Flexplate Modification

[BB500]

I'm doing a lot of research on the whole flexplate/thrust bearing damage dilemma (as I think I have it) and can't help but to wonder if anyone or manufacture has maybe created a "less flexing" flex plate? Something that "won't" allow the shaft to drive forward into the engine?

If I had a garage I guarantee you I would be fabrication something...

[Danglerb]

Its not the flexplate, that just gives the system some compliance, its the pinch clamp slipping in just one direction. It seems to only happen with automatics, and early cars had a clip on torque tube shaft that prevented movement outside a limited range.

Three current solutions exist.
Check it annually, release tension, tighten the pinch clamp to spec.
Replace with the Constantine clamp.
Replace with the new Clamp from Roger.

[BB500]

Couldn't one machine a groove for a c-clip in the newer model's tube as well? I mean, is it really THAT simple???????????

[Danglerb]

Originally Posted by BB500

Couldn't one machine a groove for a c-clip in the newer model's tube as well? I mean, is it really THAT simple???????????

Thats conceptually simple, but in practice I suspect it would be expensive, this problem has been around for years and people looking at fixing it aren't stupid, so guessing its not done for a good reason.

Cheapest is going to be Rogers new fix, Constantines maybe the most proven.

[Landseer]

Not long enough, I think, if I understood Constantine correctly, compared to the circlip cars.

Three automatics at my house. All three had several mm of flex / movement to release originally.

I've got one car, 86, tightened down hard, without loctite, and its not wandering. 80,000 mi, .008 endplay. I check it every couple months.

I have one Constantine clamp, will put it on one of them, maybe the 84 that has the shaft to accept the circlip, but the circlip and shims are gone.

The third, 85, not sure what path to take. 71,000 mi / 6 Thou. endplay Key for me is to keep watching them.

[BB500]

Or maybe put TWO clamps on the shaft?

[lizard928s]

Dangler,

Your comment about the clamp only seeming to slip on the autos really cracked me up! The 5 speeds do NOT even have a clamp like this.

Beefing up the flexplate would actually make the problem worse.
As to adding a groove to the torque tube shaft to be able to add the circlip with spacers. It isnt an option on the later ones.

[Danglerb]

Thrust bearing failure has happened with a 5 spd hasn't it? Didn't know about clamp or not.

[BB500]

Ok Ok, new idea... If there was NO clamp, then that would be even better right? I mean, if the shaft slides forward, the flex plate would act like a shock and just push it right back, right?

[BB500]

Somebody sell me a 5 speed.

[Danglerb]

Originally Posted by BB500

Somebody sell me a 5 speed.

I have a 10 speed for sale, nice old Italian Lygie, might be good transportation until your projectitis settles down.

5 spd swap, $8k by the time its all done.

Constantine clamp, something like $300 I think, requires torque tube out, but that is almost certainly going to happen anyway.

Clamp research, open ended cost and time.

Pick the path you like, we have plenty of popcorn.

[lizard928s]

Mike,

There has been no actual recorded cases of thrus bearing failure on a manual 928.
They do not have the same type of clamping system. You cannot clamp the friction discs to the shaft as they need to slide abit.

[Imo000]

Originally Posted by lizard928s

Mike,

There has been no actual recorded cases of thrus bearing failure on a manual 928.
They do not have the same type of clamping system. You cannot clamp the friction discs to the shaft as they need to slide abit.

Actually there was, but it was a race car with a much stiffer pressure plate.

I think, and have been for a coupel of years, that a second clamp, from a donor car, is the easiest, cheapest and best solution to this problem. There is a prototype in the works (check rennlist) that uses this idea but in a slightly different way (a second clamp behind the factory one).