Shim resurfaced flywheel?
 

I just had a used stock t-5 flywheel resurfaced. Since I bought it used, I asked the machine shop guy how much material is worn off from stock. He said that it is pretty well used.

Then he made a wierd comment. He asked if I am using a hydraulic clutch. I said yes. He said that I may have to shim the flywheel...but he wasn't sure if GM flywheels needed to be shimmed or if he was thinking about Ford or Mopar.

Why would I need to shim the flywheel? My understanding is that a flywheel will wear a bit, but that the hydraulic clutch should compensate for both clutch and flywheel wear. Is he referring to engagement issues?

TIA...

When I got my T56 flywheel resurfaced....I asked about shims since I had heard I would need shims.....the guy there said that I wouldnt need to use them since I have a hydraulic clutch........I went ahead and installed it without a shim...but Im wondering if I need them as well.

I have never really dealt with used clutch parts. I thought it was a wierd comment from him.

What kind of problems are you having that would make you think you should use shims?

Does anyone else have any experience with this? RB?

Thanks,

the way i understand it....the reason for using shims is to make up for the material that is taken off when the flywheel is resurfaced. The shim goes between the crank and the flywheel itself. Supposedly when you take material off.....the pressure plate becomes slighlty further than a factory thickness flywheel. Whether or not this distance will cause problems is the question. I would think it would be just like the brake system....once the brakes thin out...its no big deal cause the entire system adjusts itself. But i could be wrong.

In these cars, the hydraulics have a considerable amount of slack they can take up. If the flywheel has been turned so much that it;s outside that range, then it's well beyond the point of discarding and replacing. In other words, by the time you thin it down to where it affects the hydraulics, you have much bigger issues than the hydraulics.

There's a beveled edge around the outside of the clutch surface of the flywheel. I wouldn't worry about it as long as that bevel is still there. If the bevel is gone, then the flywheel is too thin to be safe (if of course you like having feet), and should be replaced. The hydraulics are designed to work properly at least to that point, and usually much farther, before they run out of adjustment range.

I've pulled apart a 91 Z28 stripper LB9 / T5 before and it had a flywheel shim in betwen the crank & the wheel. Never seen one otherwise. They aren't necessary in the third gen application because like R said, the range of motion in the third gen fork, t.o. brg. and related parts is more than adequate for the difference due to a surfaced flywheel.

b.t.w., it was made of chinesium.

i just had my flywheel resurfaced and got a new clutch at my local shop and the guy put a shim in

im pretty sure you will be fine wihtout one though as others have said

Sweet...

I will be picking up the flywheel tomorrow and will check it out.

Thanks for all the help guys!

Followup:

I picked up the flywheel and there is a LOT of bevel left. It appears to have been a stock, unmachined flywheel that had seen around 80K of use (so said the previous owner). It cleaned up really well and should be fine to use...

Thanks to all who responded (especially RB)...

as mentioned before, some flywheels need shims, and it's good insurance to put a shim between the flywheel and clutch. Yes the hydraulic clutch does have a wide range of motion, but unless a mechanical clutch that you can adjust the slack out of, if your slave cylinder doesn't have enough throw on it, it might cause some problems. most of the time you can get away without using a shim, but i have heard of flywheels that do need it, cause some strange problems.