Pilot bearing vs bushing
 

I went over a friend’s house today to install his flywheel and remove and install the pilot bushing.
This is what I removed from his crank. Lucky for him it did not tear up his input shaft.
This is why I only use a bronze bushing!
Joe

http://i559.photobucket.com/albums/s...e/IMG_0251.jpg

Can't argue with that picture. I've never used a roller bearing and never will. I see no advantage to them. Only dis-advantages.

Jim

When in doubt, do as the engineers did. They knew about pilot rollers when the C-2 was designed. They also knew, the C-2 design was a little too loose to use something as precise as the needle roller!:D

Nothing wrong with the right bushing!

When hammering in a pilot bushing, what can you do to minimize the abuse to the thrust bearing surfaces? (other than freezing the bushing)

Or is there nothing to worry about -- just flail away?

"thrust bearing surfaces"
Do you mean the face of the bushing facing you when installed?
I use a bushing driver the same OD as the bushing, never drive it in with just a hammer, and drive it in until it is flush with the crank. Never had any issues. Always install the bushing with the concave center facing outward.
Joe

Joe:

I'm worrying about the rear crank main bearing, the one with the flanges (thrust?).

Seems like the flange surfaces would take the brunt of the hammering. So I was wondering if there's some trick to block the crank's flywheel mounting flange while you beat the pilot bushing into place.

Mike

I wouldn't worry about the thrust surface as long as you are not using a 5lb. lump hammer!
Back when GM did not use a bolt to hold the balancer on the accepted method of installing the balancer was to drive it on with a block of wood and a large hammer. I must have done hundreds that way and never had anyone come back with a bearing problem.
Joe

Joe, that picture speaks volumes. I only use the solid bronze bearings, never had any problems ever with those. :smash:

tko?

Sure Looks Familiar
 

When I rebuilt the L79 from my 66 Coupe in '94, I read that GM had a 'better version' of the aftermarket roller needle pilot bearing. Something like 17 or so rollers instead of the 12 the aftermarket versions came with. Hey, must be a good way to go sooooo, I picked up a few. Since '94 I've only put about 5K miles on that engine but started to notice an odd thing happening about a half dozen years ago. After putting the shifter into first I had my hand off the shifter and was slowing letting the clutch out, as you'd do in traffic or in this case, moving up the staging line at Infineon Raceway at the Wednesday Night Drags. Well, as the clutch started to engage, I heard this strange 'rattle' and felt a vibration and on occasion, the shifter would try to kick back out of first gear. All this was happening with the car barely moving. The work-around was to keep my hand on the shifter but last year when the speedo stopped working due to a slightly mis-aligned steel drive gear and the trans had to come out, the reason for the rattle and popping out of first gear showed itself. The new/unused GM roller pilot bearing is on the left and the disintegrated one on the right and debris out front is from my 66 Coupe after about 5K miles.
http://i217.photobucket.com/albums/c...e/DSCN0371.jpg
It now has a GM brass pilot bushing and no problems since.
Mike T.

:iagree:

Pretty substantial evidence to avoid roller pilot-shaft bearings. I tried one when I first reassembled my car and because I was having some transmission problems and had to remove it several times, I discovered I couldn't keep the bushing in the crankshaft - it was always loose. Finally gave up and went back to bronze before it could mess up.

Curious - Vet65te and Plaidside - did you both dial indicator check your bellhousings for radial runout as they suggest? My assumption is you probably did and it apparently makes no difference.

And how many times in the past have I said that the above photos are why I do not and will not use the roller pilot bearing???????
Below is what can occur to the pilot of the input shaft when a roller bearing fails.

http://i65.photobucket.com/albums/h2...s/100_0945.jpg

Tom Parsons

[QUOTE=Curious - Vet65te and Plaidside - did you both dial indicator check your bellhousings for radial runout as they suggest? My assumption is you probably did and it apparently makes no difference.[/QUOTE]

I took this out of my friends 69 Camaro. He had someone put an engine in his car over 15 years ago and he said they put in a new clutch at that time.
Funny thing, he had severe clutch chatter and a noise when the car was in neutral at idle that sounded like a bearing. It went away when he depressed the clutch.
From his description I thought it was a front transmission bearing. So while the trans was out he brought to me and when I disassembled it and I could not find the cause. I rebuilt it anyway just to be safe.
So I wonder if this bad pilot bearing could be the cause.
I will help him next weekend to install the transmission and see if his problems are solved.
I sell new clutch kits in my store and I notice they all now package only the needle pilot bearings. So I keep the bushings instock.
Joe

Interesting - since Kiesler requires a needle bearing on their Tremec conversions to meet the warranty conditions. Luckily I haven't had any trouble so far or else I have and it hasn't manifested itself yet!

Frank
kind of reminds me of the computer scenario: it isn't a matter of 'if' a hard drive will fail, just 'when' it will fail...
Bill

And that is absolutely correct.
Now, I must admit I have no personal experience with a Kiesler tranny, so I can't speak to the use of a bushing or bearing with it. BUT, I do have, and have had since 1988, a Richmond 5sp behind a 455 in the Cutlass ---------------------- WITH A PILOT BUSHING-------------- and zero problems.

So, if because of Kiesler's instructions to use only a bearing with their trannys, then the ONLY thing I can suggest to minimize the possibility of a bearing failure is to THOROUGHLY pack the rollers with grease.

Tom Parsons

I was always told, "Bushings wear, bearings FAIL."

I have had a normal pilot bushing fail on my Nova Jerico application. Granted this is a highly abusive application but they still can fail. If someone is having problems with the pilot bushings I would highly suggest dialing in your bellhousing. Hardly anyone outside the racing enviroment does this but on all my stick cars I dial the bellhousing in so the input is in direct alignment with the center of the crankshaft, i.e. pilot bushing. If your transmission input shaft and the pilot bushing on the crankshaft are not in alignment the input will be in a slight bind and will wear out a roller bearing or bronze pilot bushing.

http://i149.photobucket.com/albums/s...ova/Input3.jpg

:iagree: