Pilot bushing question.
There is an interesting post on the other forum concerning different size pilot bushings. Also mentioned is that crankshafts were made with different pilot bushing holes for different transmissions. Did GM produce crankshafts with different size rear center holes for different transmission applications and were engines built with different pilot bushings. Sounds like a inventory nightmare.
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Re: Pilot bushing question.
Bruce -
The only instance I'm aware of where the crankshaft was machined differently for a transmission application was the crank used in Turboglide engines, which had the pilot area machined larger and deeper to accommodate the much larger pilot on the Turboglide converter housing.
That said, I've heard of cranks from some Powerglide engines that wouldn't accept the GM standard pilot bushing (and Dorman makes an adapter bushing for that problem), but I've never encountered one myself, and I've built a fair number of 283's and 327's since 1965. -
Re: Pilot bushing question.
Bruce, like John I have done 283's and fewer 327's , all manual transmissions, and found all to be the same. I did an L-82 TH 400 but don't recall size. How is the Hilborn car running?SteveComment
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Re: Pilot bushing question.
Steve, Thanks for the additional info. Am I nuts or what, automatic transmissions use a flexplate to which the torque convertor is attached--- so there is no need for a pilot bushing. Is that correct?? The Hilborn 62 is running great. I drove it to Goodguys in Indy last year and just got back from Goodguys at Columbus , Ohio. I am restoring/assembling a 57 Corvette Gasser and I believe the Hilborn or a Rochester FI unit will go on it. Decisions, decisions, ain't it great. Good hearing from you, Bruce BComment
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Re: Pilot bushing question.
When I had my 59 283 engine rebuilt last year, the machine shop replaced the crank without consulting me first. When I went to install the pilot bushing, it would not fit into the crank. I went back to the LAS store thinking I had been given the wrong one. We could not find 1 to fit and I had to take the listed bushing to a shop with a lathe that could turn down the outer dimensions to fit into the crank. Not sure what the deal was here, but the bushing definitely would not fir without turning it down several thousands.Comment
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Re: Pilot bushing question.
Al,
Maybe the bushing was out of spec. Possibly a "imported" item.
The chance of the crank being wrong is pretty slim, but possible.Comment
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Re: Pilot bushing question.
Bruce, the ones tried were either too large or too small on the OD. The old guy that used to work there many years ago, came in when we were going thru the pilot bushings. The employee who was helping me (has been in the parts for around 28 yrs) asked him if he had ever encountered this. He thought for a minute or two and said he had, and that they had to machine 1 down to fit a 283 or 327 crank back in the early to mid 60s at a shop that is no longer in business. I don't know if this crank is/was a Chev, Buick, Olds or ?. I do k now when the engine was started, the bearings quickly went south. I'm currently awaiting the rebuilt (once again) engine from him to be installed by his crew.Comment
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Re: Pilot bushing question.
Guys ,
Some great information.
I just assembled my 327 for the 57 gasser and the engine is/was a 1964 passenger car engine that had been previously built with popup pistons, bored , etc.
I got a chain auto store (Advanced Auto) Perfection clutch set (Chinese) which included a bronze pilot bearing and it fit and functions as it should. I guess I was lucky.
Actually the clutch disc in the gasser from 1969 was made by Perfection, I believe they were located in Chicago.Comment
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Re: Pilot bushing question.
Thanks Robert for that info. That would explain it, I guess. I know it was a headache to reload the engine and take it to a machine shop to have the bushing fitted to the crank after finding one that would take the time to do it--And they did this at a very reasonable price at that!!!Comment
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Re: Pilot bushing question.
Count me in. Backstory - 30 years ago I acquired my '61 from original owner that came with a replacement engine (LT1 actually). My restoration knowledge not very deep at the time, I thought I would replace the LT1 with a "correct" engine out of a '61 donor car, I not know castings et al not "correct". I bought a '61 full size Chevy with 283 and automatic transmission, ******ed the engine and towed the rest to a junk yard. Pull flex plate, install flywheel, and then try to insert pilot bushing - no fit. I tried everything. Finally in frustration ground it to fit. So I watch these threads and smile when people say these things don't exist - they do. Wish I had known about that Dorman part back then.Tom BradyComment
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