dr bob

John-

That looks like a nice ~~900kW fuse. Swap for a slo-blo and see if it still blows in your service.


Considering the other available failure modes (driveshaft. Gearbox input shaft. Etc.) this is not so bad.

John Veninger

We'll that shaft survived the last 3 years behind the stroker motor. Guess the 500+ft-lbs of torque to the 335 Hoosiers has put a lot of stress on it. The new shaft on its way from Anderson so I can get it in before the Lime Rock Race this Friday. Glad he had a new one since there are 7 in Germany, not in the US. Was ready to drop the clutch on the GT to make the race.

I was told that JB weld doesn't really work to well on that part

I was SO SO glad it was the shaft and not the transmission!

terry gt

wow! one more vote for an auto box

Fabio421

You know, I hadn't thought of it that way intil you mentioned it. Maybe it's best to leave that part as designed.

djurek

The weakest link.

karl ruiter

I hope the supply of those shafts does not dry up. I heard they were getting harder to get.

Lizard928

I have a brand new one sitting at home waiting...

As to if supply dies up that can be reproduced at reasonable cost

John Veninger

So I broke the central shaft last Thursday. 928Intl is getting me one by Tuesday so I can make the Lime Rock race this Friday.

I was preparing the car for the race on Sunday and noticed a puddle of oil under the front left of the car.
Jack it up and see my custom valved solid mounted bilstein shock blew out

3 weeks to get another one and 2 weeks at a min. for a rebuild.
They are B46-0204OR

A Koni would be a 3012-1630

Travel=5"
Ext=16.25"
Comp=11.25"
1/2" uniball
2.5" spring perch

Suggestions?

Fabio421

PM sent

John Veninger

Thanks Shawn. Looks like they may have something that will work. Don't know if they will be long term on the race car.

mark kibort

glad the "fuse" blew and not the 5th gear. Lucky you . I dont think its the torque of the engine, as I blew a 5th gear on my 5 liter at 290ft-lbs of torque. I think it was due to the dyno run with the ebrake partially on creating a real bad vibration. when the ebrake was released, the run was 50ft-lbs better, no vibration adn then.........Wiiiiiiinnnnnnnnggggggggggg to the rev limiter, oh, no rev limiter, but caught it quickly enough. 5th gear broke just like this part.

That part should easily take the forces of 500ftlbs, but how you shift might be part of it, expecially if you have the new updated clutch system, which you do.
Think about it.... now the clutch has 3-4x the clamping force, no margin for error. you drop the clutch, the drive shaft has to wind up, but the force is instantly at the short shaft, and breaks BEFORE the rear shaft can wind up and apply the torque to the 5th gear. Now, every wham Bang shift, is going to give new meaning to "force" at those parts. Im pushing around 420rwT and havent had any issues, and if you are shifting really high in the revs, you could move out of that peak torque area. Try shifting at 7000rpm

As far as the shock goes, there is a shop in Napa that rebuilds the shocks, mostly Konis I think. might be worth a call. Im sure he could meet your deadline. He quoted me rebuilding for my 12 year old konis and was confident he could turn it around quickly. Now that my racing budget is gone, Im just dealing with stuff that is not quite up to par, but still working.

Best of luck at limerock. Look for that 1:57!

mk

John Veninger

A 1:57? It would have to be pouring rain or using my Dodge Diesel truck to get that time.
A 58 is more like it.

Mike Frye

Dayum!

John, I've got to hand it to you. You have a gift for pushing your car to the limit and finding the 'weakest link'. So as of right now, you're one of only three people known to have done this. Impressive!

Good luck this season, I hope to catch you at one of your races again this year. Keep us posted.

John Veninger

Thanks Mike. Now we know why auto manufactures race......

Mike Frye

Seriously. And why parts manufacturers sponsor!

I wonder what kind of torque it took to do that?

Also, would it be from the winding up or from a combination of winding up and lifting off the throttle (when presumably the trans would be driving the engine or 'engine braking')?

That is amazing. You need to keep all of these 'race tested' parts and make a display out of them.

I wonder if an i-shaft could be designed with the equivalent of a shear pin to protect the drive shaft. Maybe something you could replace by just dropping the bell housing at the track...
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Porken!?!?