Houston, we have a problem...

[Jim Nelson]

Anyone know any good gear makers? Ron? CJ? Vic?

[C J Murray]

JB Weld? Vic has gears for everything from the Model T to the Diamond Reo.

[Jim Nelson]

gearbox oil pump intermediate gear…..not sure the JB Weld fix is where we want to go. What you can't see is the other side, where (since the tooth wedged itself into the mesh, stopping the works) the end of the starter shaft broke clean off. I've managed to locate those since breakage was apparently not uncommon, but the intermediate gear I have on the way "has a mark" on it, and I don't know what that means. Replacing it makes the most sense.

I think they had a murder/suicide pact.

[C J Murray]

what vehicle? No, I didn't think epoxy would work!

[Jim Nelson]

Here's a look at the back. Plug the starter into the rear gearbox cover where the little hole is. Gear on first post is right inside the cover.

[C J Murray]

Why didn't you say so, I have one of those!

[Jim Nelson]

That makes it even easier, if you have one of these, I have some spares to trade you !

[Jon Bunin]

Jim,

Is the transmission based on a Hewland, but developed by Tyrrell?
The pump drive doesn't appear similar to an FT/FG, but might be based on other Hewland parts available at the time.
Diagram below is the oil pump for a Can-Am Hewland LG transmission.
It would be worth inquiring at Hewland with a photo and specs, if you haven't already.

Otherwise I would suggest contacting Phil Reilly, Hall & Hall or others doing F1 car restorations, for an opinion or further contacts.

[Jim Nelson]

Thanks for the reply, Jon, I believe there is also a variation of the FT that is for endurance cars that uses the drive gear for this pump, and possibly this intermediate gear. It's also possible, I'm told, that there is a derivative of the DG that'll work. I've already been to Hewland and their classic gearbox joint venture, PDS Racing, and they have no idea what I'm talking about. The folks who used to maintain the cars for Everyman Racing (Drive a Formula One Car !) in the UK are where I'm getting the new starter sprocket from; they had to have some made up, as these apparently had to be held to a fairly strict life. It's a little like reverse gear in one of these--you can use it, maybe once--its teeny.

Here is the "normal FT", it uses an oil pump as well. The drive gear (far right--the one that looks like it's lightened) looks pretty close to my drive gear, which is driven by the gear with the broken tooth, but there's other stuff as well. Duplicating the gear as well as the shaft (which is on the way) should do the trick. Can't really start it without these things.

And yes, the Tyrrells used their own case with Hewland internals, almost all FT equipment.

We've had the car since 1996, run it quite a bit in private, and this is the first gearbox issue we've had. Might try Webster, they made up some first gears on the shaft for us. There is an inquiry in the UK we're pursuing as well. When I was looking for a DFZ for this long ago, I was fairly rudely told that I should try someone else, as he wouldn't help (Reilly's secretary). I thought Wow ! I'd never even met the guy, and it sounded personal. So my engine came from John Nicholson, who is a prince of a man, just a great guy.

[Jon Bunin]

Jim,

I had several customers with old Formula 1 cars in the 80's and 90's, and ran (maintained) a '74 McLaren M23 for ten years.
Photo of me about 20 years ago with Mark de Paola's '82 March 821, after rebuilding the transmission.

Almost all British F1 cars in the DFV/DFY era used Hewland FG-based transmissions, which combined FT gears with LG differentials.
I believe your Tyrrells were the next generation of 3.5 liter cars, from '87-on, with which I'm not really familiar.

[Jim Nelson]

Great stuff, Jon, no question these are a lot of fun, both to work on and to drive. As I get older, tho, I feel like I've been in a brawl, they do beat you up. Best part is the brakes, OMG….

[Ron LaDow]

Jim,
I had new axles made for the March a *long* time ago. The splines are volutes; gear tooth forms. A guy in LA turned the axles, gun-drilled them and cut the 'gear teeth', so someone is (was?) in that business.
He was also (in the mid-90s) fairly well known among the F-1 runners; Jon?
I'd try a call to Phil Reilly's shop, or perhaps PRD Engineering ((707) 996-5852)
In both cases, they can be a bit prickly as you have found out, but it's worth a call.
BTW, contact me directly on this sort of stuff; I hardly ever check off-topic.

[Jon Bunin]

Ron, the only LA company that comes to mind for axles and driveline components is Metalore, in El Segundo?

I would first explore any possibility that this might be a standard Hewland item by contacting them, or perhaps Carl Haas.

I would then send an email with photos and dimensions to Reilly's for their opinion, or their recommendation for having some made.
Jim, it sounds like your previous experience was years ago, and never made it beyond the receptionist. I always found them all (Phil, Ivan, Ross, Chuck, etc) to be very friendly and helpful. Maybe Ron can help you with the inquiry?
I'm not familiar with PRD, but would also inquire there on Ron's suggestion.

[Jim Nelson]

Small progress. Now we have a good drive sprocket and a spare, but the idler gear is really no good, but makes a great template.