Sorry if this has been covered before. I did try the archives to no avail. I have a '56 265" SBC which I am trying to hook to a three speed Saginaw. The hole in the crankshaft is smaller than the pilot bushing which came in the clutch kit I bought. The pilot bushing is approximately .040" bigger in outer diameter than the hole in the crank. No, the old bushing is not in there. Yes, I checked three different pilot bushing OD's, and one parts guy said that GM has used the same pilot bushing in all the Chevrolet motors going all the way back to 1932. All I can figure is that in the early Chevrolet V-8's GM had Powerglide crankshafts and a manual transmission crankshaft. Could this be? The motor is freshly rebuilt, and I expect to have a chat with the guy on Monday, but . . . well, I'm probably the only one here impatient, right? Any help or solutions appreciated. Thanks in advance, GA
Chevrolet did not machine the crankshaft if a automatic transmission was attached from the factory...hence the smaller hole....autoparts used to carry the undersize bushing....none of the current books list this bushing...try finding a old autoparts store...
I seem to recal that they did have different cranks for a few years, seems you could machine the bushing smaller a lot easier than you could make the crank the right size. Might screw you up next time you need to replace it, but that won't be for a while will it? The 59 parts book lists a manual trans crank as the replacement for all the early V8s, notes that you should remove the pilot bushing from the crank for PG cars
Powerglide crank is different. Dorman and others make a bushing for the swap to standard. (Dorman p/n 14651) OD= 1.060" instead of the standard 1.096" Rockauto (online) sells them............ also might try your local NAPA.
Hi "43", you need a Pioneer pilot bushing part #PB-656-P. This is a "conversion" bushing for the early "glide's" to the later stick trans. If you can't find them drop me line (e-mail), have a bunch on hand! The dimensions on the late bushing is 1.094" x .592" x .750". The one you need is 1.065" x .592" x .750". The difference should be around .030". Thanks, Gary in N.Y. P.S. You could always machine down the later one, should be fairly straight-forward for someone with a decent lathe!!
You guys are awesome! Thanks. I thought it was me, glad to hear it isn't. Well, mostly isn't! Anyway, as usual, I come away a little wiser. Thanks again to everyone. GA
43, the dorman part # is 690-035. It is shown in the book as 57 to 61 conversion bushing, used when converting from powerglide/turboglide to manual trans. It is stepped so that it fits in the large machined area of the crank where the torque converter pilots,,because that is the only area that gm machined on these cranks. Kinda funny it took them 4 years to figure out that they needed to machine cranks to fit both std and auto cranks ! Dave
Hi Dave, "heads-up", two different bushings, one for the "Powerglide", another for the "Turboglide"! The Pioneer part #PB-656-R fits the "Turboglide" cranks. This particular piece is "stepped". The part #PB-656-P is not a stepped deal! It appears the same as the standard Chev pilot bushings. Thanks, Gary in N.Y. P.S. There is also another bushing for the Corvair swap, this is a Pioneer part #PB-656-C, not in demand much anymore!
I've used this bushing before, the case is that the crank was drilled but not machined, so hopefully the drill didn't walk. I guess you could check it with a dial indicator, but I just drove mine in and never had any problem. Which brings me to my point, this bushing will be a bit large still, as they can only get so precise with a drilled hole, so there may be some bronze shaved off when installing. This is going to require a tool that fits between the part and a large persuader, but it also puts undue stress on the thrust surface of the rear cam bearing, so some sort of back-up is recommended.
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