Hello and Happy new year to all. I just picked up a really nice 1992 c4 w/80k miles that has a horrible clutch chatter/shudder when trying to get going in 1st or reverse. The clutch has been changed atleast twice in its very recent history. It has a Carolina Clutch stage 2 kit in it from what I was told. I'm about to put this on the lift and break this sweetheart down for a inspection. I'm expecting to see some heat spots on the flywheel and hopefully a chineese Valeo that has the poorly casted legs. I've been researching this issue extensively and am considering going to the ram clutch push style because it appears to be a matched and balanced, made in house set. The directions explain that the clutch and flywheel come bolted together, the orientation is marked and should go in exactly as it is shipped. My other option is to leave the pull style system, replace the spec fly wheel that is in it with the extra mass flywheel they offer and have my Pressure plate machined to fit and balanced with that fly wheel. Any suggestions on getting this car drivable again would be greatly appreciated. I'm just trying to save her from the weed field (thats how bad it is). Is ther another pull type "matched set out there that I haven't found? seems to me Ram is the only ones offering an in house USA made assembly that is a matched/balanced set, and its only offered in push style. I'm also wondering what the benefit of the push style is and why Ram decided to go to this style. Thankyou in advance.

 

The problem with staying with pull-style setups is really that you can't buy a quality throwout bearing for them anymore. It used to be that OE replacements from the US or Brazil were actually good, but there are only Chinese ones available now (regardless of brand they all come from the same factory) and they are awful. I believe you can get the pull-style pressure plate and disc to work well, at least with an organic disc (which I think your CC Stage 2 kit includes), but the TOB will always be failure mode. That's a shame, because that means all the ZF6 applications are in that boat.

AFAIK, the RAM push-style swap has the market cornered on a ready-made kit to make this changeover. Although they take extra work to install, I've seen good results reported from those who have done the job.

 

I just wrapped up a RAM conversion - with a test drive this afternoon. Used the steel flywheel and basic street disk.

I did a Carolina complete stock change last year with a new MC and Slave. Tried to buy stock OEM equivalents.

Clutch started chattering horribly in the summer.

I was expecting to find heat spots but surprise - Chinese quality. The throw out bearing failed. The inside of the bearing started spinning on the outside of the input shaft collar. It gauled the collar as it moved and spun on the sleeve.

The RAM is very smooth and easy with engagement nearly on the floor. The clutch actually feels like my S2000.

Installation had its challenges.

What I noticed so far was I cannot cruise at 45 mph in 6th anymore. I get a little shuddering, maybe the new flywheel is lighter. 65 mph seems to be where I need to engage 6th now. My mpg will suffer but I gain more smiles per mile.

I did install the thicker shim which was a project unto its own. At idle I don’t notice any difference than before. I’ll call that success.

Anyway, the RAM conversion is the way to go.

 

did u have to replace the collar ?

 

What are your cam specs and rear gearing? I had a 396 LT4 with some moderate overlap to the cam (I think you've seen other posts about it) and a 13lb Fidanza aluminum flywheel running stock 3.45 rear gears. I was able to use 6th at 55mph without any bucking. With a heavier flywheel, I would expect you to be able to at least go as low in 6th as I could (but this depends on your cam and tuning). That said, these cars are geared so tall in 6th that I don't think it makes sense to use that gear except on freeways/highways.

 

I did not replace the collar. The slave/throwout bearing for the RAM conversion slid over the collar as an assembly. The RAM system presented a perfect solution for me. After a 30 miles test drive, I can live with it.

Vette is all stock, 1993 Z07.
42,000 miles


New RAM slave hydraulic throw out bearing combo which slides over the input shaft collar. The fit was very tight, which was a PITA during assy - pushed the assembly on to the collar us g the PP fingers.

Shims are visible. I used all provided and was around 0.190”

Pic shows uncut locating pin

The travel for the throw out bearing is the length on the inner assembly sleeve (bronze color). The bearing is replaceable. I read the hydraulics is rebuildable. I don’t plan to do this again.




Input shaft collar damage. Didn’t want to install another crappy pull type throw out bearing and possibly completely ruin the sleeve. Didn’t want to install a new sleeve and risk it leaking trans fluid of it being damaged again from crappy products.

 

Hmmm. With a stock engine and steel (heavier than I had) flywheel, you ought to at least be able to pull 6th at 55mph without any drama, like I could. I can't think of any other factor related to the conversion that should affect this.

 

I’m gonna try again.

Could have been bad fuel, car has not been driven since July when the clutch failed while making some passes down the quarter.

I did find the vac line to the opti was off. must have off when I took off the intake from the air cleaner assy.

it was surging some so magi by have been the vac line. Vac leaks will cause strange things.

I will drive it next week to work with some fresh high test and double check vac lines.

 

Update:
After a 20 mile drive today with the windows up, significant more gear whine. At idle, nothing more than before unless blip the throttle then it sounds like a bunch of rocks in a tin can being shaken.

It will handle 55 in 6th but it makes a lot of gear shatter. No vibration, maybe it was the road or tires (car has been sitting since July-August) and vacuum line off.. At 60 and 65 in 6th, no issues.

The RAM clutch engagement point is about 2/3 down. Nice and easy with Honda S2000 smooth like engagement. Very happy with the RAM conversion.

I’ll be trying to source the input shaft collar and the next owner, 3rd, will have the opportunity to go back to original as the DMF is still good.

 

Okay, good. You can't really do much more about the rattling. The main thing is that the engine is running properly. I would say 60mph is the lowest anybody should try to use 6th anywya with 3.45 axle ratio.