Clutch and Flywheel Wear Pattern

[efnfast]

Just an obervation, Jim, is it the hole that is out of center, or is the bevel cut off center making the hole look out of line. Maybe it's just the camera angle, but when I hold my precision pen held up to the screen it makes it look like it may be an optical dilution.

[QB93Z]

I have done a more detailed inspection of the pilot bushing.

The picture I posted was the end of the bushing facing the block. On the end of the bushing facing the transmission, the misalignment is less noticable.

I measured the wall thickness of the bushing with a caliber:

From the transmission end: Thin side is 6.26mm, wide side is 6.35mm

I tried measuring the thicknesses on the engine end of the bushing (the end in the picture), but there is a raised rim/edge on that end which made the mesaurements suspect.

The pilot bushing was tight in the crankshaft. We removed it using a blind hole bearing puller. The bit end of the puller made the axial marks on the inner surface of the bushing.

Visul inspection of the crank shaft while we had it apart showed no abnormalities.

So my conclusion is that the hole in the bushing is slightly off center and angled slightly to one side.

I appreciate all of your comments. It is a good discussion.

Jim

[rhipsher]

Ah! Hello. Machinist speaking here. I know that my 23 years of machining experience doesn't hold much weight. But that hole was manufactured off center. Aint no optical illusion or chamfer. Even the I.D grooves are symmetrically off with the whole. These are my old pilot bushings from two of my trans pulls and they are clearly on center front and back.

[GOLDCYLON]

Im not machinst but wow Jim that is WAY off center just look at the offset surface area on one side vs the other. I think the bearing grease failing and going into the surface area and scoring are also strong on what happend list.

[rhipsher]

That pilot bushing hole being that far off center is going to cause your whole drive train to sit cockeyed. Transmission will be off to one side. Uneven contact between plates. That bushings is your entire problem. Must have been slipping like a mofo.

[mike100]

According to Bill Boudreau, you do NOT add any grease to those bronze bushings. The grooves and the impregnated material provide lubrication.

If you do lube it, once the grease dries out, the bushing will spin in the back of the crank and generally get worn out much faster. Mine was spinning and the car only had 28k miles on it...the clutch even less because it had been replaced once already.

I'm sure that clutch will feel 100x better with all new parts and a propely installed pilot bushing. I used the same disc and flywheel and I could tell a big difference upon reinstall of just the bushing change.

[scottfab]

Originally Posted by gbrtng

Amazing - It looks like the bushing is a replacement and was damaged by the input shaft clanking into it when the ZF was being reinstalled. Equally hard to believe that the bushing didn't knock out the crankshaft plug.
How did you remove the bushing without damaging it?

Removing a pilot bearing without so much as a scratch is not hard.
I've done it twice.