Projects Sprint Car - Clutch in a tight space

Hello everyone. I want to start a thread covering my next project, which is to get a clutch and starter into my Sprint Car. Firstly some background (apologies to those that have seen/heard this before...
I bought this car a few years ago on a bit of a whim, because I thought the look was right, it seemed honest, may have some history to it and I have a bit of the thing for Chevy and GMC straight 6 motors. I had no idea on value, but was happy enough with the deal.
The car had sat in a private collection in the Uk for 20 years. Having seen it at Hershey in 2000 a deal was struck with the seller, a Mr James Etter (Mr Etter was apparently a fairly prolific dealer from Pennsylvania?). Having got it back to the UK the owner never touched it again. There is very little paperwork, just a bill of sale and the customs declaration. The car was sold by Mr Etter as a 1937 Howard Johansen Sprint car. I suspect that was made up on the spot just to fill the box on the import paperwork!

It's a full size car. GMC engine looked to be a 270ci with some original race equipment, Scintilla mag, Howard intake, in-out box, Custom Quickchange, Buffalo knock off wheels with dirt tracker tyres, Stewart Warner gauges etc.

As I found it:





Fast forward about a year and we did some fiddling with the motor to get it to run. It's an in/out box with no flywheel, starter or clutch, so it was a case of push starting it in the yard to get it to run, which it did (and sounded awesome by the way). However, it also leaked like the proverbial seive!
So, we pulled it apart and got the motor up onto a stand. Inside we found 3.15/16" Venolia Pistons, a crank girdle and Isky LDB cam. So, at some point it may have been a fairly serious car (note the twin outlets on the radiator that have been soldered up indicate it may have been fitted with a flathead at some point in it's life? Head and block were skimmed, new gaskets etc and all put back together. In this pic you can see how rough the machining was on the deck of the engine (those lines are ridges).


I took it to Pendine sands for the annual VHRA hotrod races in 2022 and managed to do quite well with it. 108.76mph was my best run over the 1/16 mile...

All is good and it's a great car, but getting to the main point of my thread....... a push start only vehicle with no clutch or starter is a pretty limited use item, particularly here in the UK. Even setting up the engine is tricky.
Now I am coming to the end of my Model A build, I want to rip into the sprint car to see what can be done to improve on it's usability.

 

Here is what I have as a starting point...
Short torque tube mated to rear of the in/out box:


Drive plate on the rear of the crank:


Motor plate to mount rear of the motor to the firewall/frame:


Front end of the in/out box and 'bellhousing':


The in/out box is short and narrow!




Rear of in/out box showing UJ (I guess it's Ford?):

 

Tilton do 5.5” and 7.25” clutches so there is diameter there to fit.

How about a really outside the box thought; fluid coupling like used with Wilson pre-selectors, Daimlers, Lanchesters and some of the early US automatic gearboxes.

 

So, what I want to do is try and keep the dimensions like wheelbase and width the same, but find some way of getting a clutch and starter in there.
I can't move the motor forward any more than 1" and don't really want to put the weight any further forward anyway.
It doesn't look like there is much scope to shorten the torque tube more than 1" or so (unless you can see any way round that?).
As soon as I try to introduce a bellhousing in there, it's going to eat up any space for the gearbox, which is already very limited. Even the frame rails are narrow, meaning there could be some issues with fitting a full size bellhousing in there width-wise.

Here are my ideas so far (bear with me):
1. Centrifugal or torque converter style clutch, which would have to be mounted to a flywheel, I guess? Coupled to an in/out type arrangement, or even just a straight drive shaft to the rear end. That way I only have drive above a certain RPM?
2. Hand operated clutch with an over-centre arrangement meaning it can be disengaged and left disengaged. (I have a similar thing on my Caterpillar D2 tractor, but it's big and heavy).
3. Ask you guys for help (so here I am)!

Both these ideas skip over the starter issue, and I have considered all sorts of de-mountable starters that could drive of the front pulley, or be attached to the diff cover. However, I don't have any practical ideas on how to tackle this side of it either. The idea of a traditional style cranking handle is pretty much out because of the position of the radiator and grille. I tried to make a wheel drive starter, but without a clutch and due to the maths, it didn't get close to working.

Questions:
1. Is there a compact transmission setup out there that I could fit in?
2. Do any of my ideas have any merit or possibility of working (I have no idea on what components I would need to look at starting with)
3. Does anyone have any ideas to help me take a step in the right direction with this? I'm kind of stalled on it.

I would really appreciate any input.......

Thanks for reading this far,
Mark

 

Sorry I was typing my last post when you replied. That sounds an interesting avenue to explore. I’m not sure about how much torque they would stand, but will try to find out. Thanks

 

Daimler used a version of the fluid flywheel in their armoured cars. You find fluid couplings in some diesel trains too. I guess the size probably increases with torque capacity.

 

look into a bert transmission, very compact with an internal clutch, there are a few different models, some are very compact.

 

The USAC dirt champ cars all have some type of clutch. They have to be able to drive off from a stand still. One I looked at had a Crowerglide (centrifugal clutch) and an in and out box. However, the Crowerglide is not cheap. https://crower.com/clutches/complete.html

Many have a conventional clutch with an over center lever like you mentioned.

