took them out, then started messing with the windshield wipers again. It looks exactly as it does in the previous photo. However, the remote adjustable mirrors are now mounted and working. lol. All it needs to do is tow the trailer 100 miles. Fingers crossed.

I wish I had grabbed a photo of the spool setup from the opposite side. It's hard to tell what is going on there. That fabricated box is completely hollow. The axle runs through the center and accommodates the sprocket, chain tensioning parts, rear brake, and all the half shaft bits. It all swings on the top pivot (show in picture) and has two links that are adjustable at the bottom to tension the chain. The broken section is where you can see the bit of grinding, although the crack extended to the side not seen in the photo.

I spoke to my father on the phone today and he figured the car is worth about $400 in scrap. He's not sure if he should turn it in or not. lol. It's hard to get a read on peoples sense of humor on the internet, but that is definitely him joking around.

Well, we are two weeks out and are basically ready to go.

We ended up replacing a ton of the rear rod ends. It is way better. We various modifications and adjustments, but the car went on the pad and scaled out basically perfect without much messing around. The van is together, it tows the trailer. We have a few issues with the lights. The rights don't work at all on the trailer when connected, the lets are fine. Probably a plug issue.

Pictures of the car on the "pad", the new tow setup, inline rads, and some puppers along the way;

(https://i.imgur.com/XGfVlfB.jpeg)

(https://i.imgur.com/LoKRo2O.jpeg)

(https://i.imgur.com/Lnno7AZ.jpeg)

(https://i.imgur.com/fTyvFyR.jpeg)

(https://i.imgur.com/zTiHuUT.jpeg)

(https://i.imgur.com/c5WijWM.jpeg)

So, which one is the engine tuner, and which the chassis expert? This looks like so much fun! Hope it holds together well and brings home some trophies for you.

Both are experts in eating leftovers and getting spoiled, not much else.

This year we are hoping the car doesn't break every session. We have picked through so many of the little hang ups, but every time we go faster we find another weak point. I honestly might just baby the thing through the first three sessions and then give it hard thrashing in the race and hope for the best.

We ran a pressure test on the engine yesterday, all good there. We let it idle for an hour, once the thermostat cracked at 210F and the rads warmed, it then sat at 170F for a good 40 minutes. No leaks, no drips, and when we popped the cap it was pressurized still. I think we might have the cooling issues worked out with the bigger impeller and extra rads. That is certainly the coolest the engine has been especially considering there is no active cooling, it relies on being driven to force air through the cooling. With some luck we might have finally got the cooling efficiency to where it needs to be.

I didn't grab any photos, but there isn't much of interest to see.

I spent a good part of the day cleaning the car. My father worked on tires prepping them for treatment. The car looks just about as good as a 45 year old car that we have tried pretty hard to keep reasonably original lol.

The car is in great shape mechanically. I think the best prepped it has ever been. Which of course is always the goal, but time, money, focus, willpower, it all varies. We did a nice job this year. It is a shame we never got on track beforehand, but we took our knowledge from the last few years and got it together. There has been many changes, most of them refinements. The development while slow and tedious is about right. I have a good feeling about this one.

We load in on Friday. I will grab photos and be back to report in.

Refinements is where I like  to see things change. It isn't often (you have to be way off) that a "swing for the fence" change works out. Often just a small change makes a big difference. Important for reliability, as it is an indication that things are staying pretty close to where you set them.

I agree. Progress is incremental usually. It is hard to be a revolutionary.

Everything is officially in order for the race. As usual, I got a talking to before the race even starts.

Every single year there is some hang up with my entry by the governing board. The guy who runs the organization really does not like me. I've only met a few of the members here on this board in real life, but I would consider myself a pretty fun and loving person. I'm not mean or malicious, I just like to race.

I got an email on Monday from the governing board that my license and medical evaluation weren't valid. I hold an SCCA Pro license, with a medical evaluation that is good until 2024. That information was submitted with my entry. If you aren't familiar with car racing licensing, an SCCA Pro license is basically the king of licenses in North America. It works in Canada, it works in Central and South America, the only license that would be better is an FIA License. North America doesn't really use the FIA so there's no need for it. Though at one time I carried an FIA license. I could enter a 1000hp TransAm car and nobody would question my license. It is basically a passport to drive in any race. The exception being the Indy 500.

After two days of emails and phone calls they have finally, officially, allowed my entry into the race. Mind you the entry fee was already paid. They have said that my license will be accepted this year, but next year I need to buy their license. For a total fee of $25... paid by check only. Sigh.

I have had my SCCA Pro license since 2009, it was totally acceptable to use it for entry into the PVGP since my first entry in 2015. This year, the highest license in North America isn't good enough, but they let me slide.

I can only laugh about it. There is just nothing else I can do.

accidental double post on this.

Sounds like they are bucking to be FIA regulators.

I don't know if it is that they just genuinely have it out for me for some unknown reason, or if they just like to hassle people to gain some sort of power or ego boost? It is completely ridiculous though. We are racing cars for charity, my licensing far exceeds what I need for the event, and on top of that this is my 6th year competing in the event.

We made it! The car is there, the pit spot is setup, the brakes are bled, the engine starts. The clutch was iffy getting down to the parade, but it works well enough to ride around town. In the last photo you can see a yellow Porsche convertible top right. Poor guy got stuck behind me in the parade. Suffice it to say, my car loaded up early in the drive, he got the full 2t treatment.

Lou rode in the passenger seat (aka the space for the fuel cell and fire bottle) down the to the parade. At first he was completely terrified, then after a bit he loved it. The streets get lined with people that wave. There are police at the intersections. He got waved and enjoyed the race car experience for his first time.

