Vibration, failed pilot bearing, discolored flywheel
#1
Vibration, failed pilot bearing, discolored flywheel
Gents,
My HPDE car developed a vibration at VIR last weekend. I cut my track time short, but had to drive her home. I could not find anything suspect on the engine side, so I pulled the transmission. I found the brand new Koyo pilot bearing had leaked its grease. It spun freely but felt "empty" inside and loose, if that makes any sense. The flywheel has three places where the surface is discolored, I assume from hot grease flowing down after the car gets parked, then being flung around next time she's run. The picture is the worst of those.
I have a very nice precision square. I checked the flywheel and there are no noticeable high spots. The friction plate has some discoloration. However, I did not notice any shifting problems on track or on the way home. The clutch has about 70 track days on it plus commuting, purchased in August '15.
Seems like replacing the clutch is the right thing to do. Should I replace the flywheel? It's been resurfaced once already.
Thanks,
Worst of three flywheel discolorations
My HPDE car developed a vibration at VIR last weekend. I cut my track time short, but had to drive her home. I could not find anything suspect on the engine side, so I pulled the transmission. I found the brand new Koyo pilot bearing had leaked its grease. It spun freely but felt "empty" inside and loose, if that makes any sense. The flywheel has three places where the surface is discolored, I assume from hot grease flowing down after the car gets parked, then being flung around next time she's run. The picture is the worst of those.
I have a very nice precision square. I checked the flywheel and there are no noticeable high spots. The friction plate has some discoloration. However, I did not notice any shifting problems on track or on the way home. The clutch has about 70 track days on it plus commuting, purchased in August '15.
Seems like replacing the clutch is the right thing to do. Should I replace the flywheel? It's been resurfaced once already.
Thanks,
Worst of three flywheel discolorations
#10
I've had the flywheel resurfaced and sourced a Nachi bearing with the plastic seals rather than the metal shields. All I can think to do is bolt everything back up and see if the vibration is gone. At speed, the vibration felt like an out of balance tire, but I could feel it parked at idle.
Usually, she gets put into the garage after the last event of the season at the beginning of November, and I don't touch her till after the holidays. Now, I want to find out if I have a bigger problem before moving ahead with rebuilding the other motor. I've run the engine without the supercharger belt, and without the alternator belt (briefly). Then I stripped down the front of the motor so I could run her without the timing covers. I could not find anything that would point to the source of the vibration, although I did find a couple of exhaust valve clearances a little too large. Then I pulled the gearbox. I didn't find anything improperly torqued on either the engine or trans.
I plan to spin the output shaft of the transmission and see if there is any input shaft wobble, but after that I'm completely out of ideas. The motor was very strong, even with the vibration.
Any ideas would be greatly appreciated,
Usually, she gets put into the garage after the last event of the season at the beginning of November, and I don't touch her till after the holidays. Now, I want to find out if I have a bigger problem before moving ahead with rebuilding the other motor. I've run the engine without the supercharger belt, and without the alternator belt (briefly). Then I stripped down the front of the motor so I could run her without the timing covers. I could not find anything that would point to the source of the vibration, although I did find a couple of exhaust valve clearances a little too large. Then I pulled the gearbox. I didn't find anything improperly torqued on either the engine or trans.
I plan to spin the output shaft of the transmission and see if there is any input shaft wobble, but after that I'm completely out of ideas. The motor was very strong, even with the vibration.
Any ideas would be greatly appreciated,
#12
Cpt. Slow
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Like I said, as long as the pilot bearing still spun freely, it hadn’t failed, just slung out all its grease. Even a locked up pilot bearing won’t cause a vibration, only a squeal or a chirp.
#18
It happened to me just changing out engine mounts- car had more vibrations right off the bat. Though I didn't loosen the PPF-trans bolts when changing to the mounts, it somehow became mis-aligned. The fix was loosening the PPF trans bolts, putting a jack under the trans and lifting it slightly, then tightening the bolts with the jack still holding it up a bit. I can't remember off the top of my head, but there are measurements you can take of a couple of areas to check for/to adjust correct PPF alignment.