 

Look up the build that Marty Strode did for Pat Ganahl. I think they came up with a solution to the problem using a rare bellhousing and an old Ford trans. Might be a similar total length, and would bolt up to your torquetube.

https://www.jalopyjournal.com/forum/threads/spalding-bros-repro-for-too-tall-ganahl.983332/

 

They are multi disc, generally used in stock cars.

 

Not sure if you are looking for a clutch to race, or if you envision street use. When exploring your clutch options have a good talk with the clutch maker. The small Tilton 5.5" and 7.25" clutches mentioned don't tolerate much slipping of the clutch. They do have an 8.5" that is a bit more durable if you have the room.

 

http://www.berttransmission.com/product-category/transmission/
IIRC, before the Bert transmission, someone was using a Cone Clutch.
It may have been from a motorcycle.

 

http://www.berttransmission.com/product/bert-sprint-transmission/
and
http://www.berttransmission.com/product/dirt-modified-transmission-2nd-generation/

 

EMCO makes a small 2 speed for USAC Silver Crown cars.
They have to be self starting now.
https://www.emcogears.com/copy-of-ga46

 

108 mph in a 1/16 mile on sand?! Am I missing something or is that thing a fucking rocket?

 

Falcon has a shorty 2 speed trans:
https://wintersperformance.com/appl...5/Transmission__Drive_LineBellAll_Website.pdf

 

A friend of mine uses the Bert sprint car setup in his silver crown car. It works well and might be the best solution for the OP since it has low gear. A lot of the silver crown stuff uses a Tilton clutch and flywheel with a hand operated clutch, but that requires people pushing to get moving because it's direct drive. Those are typically on cars that use a Gerhardt starter (separate cart, shaft to the front of the crank).

Something more period correct would be a vintage Halibrand Indy roadster transmission, which is also a two speed. Would be a lot more difficult to source than the Bert setup.

 

Thanks Alchemy, I did see that thread some time ago and thought it might work, but the early Ford box is about 12” long without the bellhousing, so I shelved that idea.

 

It's not a drag race, it's speed over a measured distance. A Honda Accord could do the same.

 

I have looked at the Bert unit, but to be honest I failed to get any response or help when I contacted them. Maybe they thought because I am in the UK I was a waste of time. Shame because it looks great and does seem to tick all the boxes.
I like the idea of making something up that’s a bit more period, but to get all the components together and with all the trial and error there is likely to be, the costs are going to be pretty high I suspect.
I found a lovely little Riley pre-select gearbox on eBay like Oneball suggested, but it needs a rebuild and the seller is looking for £3,800, which gets me in very deep from the off. There is more in that area to explore for sure.
The Crower and Tilton parts all look pretty spendy as well.
I’m not looking to achieve street drivability, just a way to move from standing start to 1:1 lockup and be able to switch the motor off and restart it independently.
Thanks guys, I will study all your suggestions in more detail and update on my thoughts soon.

 

Yes, it’s a 1/2 mile run up (including my push start), followed by a time flying 1/16th of a mile

 

The car ran at Pendine Tim. We run half mile from a standing start then we are timed through the 1/16th traps. Marks car had to be pushed as mentioned and it wouldn't start until half way up the track so in fairness it is quick. If he can sort a clutch and run from the line I reckon we could well be talking rocket….its bloody quick!

 

lol forgot it was a trap speed situation when I saw 1/16. Still pretty damn fast!

 

This one is too long, but looking inside might give you some ideas.

 

You might find some Bert trans vids on youtube.

 

Ram made a clutch for USAC midgets about 25 years ago. I believe it was called a Ram coupler. It was basically a cone of clutch material that fit into a mating " flywheel". It was a failure in its application because no one wanted the weight of a starter and clutch. Having raced midgets, I would have marveled at how big your foot room is. By the way, your car is beautiful!

 

There have been a few sprint cars built for the street. Saw one in La Mesa (San Diego suburb) in the 90s. They had the same issue, don't FUBAR the car, extremely short length. I think they used a shorty powerglide. The width and starter coming back is going to be tough.
www.youtube.com/watch?v=cJr2vgD5jX4
www.youtube.com/watch?v=eIh_Kq3TreE
www.youtube.com/watch?v=VxpBSPu8qvI
This is the kind of thing that gets done in the midwest with old race cars. I'd try reaching out to places that buy and sell old racing stock and ask who does conversions. Then talk to them. A solution in England would be best and you all are known for your shed engineering, but if there is a setup that has already been proven and can ship over, it may be quicker/easier.

 

Riley used a conventional clutch with their pre-selectors.

 

You are probably going to have to use a Flex-Plate and a small diameter Multiple disc clutch.

However, most are for use with Chevrolet spline.

https://www.summitracing.com/parts/...MIkIuWqrKPhgMVnWhHAR2wGwotEAQYASABEgKJ1_D_BwE

https://ramclutches.com/product/937...MIkIuWqrKPhgMVnWhHAR2wGwotEAQYBiABEgK8b_D_BwE

 

I run a hand clutch on my single seater. No footroom to be had.