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:

See post #9.

Muncie and Richmond trans have a lot of slop in the input shaft which makes bellhousing alignment somewhat more forgiving. Later trans like the TKO, T45 and T56 do not. These will destroy a pilot bearing in short order and will quickly wear out a bushing if the bellhousing is not within their specified runout dimensions.

An added benefit of concentricity is ease of shifting, especially at higher RPM's.

GM issued bellhousings are notorious for "marginal" and excessive runout as relates to use of a modern transmission. Not surprising, as everything from GM, back in the "good old days" had huge tolerances and very poor quality control.

That is a required step before doing the Keisler Tremec conversion !!
Fortunately my '61 did not require any offset dowels, etc.. and was well within specs..

My Tremec 600 didn't come with a needle bearing bushing. It came with an aftermarket-looking, silverish-colored bushing, which I chucked for a good bronze bushing from GM.

Dave

Pilot rolling bearing
 

pilot bearing or bushing. My change over from auto to TKO 600 manual about 8 years, 10k miles ago in my 91 12cyl Jaguar (please no jokes) came with the pilot bearing in the kit from Driven Man. I didn't dial in the bellhousing center line, should have but didn't. Fast forward to last year, needed throwout bearing work. Long story short, very lucky I guess. The pilot bearing looked new, repacked it put it back together.
Lawrence

I could never understand why anyone would install something with multiple moving parts, i.e., failure points, when there is a perfectly good one-piece alternative.

Have been running BALL bearing pilot bearings for the past 40 years in all my 4 speed GTO's with no issues and for 100's of thousands of miles, with a lot of abuse. Pontiac specifies a ball bearing, and NOT a bronze bushing. That said, bearings can dry out and fail, and when they do, their hardened parts can wreak havoc on other components. Bushings are 'cruder', but are pretty bulletproof. Have no idea what's in my '61 'vette.

I look at it this way. I got 10yrs to date, still looks new, no noise, vibrations etc. I was not about to "fix something that wasn't broke" or play with fitting a bronze bushing, "been there done that". So, is there an advantage pilot bearing over bronze bushing? I surely don't know. I never had either fail, but this is my first time with a pilot bearing .
Lawrence

I prefer the NON MAGNETIC bronze bushings myself. I have several bronze bushings from clutch kits that a magnet will stick to and i can not bring myself to use them...and purchased the original design which is NON magnetic.

I have also used the roller bearing design on 6-speeds I have done and the Tremec transmission that they required to be used. And when I took out the roller bearing on the 6 speeds I have done it was fine and it was being replaced because the clutch needed to be replaced....and these cars were HIGH miles...50K + miles.

I myself have wondered WHY the design change on this pilot bushing bearing area and someone told me that the roller bearing was more precise. I do not know if I 'buy' that explanation.

I do check the bore concentricity...and correct it if needed.

And I can say that when installing the pilot 'whatever you choose'...I am careful not to damage it in any way so the input shaft does not stick or bind on it...which can cause for problems in the clutch engaging when the engine is running.

I am going to hopefully re-work a press I have made that bolts to the crank shaft and allows me to press the bushing in. It works but it is really crude an the next time I do a clutch and I have the time to do a bit more R & D...I plan on trying to get it 'better'. Right now it takes a lot longer to set it up my tool than tap one in....but it something that i just kinda want to do.

DUB

what would happen if you use a metallic pilot bushing? thanks jim

Accelerated wear on the transmission input shaft nosepiece. See pics about halfway down the page. http://www.crankshaftcoalition.com/w...g_and_bushings

Larry

I've never heard of a ball pilot bearing..
Bill

Most have needle bearings............but a Google search does show a few ball bearing pilot bearings that are out there in cars.

Larry

Who or where is a good source for the bronze or oilite pilot bushings?

I did a TKO 600 conversion on my '71, and used the supplied pilot bearing. I was skeptical...

I don't have many miles on the setup (< 1000mi). It will be coming out soon for a engine change and I would like to use a proper bushing in the new engine, rather than the bearing, and will dial out the Quick Time bell as well.

Carter

I believe some Olds engines used a BALL BEARING pilot bearing. AND, with that said, MANY Olds engines (such as later 455 cranks) are NOT machined for a pilot bushing/bearing because MOST Oldsmobile cars came with an auto tranny (puke, puke, puke), thus, no need for the crank to be machined for a pilot bearing/bushing. When I sent the 455 for the Cutlass to the machine shop, I did not know this. Purely by accident it was mentioned to me that there was no pocket in the end of the crank for a pilot bushing. So I had the machine shop cut the pocket and install a bushing that I furnished. This was back in 1988, and I have had ZERO issues with a bronze bushing in the 455 with a Richmond Street 5sp.

Just about all of my project cars have been Chevys and never ran across a factory ball type pilot bearing until I was reassembling my '64 GTO. It kinda looks like a small ball type axle bearing. Since the GTO was put together around 2002, I've only put a couple thousand miles on it and no problems. After the disintegration of the GM needle pilot bearing in my 66 L79, I won't be using that style anymore in the Chevys.
Mike T - Prescott AZ

pilot bushing concern
 

I don't mean to crash this thread but I have a question. I replaced the bronze pilot bushing in my 59 but could not get it far enough in to be flush. It is out by 1/4 of an inch. I was told the tranny would hold it in place. Is this going to be a problem? 59 navy

Navy, it needs to be all the way in. The trans is not supposed to hold it in place....if it is, the mainshaft shoulder is jammed up against the protruding bushing, causing unwanted pre-load on the trans. Whether bearing or bushing, I always place it in the freezer for an hour or so so that it taps right in easily. Works like a charm.

Bushed
 

I ignored Keisler warranty requirement for the Roller pilot on my SS700 Trans. I "DID" however dial in the scatter shield run out to +/- 0.003 . Great product below
http://www.robbmcperformance.com/products/dowels.html


Napa # for the Bronze Pilot Bushing. BK 6151161
and O'Reilly store under the Federal Mogul # PB-656-HD.
Be Sure to take a magnet with you and verify it's Non Magnetic.( No Iron )
Please Note: the pilot Bearing/ Bushing only come into play when the clutch is disengaged, pushed in. :yesnod:

In my Nova with a G-Force G101 transmission the input shaft splines are cut back farther which allows the use of a large ball bearing type to be used. NOTE: You can't use this on regular Muncie or ST-10 transmissions. So there are applications where a ball bearing style is used. The bearing has a collar that presses into the back of the crank in the space where a torque conv snout would normally go.
https://cimg3.ibsrv.net/gimg/www.cor...9d7487d565.jpg

That information is in the archives, and I think was also a recent thread here. So check past threads. Here it is: https://www.corvetteforum.com/forums...t-bushing.html

GM still sells one, although it is a bit different than the 1950-60 originals. Also contact Autogear, who participates here on this C2 forum. They say they have them for sale. Probably better than the new GM ones. :thumbs:

Larry

Excellent comments, only use bushing, same performance or better. much less risk of failure.

Thread from 7 years ago. Might be time for a new one.