So I have a 4.9 V8 fiero daily driver..... and like many V8 fiero drivers I had issues with the clutch slipping.

I don't make a whole lot of money.... so I have to stay away from expensive custom parts and I do my own mechanic work.

So I had heard that the S-10 clutch has a larger disc and pressure plate... yet maintains the same bolt pattern on the flywheel and same input shaft spline count.

I took a trip to Autozone and a new clutch was only $79.99, lifetime waranty! .... Compared it to a Fiero V6 clutch and it looked a lot bigger indeed. One thing than concerned me was that the forks came up quite a bit higher than the Fiero pressure plate.

Well I decided to buy it and install it in my Fiero..... since there were a few sources that recommended this clutch for heavy duty use in a Fiero.

Well, after getting it all in after a long hard day.... I took it for a test drive..... The DAMN thing was slipping more that the original !!!!

I drove it for a few days thinking it would just need to be broken in, but it just kept slipping even with the slightest throttle. As soon as I depressed the clutch pedal not even 1/4 the way in it would be FULLY released from the engine.

.... and then it dawned on me. The clutch was so big that the throwout bearing was pressing on the forks constantly.

I was quite dissappointed.... I sure the heck didn't feel like going and putting in the old clutch back in!

So I thought to myself....What if I add some washers between the engine and trans..... would that be enough to allow the clutch to work right? That would be rigging it for sure!!

Well I decided to add one 1/16 inch thick washer for each of the five bellhousing bolts.......... and it worked! This clutch would not slip for anything!!! I could finally do the massive burnouts that I thought a 4.9 could never do! I could launch so hard that it almost feels like the front wheels would come off the ground!

.... Well needless to say it was still not right to have washers between the the engine and trans. And a few months later I took off the flywheel and had it turned down 1/16 of an inch and did away with the washers.

I bought the Heavy Duty Clutch from the Fiero Store when I did my 4.9 build 4 years ago. I have had no problems with it in all that time, I use the car as my daily driver in the summer and have run it at the drags and Auto Cross. The unit I used is Part # 54007 from the Fiero Store.

Joe Sokol

------------------
85 SE Daily driver with a 3.4 DOHC build underway
88 Formula/GT 4.9 Allante Intake (My Baby)

quote Originally posted by v8fiero400: So I thought to myself....What if I add some washers between the engine and trans..... would that be enough to allow the clutch to work right? That would be rigging it for sure!! Well I decided to add one 1/16 inch thick washer for each of the five bellhousing bolts.......... and it worked! This clutch would not slip for anything!!! I could finally do the massive burnouts that I thought a 4.9 could never do! I could launch so hard that it almost feels like the front wheels would come off the ground!

This is an idea I though about doing on a 3800 swap instead of having the flywheel cut down. Not so much use washers but use a solid spacer inbetween the trans/motor to make a stock 3800 flywheel work. I really dont see a problem doing it this way and this lets me know it will work.

quote Originally posted by MstangsBware: This is an idea I though about doing on a 3800 swap instead of having the flywheel cut down. Not so much use washers but use a solid spacer inbetween the trans/motor to make a stock 3800 flywheel work. I really dont see a problem doing it this way and this lets me know it will work.

The easiest and safest thing to do is go to a clutch builder and have them integrate the clutch parts properly so that it all goes back together in stock form. I was made aware of this option back in 96 by a Clutch rebuilder who offered to do just that and ultimately produce a finished product stronger than the stock S10 unit since spring pressure could also be increased. The clamping pressure is about the same, however the larger diameter provides more holding capacity in the form of twisting leverage with the disc lining a little further away from center.

You could also have had the outer perimeter of the flywheel machined down some instead of the entire flywheel to allow for a little more clamping pressure with the pressure plate mount pads being a little lower than the clutch disc friction surface on the flywheel. That method would insure higher than usual clamping pressure as the clutch disc wears and gets thinner.

As for my comment about the spring pressure in the S10 pressure plate being about the same, that came from an inquiry with SPEC years ago when I was looking to increase holding capacity by using S10 parts.

Here is my stepped flywheel after the engine was removed for my swap. I discovered something important about dual friction semi metalic discs, they are hard on flywheels, you can't see it in this picture but the friction surface was worn down to about the same amount the perimeter of the flywheel was machined.

[This message has been edited by Joseph Upson (edited 01-21-2008).]

As I recall, the clamping force for the S10 pressure plate is a good bit lower. It MIGHT be 1350 for the fiero and 1050 for the S10. Whatever it was, it pretty much negated the size gains. Though I considered the advantage of more leverage from the outsize diameter being larger, the % size increase was less than the % loss of clamping force. I found the same numbers in the clutch book at the parts store for stock spec clutches and from Spec for an aftermarket.

I used an adapter plate for my ecotec project, one solid piece between the trans and engine. No probs with it cept a shield is needed for the bottom

quote Originally posted by 86GT3.4DOHC: As I recall, the clamping force for the S10 pressure plate is a good bit lower. It MIGHT be 1350 for the fiero and 1050 for the S10. Whatever it was, it pretty much negated the size gains. Though I considered the advantage of more leverage from the outsize diameter being larger, the % size increase was less than the % loss of clamping force. I found the same numbers in the clutch book at the parts store for stock spec clutches and from Spec for an aftermarket.

Glad to see those numbers, now I understand why the clutch builder advised against increasing the spring pressure in the 6 spd pressure plate which he measured at ~2000 lbs suggesting I shouldn't have any problems with slipping.

In this case having the builder rework the Fiero pressure plate combination to use the cover and spring along with the S10 friction plate should yield the added advantage.

quote Originally posted by 86GT3.4DOHC: As I recall, the clamping force for the S10 pressure plate is a good bit lower. It MIGHT be 1350 for the fiero and 1050 for the S10. Whatever it was, it pretty much negated the size gains. Though I considered the advantage of more leverage from the outsize diameter being larger, the % size increase was less than the % loss of clamping force. I found the same numbers in the clutch book at the parts store for stock spec clutches and from Spec for an aftermarket.

I fing that hard to believe. The S-10 clutch holds on A LOT tighter than the V6 clutch before it. I base this on actual hard driving.

yes but your also comparing new to old...big difference right????