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Clutch Chatter on newer clutch


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I put in a new excedy clutch in my 96 outback along with a new updated throwout bearing and metal snout sleeve (for smoother clutch action and to prevent clutch chatter). It worked perfectly with no noticeable chatter and it was the smoothest clutch I had ever had. That week my engine decided to throw a bearing. I rebuilt the engine and threw it back in my car. Now I get chatter and the whole car vibrates when I engine brake into 2nd or first gear. I made sure that I cleaned the flywheel and pressure plate thoroughly before I put it back in. I do think I made a mistake though. It was late and I was very tired when I put the clutch in. When I looked at the book for specs it said to tighten the pressure plate down in a circle pattern. I thought that was odd because I've always crisscross tightened everything down on all previous clutches but I decided to do the circular pattern. I looked at the book again today and it said to finger tighten everything in a circular pattern then crisscross everything to torque so you don't distort the pressure plate. So I figure I must have distorted it. Did I completely ruin it or can I just re-tighten everything the proper way?

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Not sure about pressure plate distortion and the effect circular tighening could/would  have

 

Could be engine / gearboxs mounts.  

 

Was the flywheel face scored?   Did you take flywheel off and get it refaced  / surface machined?  

Edited by subnz
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You rebuilt the engine and now you have higher compression - more breaking effect.  I doubt it's the clutch if everything else about the clutch is OK.  If the pressure plate was tight up against the flywheel and the centering tool slid in an out with ease it should be fine.

 

I'd look at your drive shaft u-joints and then the rest of the drive line.

 

Using the engine as a brake is not the best thing for it anyway, IMHO

That's what brakes are for.

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You rebuilt the engine and now you have higher compression - more breaking effect.

I seriously doubt that is what's causing this problem. I put a 30k mile engine in my car with my old clutch and it never caused and issue.

 

I would suggest pulling the engine or trans again and redoing your tourque sequence on the clutch disc and inspect everything. If nothing else for the peace of mind.

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Using the engine as a brake is not the best thing for it anyway, IMHO

That's what brakes are for.

What? Slowing down with your engine doesn't do any harm to anything unless your seriously over revving it. The best is a mix of engine braking and use of your brakes.
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Hmm thats a good thought about the new engine but I'm pretty sure it's not that. The engine I took out had 180+ compression on all cylinders so just about good as new. I'm just wondering if re-torquing will actually do anything or not.  If the clutch disc is was creates most of the torque when you initially torque it down then if the clutch has already been engaged it's essentially like the the disc has been freed and so how would retorquing it actually fix things? Does that make sense? I will try but man thats gonna suck if it doesn't work and I have to take it out again.

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Hmm thats a good thought about the new engine but I'm pretty sure it's not that. The engine I took out had 180+ compression on all cylinders so just about good as new. I'm just wondering if re-torquing will actually do anything or not. If the clutch disc is was creates most of the torque when you initially torque it down then if the clutch has already been engaged it's essentially like the the disc has been freed and so how would retorquing it actually fix things? Does that make sense? I will try but man thats gonna suck if it doesn't work and I have to take it out again.

I did say to inspect everything, its possible not following the torque sequence caused some bolts to be loser than others.

If it worked when you pulled it out, something you did when installing is causing your problem.

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I machined it when I first put it in. I called the subaru performance parts shop I bought it from and they basically told me that I'm screwed and the reason its chattering is because I resurfaced my flywheel and that Subaru only uses new flywheels because of this reason. Something about the tolerance being off (even though I told them it was within spec). I call BS on that. I called a Subaru Service Department in Colorado Springs and they said they always resurface flywheels.

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You only had the flywheel machined once, correct? It was not re-machined before the second install?

When you took the clutch off to do the engine swap, did you mark the alignment of the pressure plate and flywheel relative to each other? 

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I put a new clutch in when I put a engine in but it had a knock so I rebuilt one and put it in there. So the clutch has only a few hundred on it. The allignment pins only allow it to install in one position. I'm wandering if I hit one of the pressure plate splines when I was installing it. Gonna take it out again tomorrow and check it out. Oh and I ended up calling excedy and they called BS on what the dealer said.

Edited by gravitate
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So I took it out today and I notices one of the Pressure plate fingers had a noticeable wear from the throw out bearing. So that might explain the clutch chatter. I checked the PP and the Flywheel for straightness and they are both fine. Neither of those had any noticeable wear or hot spots, look new. But the disc does have some odd wear. I noticed this same kind of wear when I took this out the first time (before the clutch chatter) but I thought it might be normal but now. What do you think? Dull spots are the wear and shiny is the new.

post-26324-0-94341400-1456987160_thumb.jpg

post-26324-0-04718100-1456987340_thumb.jpg

Edited by gravitate
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So the pressure plate was only worn on one finger? Did you check to see if that finger was sticking up higher than the others before removing the pressure plate?

 

Does the release bearing move easily on the release fork?

I've seen some have rough spots or edges that bind with the release fork and cause it to engage the pressure plate unevenly.

 

The shiny spots are where the pressure plate is engaging the clutch disc first, and its overheating and glazing the disc in those places. That's due to uneven engagement of the pressure plate to the clutch disc and flywheel.

Usually you can also see hot spots or glazing on the flywheel and pressure plate. That's where the plate is making contact first.

 

Unfortunately, you're going to need a whole new clutch set.

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Yeah thats what I thought about the wear but I ended up calling Exedy back and emailed them the pictures and they said if I only have 500 miles on it that it is just normal wear for the break in period and that it is normally a little shiny when they are new and the rougher looking spots are wear. He noticed that it looked like there was grease stains on the disc coming from the center. I inspected it again and sure enough there was very faint amount of residue on there. Seems that I over greased the input shaft or something and the centrifugal force shot it out onto my disc.. I cleaned it up, barely greesed the shaft and slapped it back on. Works great now.

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  • 1 year later...

What? Slowing down with your engine doesn't do any harm to anything unless your seriously over revving it. The best is a mix of engine braking and use of your brakes.

Have you ever noticed that it is much easier to replace brake parts than it is to replace engine parts. Piston miles add up without any help from "engine breaking" but if that is what cocks your hammer then by all means do it.

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