C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

[Gary B.]

I’m planning on getting a LUK clutch system for my ‘66 SB and I read a posting by Joe Lucia in the archives about the correct dimensions for the crank pilot bearing.

“The proper bushing should have an ID of 0.594". I would advise anyone that uses one of these bushings to check this spec before installation to make sure that the bushing is right. The OD of the correct bushing is 1.094".”

John Hinckley reported the exact same OD.

In searching for pilot bearings, I think I found the correct part numbers and dimensions for bronze pilot bearings from Dorman and National:

Dorman # 14650
ID: 0.593”
OD: 1.093”

National # PB656HD
OD: 1.096”
ID: 0.592”

I’m not keen on the 1.096” OD of the National part, nor on the 0.593” ID of the Dorman part. Is there a GM version that is more likely to match the 1.094” and 0.594” dimensions that Joe and John Hinckley reported?

Gary

[Larry M.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Gary:

As long as the pilot goes on the trans input shaft, the pilot ID should be fine. They can/will wear in. Just make sure to install with a dummy input shaft of the correct dimensions or a cut-off trans input shaft (best) so that ID does not get depressed when installing. Put bushing in freezer overnight to shrink OD a bit and make install easier/less potential for damage of bushing ID. Mic input shaft to check what actual OD of your nosepiece is.

OD can be reduced by using some sandpaper and a drill press. Use drill press to rotate pilot and dress the outside with the sandpaper and a piece of glass or flat board to keep the sandpaper straight/parallel to the pilot OD surface.

Having said that, AUTOGEAR will make you a custom pilot in the proper Oillite bronze material if you want. Go to their website. They stock regular pilots in Oillite as well, but can and will custom machine for a customer. I know of a few folks that have done that. Their spec pilot for our cars is 0.593 x 1.093 inches x 0.720 inches length. Part # 0-127-006

Larry

PS: I do not recommend trying to enlarge the ID of the pilot bushing, since it will likely close up the Oillite pores in the precess.

[Frank C.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Gary,
I will be replacing the clutch on my 66 L79 as part of a major mechanical rebuild. I have included the picture of my replacement Luk clutch kit #C4-021 and pilot bearing kit. I was curious and opened the pilot bearing package and provide the following measurements:

Outside Dimension: 1.0965
Inside Dimension: .5925

So a couple of observations and I am here to learn. Maybe someone who has installed many more than me can offer an expert opinion. We are working on mass produced Chevrolet's using mass produced parts. This means the shaft on the transmission can vary, and the ID of the crankshaft can vary. For the crankshafts, this is especially true if it is replaced. I looked on Summit Racing website and the Dorman part # 14650 you referenced according to them comes in 1.094/.0594 OD/ID. Here is my opinion. This Summit part and the part I am showing is made from bronze and size can vary. Even if you order the Summit claiming 1.094/.0594 OD/ID, it will probably mic out to higher or lower due to acceptable machining tolerances.

What I am going to do is match my pilot bushing to my transmission shaft and crankshaft. The bearing I have is larger OD and smaller ID so they can be turned to match to my crank and transmission shaft.

One more thing. Summit and I am sure others offer roller bearings for the pilot bushing. These are ground to a very high tolerance, and when they are quoted as 1.094/.594 OD/ID these will be spot on. https://www.summitracing.com/parts/m...make/chevrolet

Does anyone reading this have experience with the roller type bearing for the clutch? Thanks, Frank

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[John S.]

[Gary B.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

[Frank C.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Gary,

The needle bearing appeals to me because of the precision. When I am out in the shop next, I will mic the crank and trans shaft. We will learn together. Keep us posted on your progress. Frank

[Larry M.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Gary,

The needle bearing appeals to me because of the precision. When I am out in the shop next, I will mic the crank and trans shaft. We will learn together. Keep us posted on your progress. Frank

A LOT of downside to the needle bearing vs the Oillite bronze bushing.

But if you disregard my advice on this, then be damn sure you dial in the bell housing to crank centerline. I have helped friends install the needle bearings, but we ALSO dialed in the bell housing. One without the other is a recipe for problems.

Larry

[Gary B.]

[Gary B.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Larry,

Advice noted.

Gary

[Frank C.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Gary, I just checked the bearing I have with a strong magnet. No attraction I can detect.
Frank

[Gary B.]

[Patrick B.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

Gary,

The needle bearing appeals to me because of the precision. When I am out in the shop next, I will mic the crank and trans shaft. We will learn together. Keep us posted on your progress. Frank

[Joe L.]

Re: C2 Clutch Pilot Bushing/Bearing; who sells one with the recommended OD and ID?

70’s Mustangs used needle bearings. When one failed on a friend’s Mustang, the trans input shaft became stuck to the crank, negating the clutch. We machined down a Chevy oilite bearing to fix the Ford.

Patrick-----


Most C4 Corvettes (except LT5) originally used a needle bearing type pilot bushing. These can also be used on all earlier Corvettes. However, when using this type bearing PERFECT alignment between trans input shaft and engine crankshaft is absolutely MANDATORY. Otherwise, what you describe with the Mustang is in the offing. If one is not certain of this alignment, one should not use or convert to the needle bearing type