Severe engine vibration

AnotherRed86GT

New Member
Apr 25, 2006
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I had a friend change the clutch on my 95 gt. He had a problem removing the pilot bearing, so he chiseled it out while I was running around to different parts stores trying to find a puller (guess he couldn't wait). After he put everything back together, the clutch worked fine, but there was a severe engine vibration which got worse as I revved the engine, clutch in or out. I took it to a reputable transmission shop and they tore it all back down again, and didn't find anything wrong with the new flywheel or clutch. They did notice that the pilot bearing was installed crooked, so they removed it. After they had it out, they noticed good sized grooves in the crankshaft where my friend had chiseled the old pilot bearing out. Bottom line is, they got everything back together, and I'm still stuck with a vibration. The transmission shop thinks that when my friend hit the crankshaft, he either damaged the crank or messed up the thrust bearing.

So my question is, could the transmission shop be right? Could it be the thrust bearing causing all of this vibration, and could my friend have actually messed up the thrust bearing by hammering on the crank?

FYI, the harmonic damper is fine.

I really appreciate any information any of you might have... I've spent a lot of money already now, double of what I should have spent, and I'm just looking for an answer at this point prior to spending more. I've learned a valuable lesson about letting the wrong people work on my car to save a dime though...
 
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Here's probably the problem. When you (your friend) replaced the flywheel he probably installed the dowel pins in the wrong holes in the flywheel. Remove flywheel and compare dowel pin location with the old flywheel. If you don't have the old flywheel to the trans shop and have them check it out.

Word to the wise - always keep eyes on friends working on your car. I'm sure he meant well but his impatience is causing you hell.

Also, in the future, you can remove a pilot bearing by packing the hole with grease and use a solid device (i.e. pipe etc.) that barely fits in the pilot hole tap with a hammer and repack hole as necessary or buy the puller. The pressure will force the pilot bearing out. This is the method I use with excellent results.

Keep the post updated with the results. This helps future stangers resolve similar problems

Peace
 
Before you go any further, take a look at your balancer. It could be purely coincidental that the vibration happened after the trans install, but could be completely unrelated. If you see any of the rubber sticking out between the center and the outer ring, or the balancer has any wobble to it (the outer ring, not the counterweight), then it's due for a replacement. If not, I believe the transmission shop could very well be correct about it being the thrust bearing or have something to do with the grooves from chiseling the bearing out.
 
Methodical: The transmission shop that I brought it to afterward to check things out did check the location of the dowel pins... that's what they suspected as well. It wasn't that though. Also, he said the pilot bearing was "very stuck" and that removing by the grease method wouldn't work, that's why I was out looking for a puller while he was destroying my car (heh).

Stanggt1995: The balancer was changed at around 100k when I changed the distributor, it was throwing my timing off. I did just run out and check it again to make sure nothing was wrong with the new one (this is 20k miles later) and it looks and feels fine.

DDstang94: The transmission shop checked the clutch and said everything is fine with it.

FYI, I didn't mention this before, but it's an FMS king cobra clutch and new FMS flywheel. Clutch fork and pivot ball were changed. Rear main seal was changed and pilot and throwing bearings were changed.

Can someone explain how he could have damaged the thrust bearing when he hit the crank? I've asked other people and searched around, but I haven't found much information about it.


And thanks a lot for all of the replies!
 
The thrust bearing is what limits the crank travel from front to back. Hammering on the rear of the crank could have increased the crankshaft endplay. The thrust bearing should have .005-.009" of clearance. More than that and you're running the risk of breaking things like your timing chain, damaging connecting rod bearings or journals, or bending/breaking the connecting rods themselves because of the crank being out of alignment and forcing them pivot at a different angle than they were designed to.
 
It's definitely not the driveshaft.

My transmission shop tried a new stock clutch kit and flywheel and it's still doing the same thing. We're all leaning toward the thrust bearing.

I have 133k miles on the car, I guess it's time to finally spend a little money on it and buy a new engine. =)
 
Yes, we put on a prothane poly tranny mount at the same time, why? I didn't have vibration like this when I switched to a poly mount on my 86gt.

the cross member on the 86 has bushings where it attaches to the body right? the sn95 does not. change to a rubber mount. im pretty sure it will solve your problem. same thing happened to me. i installed a energy suspension mount when swapping my clutch.
 
I'm going to try this when I get home tonight. My stock mount was in great shape, couldn't hurt to take ten minutes to throw it back on!

Thanks for the suggestion, and yeah, you're right about the bushings in the 86, I remember changing those too. It would make sense that these would vibrate a lot more due to the solid crossmember to body mounting.
 
:nice: Right on man, I just finished putting the stock tranny mount back in. Vibration is 100% gone. I can't believe what an idiot I am. I also can't believe the transmission shop didn't notice this.