hey guys i am haveign a problem with my clutch disengageing. I have it down to 2 things, the clutch itself or the flywheel. now is there a minimum thickness on these things? I had it resurfaced once but it was really wavy and bad so i think they took a pretty lot off it. I am gonna pull the trans out again this weekend to measure how thick it is and get anew clutch and maybe a new flywheel if needed. so any info on this i woudl greatly appriciate. thanks in advance

 

come on some1 must know

 

does the back of the flywheel have a min thickness listed? I have a brand new GM 1986 - 1992 flywheel I can look at, but it's not at work; it's at home

 

The new thickness is usually 1.175" to 1.200". They make flywheel shims that go between the flywheel and crank in .025" and .050" to make up for the amount ground off. Check with a parts store like O'Riellys to get one.

 

The clutch bolts to the machined side of a flywheel. How does putting a shim between the flywheel and crank flange make up for what would be taken off after having the flywheel resurfaced? The shim would only move the flywheel/clutch assembly as a unit. Or has it been too long since I had mine apart?

 

It makes up for it because when you shave of some of the flywheel, you bring the clutch further away from the throwout bearing; true the hydraulic linkages are self adjusting, but it has a finite amount of adjusting it can do. The shims bring the whole assembly back so the distance between the throwout bearing and clutch fingers is within a tolerable distance. Then it should operate properly.

 

don't forget that as a flywheel gets thinner it is more prone to warping due to excess heat.

 

That's why it's probably better to get a new flywheel and not worry about it. It just depends what's more important: Money in your wallet or flywheel which may truly not be the root of your problem. But it's either that or the clutch.

 

By the way, nice looking 'bird.

 

I'll be honest, I've run two twice-surfaced flywheels and didn't use the shims and never had a problem. Once with 84-92 hydraulic setup, once with 83 mechanical stuff. One of the wheels was off a 91 Z28 and it had a shim behind it, but I ditched it.

Maybe I'm just lucky? Either way, a new 86-92 16lb wheel will be going in front of my T56

Uncle Skeletor - your avatar and name crack me up. Battle Kat and Castle Grayskull are no doubt at my folks house in the toybox somewhere.

Matthew

 

iv always heard the rule was the flywheel should only be resurfaced once and then you replace it.

 

If you like throwing away perfectly good flywheels, yeah. I think that particular "rule" might even apply to 98-up F-body flywheels, but it doesn't to third gen flywheels.

 

im running into the same conflict. ive had my flywheel machined twice now. im putting in a centerforce dual friction clutch. ive had problems with shifting into first and sometimes third. i also found that the throwout bearing was installed improperly. since i took it out how it was installed when i got it, its been installed improperly since then. but im also wondering about shims for the flywheel. anyone had these problems w/ hard to shift into gears or even grinding when shifting into reverse? mine always grinds when i shift into reverse unless i go to 5th gear first.

 

wow i just posted a lot of questions in that. sorry everyone

 

Reverse is not synchronized, so you should always shift into a forward gear before shifting into reverse.

If first and third, you may just need your trans. worked on. However, you should bleed the hydraulics and then see.

 

Shall I post my famous throwout bearing pic?

Do you know the one I'm talking about?

If not, I'll post it .... again.

Flywheels have a bevel cut around the outside of the clutch surface. If the bevel is still there, then the flywheel is within specs; if it's gone, it's beyond re-use as far as the factory is concerned.

There is no "rule of thumb" based on how many times the flywheel has been re-surfaced. Look at the bevel. It was put there as a telltale for that measurement.

That said, the hydraulics have AT LEAST twice that much automatic adjustment built into them. It's all but impossible for the hydraulics to have inadequate travel, if everything is assembled correctly and all the parts (pilot bearing) are good.