Drivetrain squeak

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Series8217
1988 Fiero Track Car
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Drivetrain squeak

Post by Series8217 »

While rolling, with the engine RPM higher than input shaft RPM, quickly engaging the clutch causes a VERY loud squeak sound. It's almost like a belt squeal, but more metallic.

I don't think I have a broken engine mount; I can't move the motor with my hands no matter how hard I try to shove it around.

Accessory belt looks ok.

Any ideas?
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Emc209i
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Re: Drivetrain squeak

Post by Emc209i »

Rivet on the clutch making contact with the flywheel? How old's your clutch?
The Dark Side of Will
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Re: Drivetrain squeak

Post by The Dark Side of Will »

I've read that you know if you pulled off a great 1-2 shift when driving a Ford GT if the supercharger belt chirps.

Does the squeak get louder as the RPM difference between engine and input shaft increases?

Is there a place where the accessory belt could be rubbing something in the engine bay?

Do you have all the covers on your timing belt?

Sprung hub clutch?
Jinxmutt
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Re: Drivetrain squeak

Post by Jinxmutt »

I know you checked this, and probably not the case, but my engine used to get a squeak when the nuts on the engine mount loosened up in the cradle. I got a socked up in there and the squeek stopped.

My broken clutch also squeaked before it failed.
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Series8217
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Re: Drivetrain squeak

Post by Series8217 »

Sprung hub clutch, yeah. About ~15k on it I think? Maybe more. 20k?

Engine mounts are tight.

Nowhere the accessory belt could be rubbing. Timing belt covers are all in place, though it's possible I'm missing some screws. They covers are very weathered so I'll check the belt when I put my new ones on this week.

I've been thinking it's the clutch, so I ordered a new pressure plate from Rockauto and am going to pick out a new disk this week. It won't be another Spec.

Jinx, what was the failure mode on your broken clutch when it finally gave out?
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Re: Drivetrain squeak

Post by Jinxmutt »

One of the springs popped out.

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Series8217
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Re: Drivetrain squeak

Post by Series8217 »

Hmm.. That's sort of what I figured was going to happen with mine.

What are you running now?
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Series8217
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Re: Drivetrain squeak

Post by Series8217 »

I replaced the clutch. and found my flywheel bolts slightly loose... again. Last time I replaced the bolts and got a Fidanza aluminum flywheel, and the crank threads are fine, so it's not a parts problem.

Apparently this is a known issue with the Fidanza flywheel.. but I don't think its because of the aluminum flowing; I think it's because I didn't actually get as much torque on the bolts as I thought I did when I torqued them down. The bolts go into counterbores that make it impossible to fit a normal socket over the heads. I think other people did the same as me; they got them as tight as they could and when the wrench slipped off or rounded the bolts they gave up. This time I turned a socket down to fit, and also torqued them with red loctite. Should be good to go.

The spec clutch looked perfectly fine. Couldn't see any problems with it.

I'm using a Sachs pressure plate now with a Clutchnet 6-puck sprung hub. Holy fuck this is the strongest clutch I have ever seen. It looks entirely unbreakable. I'll post some pics when I get a chance. They have further strengthened the design since the last clutches I saw from them. On the downside, it's noticeably heavier than a stock clutch, and I don't think my synchros are very happy about that... My transmission does not like going into 2nd gear now after a 7k RPM run through 1st, and it used to be fine.

The Sachs plate requires noticeably less pedal force to disengage. When I first got everything back together, I think the pressure plate fingers were hitting the clutch disc at maximum travel, so I couldn't get into gear unless the pedal was only 3/4 of the way down. After 20 miles of breakin that problem is completely gone. I think once the clutch seated to the flywheel surface, the pressure plate travel moved further out so it was no longer an issue.

I replaced my Fidanza friction surface; the kit is available from Summit for like $65. It comes with the steel friction plate and new fasteners. The friction plate is just a piece of laser cut steel with the holes countersunk on one side. They don't even surface the plate after they laser cut it. Ehhh. It works though. I had a shit-ton of chatter for the first 100 miles but it has smoothed out a lot now, especially after I got pissed at it and did a short clutch burnout.

Oh yeah, the driveline squeak seems to be gone.
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