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Clutch chatter

2K views 5 replies 4 participants last post by  western star 
#1 ·
I have a 1980 Camaro Z28 - 350 - w/4 speed all in factory original condition. The problem...my clutch chatters badly on first gear clutch release and mainly when on an incline. History - engine professionally overhauled, differential professionally overhauled, transmission dito, front and rear suspension completely overhauled, all clucth components new including z-bar, clutch fork and pivot ball on bell housing, matched clutch kit (actually third one) and new GM flywheel (which was even turned to spec) and the chatter persist. All tranny/clutch work being done by professional tranny shop. What is the deal? My mechanic is determined to make the repair but we're both puzzeld.
HELP ME PLEASE - ANYONE????
 
#2 ·
I would check the pilot bearing/bushing in the end of the crankshaft and the shaft size that fits into it. If there is excessive wear on either or some on both, you will get chatter. If left unchecked, you willl damage the interior bearings on your transmission input shaft. The bearing/bushing in the end of the crankshaft is a press fit and it can be loose in the crank, causing the same problem.

Trees
 
#3 ·
I feel for you. I hate problems like this especially when you've replaced everything with new parts. I would be thinking that maybe I had a bad pressure plate. Something else you may want to try. Put a torgue strap on the front passenger side of the motor and fasten it to you frame to see if your engine mounts aren't doing their job. Do you have a hydrolic clutch? Maybe it's not releasing properly. We have had this problem in larger trucks where the clutch becomes jumpy on release. What make and model clutch are you using? Just thoughts but you have to consider everything. Good luck.
 
#4 ·
Have you checked the crank centerline to bellhousing centerline. Too much offset creates problems. You can have offset even with new parts. Have someone dial indicate this and iff needed use offset dowels.
In heavy trucks(not pickups) at work we have the flywheels turned on a lathe and not on a flywheel grinder. A lathe produces a truley flat surface parallel to the crank mounting flange. The very best flywheel grinder produces a slight concave surface prohibiting complete clutch disc contact. Check this with a machinests straight edge. We have found this to eliminate a lot of clutch chatter and poor release problems.
Also make sure the trans. input shaft splines are in excellent condition. The disc has to move on these when engaging and releasing,even though the movement is very miniumal.
 
#5 ·
Thanks for the suggestions. The pilot bearing is new and the fit has been determined to be perfect. The end play on the crankshaft is .006 and normal is .004-.006. The GM flywheel has been turned on a lathe and actually it was turned with a slight campher (?spelling) to it which my mechanic said was correct procedure. I've thought about the engine torque and strap but when I put the engine back in, the engine mounts were replaced as was the trans mount bushing. I only had my engine pumped up to a 350 HP by virtue of pistons and cam. Nothing radical so I really haven't made a big performer out of it. The trans imput shaft was removed and checked for trueness and also the condition....all checked out okay. I'll ask my mechanic about the crank centerline to bellhousing centerline and see if that has been a consideration for him to check out. The mystery continues!
 
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