(https://i.imgur.com/Tcf160I.jpeg)

(https://i.imgur.com/B5zR9dP.jpeg)

(https://i.imgur.com/LN55TFC.jpeg)

Well, we came, we saw, we didn't quite conquer.

We finished the first two sessions of the weekend. Whereas last year we never finished a session. A huge improvement. The first session we used as a shake down really. I eased everything up to temp and tried to watch temps and get a feel for the news brakes. The second session being qualifying, a clip fell off the needle and I was left with a pretty poor running engine as a result. Though I decided to continue on as to get some more seat time. It was an easy fix. We qualified in the back half of the field but with plenty of pace left on the table. The unfortunate thing is that I haven't had seat time this year and I could have really used that session.

On top of that, there was a huge storm that knocked down some trees and a telephone poles that evening. So they cancelled the Sunday warm up. That left just the race to get into the swing of things. Of course it was 95F, first real track time of the weekend and I had to drive the thing at some reasonable pace.

I got a nice start and moved up a few spots. By the end of the lap I managed to gain one more spot. Then I think one guy ahead me retired. I was starting to pick up the pace and passed one other guy. By this point the top two were long gone but I was third. I got a little pressure from behind but was gaining pace as my comfort grew. It was around lap 4 or 5, now about 15 minutes into the race, I was starting have some issues with front lock ups. So I dialed in some more rear bias. About one lap later the brake pedal went to the floor, I damn near crashed into the Jersey barrier on the exit of turn 1 but I collected it up.

I decided to carry on at a significantly reduced pace. Any finish is better than a DNF. As I cruised brake pressure slowly started to return. Water temp was high, but manageable. The nearby 4th place car then dropped out with a mechanical and I knew I had a massive gap behind so I really started babying it. Unfortunately on lap 9 the fuse on the ignition blew leaving me dead in the water, another podium lost. They completed 14 laps total. We aren't sure where the issue is, but obviously the fuse didn't blow because it was hot out.

There are a few takeaways here. 1) we are really close on cooling, it was marginal but functional. 2) more work on the brakes, probably a change in the rear brakes this time. A vented rotor and some sort of cooling. But also cooling for the fronts. 3) get rid of the fuse block, if the wires burn they burn. 4) a test session or two and some new tires for next year are needed. 5) figure out the cooling on the Van.

I think the car might have a bad damper as well, but we didn't investigate. I'd like to go to a new set of dampers, but Dave wants the Ikons.

Finally, my camera didn't record so I didn't any on track video. Pretty bummed about that. Luckily the track was rather slow this year. So it isn't really comparable to other years, nobody got within 3 seconds of their personal bests. It was too hot, to greasy.

Anyways, this will probably be the last update for a while. My father is completely burnt out, I am pretty burnt out, and we both need to mow our lawns and do work that pertains to everyday life.

Once I get my photos sorted I'll post if there is anything worth seeing.

Glad to see you finally got some quality seat time, it was a tough weekend to be racing. 

That track is always going to be hard on brakes and cooling systems, lots of elevation and stop and go. 95 degrees doesnt help either.  Might need to do things differently just for that track.

Good luck finding the short, hopefully its not in an expensive place.  You'll find it, there cant be too many wires on that thing:)

Heat may have been a factor if you are running points and the primary is on the stator, wires and coils only like to be so hot and vintage enamel might melt when the motor is really soaked out.  You being water cooled makes me think its unlikely but I dont know those engines at all, I'm sure it wasnt cool behind the flywheel Sunday.

It was really nice meeting you! Make sure to come and hang out next year!

It has a Pertonix based ignition. Heat may have been a factor, but who knows? In a month once we feel willing to look at it all again we will assess.

You might consider reset-able circuit breakers that you can reach in the cockpit. Burning a wire isn't too bad. You don't want it to burn down the while car!

We had that discussion after the race. Either auto reset breakers or a second ignition circuit with a second ignition switch. The latter being common in stock car racing. We have a while to think about it.

My guess is that we will chase the wires, fix the chaffing or whatever, thereby correcting root cause. Hopefully then we will never have the issue again. As Clem says, there isn't much there to look at.

Typically in race cars you let the wires burn and if there is fire you pop the bottle and hope for the best. This is very common race cars, the only race car that I have ever driven that had fuses is this one. Keep in mind there is literally one of these cars. So my father has been a bit more cautious with it. Of the many professionally built race cars I have driven, where you get many spares should you need them, there isn't a fuse on the thing. But they also have wiring looms designed and braided by professionals.

Anyways, I think after a week or so we will feel a little less deflated. We were truly close this year with most things going our way and yet another gremlin emerged. The game of whack a mole continues.

Complete 2nd set of ignition system is also common in aviation and it really shouldnt add much weight.  I could put you in touch with a guy in E. Liverpool that builds his own frequently if it will help.  Also, I think its been tested that dual plugs make more power. 

Really shouldnt be necessary though, I'm thinkin you'll find something simple and obvious once you see it.

Good luck, more fun to drive em but good fun working on them as well:)

We pulled the head yesterday just to do some analysis of the engine condition. That lost needle circlip did just about as much damage as a circlip can do. Certainly not terminal but the head took a nice mashing. The ports look clean on initial inspection. We were planning on a new head anyways, so we aren't gutted about it. The piston seemed to survive without much damage at all. I guess that is one benefit of that soft Suzuki aluminum.

I shattered the rings on an SBC in a race once.  It's amazing how metal can imbed itself into things while simultaneously bouncing around like shot peen.