MANUAL TRANSMISSION — Clutch Pilot Bushing Information

[bbodie52]

Howling Pilot Bushings How and Why!
by: Al Lacki

The Fifth Wheel - LVCC - Jan 2016 (Corvair Pilot Bushing Article).pdf

The Fifth Wheel - LVCC - Jan 2016 (Corvair Pilot Bushing Article)

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The Corvair transmission input shaft, which is probably not too busy when you have the engine separated from the transaxle, can simply be pulled out of the transaxle and inserted into the crankshaft pilot bushing to use as a clutch disc alignment tool (as shown in the photo on page 3 of the above LVCC newsletter article). When finished with the clutch installation, simply return it to is regular home.

And yet Corvair pilot bushings are such small things. According to my vernier caliper, the internal diameter is a tick over 15 millimeters [0.590551 in.], the outer diameter is a tick over 23 millimeters [0.905512 in.], and the length is three quarters of an inch.

Lisle 55500 Clutch Tool
https://www.amazon.com/Lisle-55500-Clut ... P1AWER57GR

Question:What are the eight pilot bearing sizes?
Answer:bushing sizes listed on the package are as follows: .590 .612 .624 .668 .749 .786 .808 .984

Product description
Shaft and bushings provide an accurate fit for eight pilot bearing sizes and the tapered cone handles the rest.

[Allan Lacki]

For those of you having trouble seeing or reading the article referenced above by Brad, here is the URL that will take you directly there.

http://www.corvair.org/chapters/lvcc/lv ... _wheel.pdf

My troubles with screeching pilot bushings ended when I installed a genuine NOS GM pilot bushing. Theoretically, the aftermarket bushings sold by our favorite Corvair vendors are made with the same grade of Oilite as the originals, and they were certainly durable. But they screeched.

Perhaps I shouldn't blame the aftermarket bushings. Perhaps it was due to the installation technique. I always tried to tap them in gently, but when I installed the NOS GM bushing, I used a different technique. I put the bushing in a plastic bag and covered it with dry ice overnight. The bushing shrank to the point where it pressed-in with gentle pressure. (Naturally, they expand back to original size when they reach ambient temperature, so there's no danger of them slipping out of the end of the crankshaft). I haven't had trouble ever since.

[joelsplace]

Great info. Thanks Brad!
A lot of the aftermarket ones I've seen were like the article warned about. Shiny finish not speckled.