puzzled about clutches, '91 318is

[RadioRon]

I'm shopping for a clutch and noticed that the part number depends on whether the car has ac in it or not. Why the difference? Did BMW equip non-ac cars with a different flywheel setup than the dual-mass one in my ac equipped car? I'm asking because I'm interested in a lighter setup that would still be "ST" legal in autocross (i.e. not an aftermarket or swap setup).

My car is 1991 318is M42 with ac.

thanks

Ron

[Blackice]

The difference is the huge. will find the post here give me a sec

PS, I have a clutch that will fit your car, new in the box.

[Blackice]

Here is the the thread, there are some photos to show the differance between the 2 set ups..... The non ac fly wheel is a lot lighter. But would require the clutch and the fly wheel to be replaced at the same time.

http://forums.bimmerclassics.com/3-s...n-ac-318s.html

[Blackice]

I have a clutch kit for sale for the 318 A/C check it out here

http://forums.bimmerclassics.com/cla...lutch-kit.html

[RadioRon]

Thanks for the links. At the risk of seeming a bit thick, I admit I'm still a bit puzzled. Is the combined weight and rotational inertia of the dual mass clutch+flywheel setup different than the non-dualmass setup? I mean is there a benefit to converting to the stock single mass unit? Will it let me accelerate better?

One reason for confusion is inconsistent information at parts suppliers. For example, when I look at Pelican parts, I see they list two flywheels for 90-91 M42 318, one is dual mass and one is not. But when I go to look at pressure plates and clutch disks, the only units for same 318 are for dual mass. No disks or pressure plates offered for single mass. Why? The shipping weight for the single mass flywheel sure is a lot lower than for the dual mass one. But the pressure plate in your photo (the thicker one) looks heavier.

[Mr. Red]

Hey guys!!

I just picked up a 1991 318is and really the only thing that bugs me is how late the clutch engages..my foot is almost off the clutch by the time the engine engages. Does this mean my clutch needs replacing? There's no slippage yet, but would a new clutch kit fix this??

[Blackice]

Originally Posted by Mr. Red Hey guys!! I just picked up a 1991 318is and really the only thing that bugs me is how late the clutch engages..my foot is almost off the clutch by the time the engine engages. Does this mean my clutch needs replacing? There's no slippage yet, but would a new clutch kit fix this??

The clutch has a self adjusting feature, so the clutch engagement very late or high is a sign that the clutch is worn. I found that the clutch started to shutter a lot at the end of its life. You might get the summer or more out of that clutch if you are kind to it. But the writing is on the wall so to speak.

[RadioRon]

Mine is pretty high too, almost at the end of the peddle travel. But it isn't stuttering yet. It takes quite a while for it to engage at high revs, but is still working adequately with easy driving on the street.

[RadioRon]

I have a follow-up question. Can anyone recommend a machine shop in the Vancouver area who knows how to shave weight from a flywheel?