Differences in crankshafts between auto vs stick?

[ScottH]

A friend is having a problem installing a pilot bearing in a pontiac 428 engine. Local parts stores tell him there is a difference in the crank shaft between those made for an automatic vs those made for a manual trans.

Can anyone confirm that this may be his problem? Basically after installing a bronze pilot bearing the manual input shaft will not go into the center hole (did prior to installing pilot bearing). The bearing went in the crank, but was REALLY tight from what he said.

Any info is greatly appreciated. Thanks.

[68 Stepside]

The pilot bearing should be really tight. Is it possible he knicked up the rear surface of the pilot bearing a little? Maybe there's a small burr that's keeping the input shaft from going into the bearing? Did he check to see if the pilot bearing fit on the input shaft before he installed the bearing in the crank? As far as I know, the cranks should be the same, but I can't be 100% sure.

ttt

[crazy longhorn]

I have run across 2 different pilot bushings for the sb chev.....one for the factory stick, & 1 for a auto to stick conversion. Not many of the autoparts guys know about the difference, unless they have been around for a few yrs. even so, the difference is aprox .030, & you would not be able to drive the wrong bushing into the crank. Im not sure what they did on the Poncho's, but on the chevs, I think it may have been a tolerance issue(the hole was a little oversized, & it didnt really matter if the crank was to be used with an auto trans behind it?) good luck,crazyL

[Hooter]

whatever you dont hammer the crap out of the crankshaft, that is a very very bad thing to do

[Frank_Zeller]

He should be using a bearing not a bushing.
Request one for a 69 Firebird with 400. I have The part number some where if he cant find one.


I've heard of some later model Pontiac cranks not having the hole finished out completely. But none of the early stuff. Pontiac used the same crank for std's and automatics.

[Hotrodhenryj]

Are you trying to put the trans in with the clutch in or just checking to see after installing the bushing. If the clutch is not lined up correctly it could give the indication that its not going into the bushing. The best tool to do the alignment is an old input shaft of the same demensions.

[ScottH]

Thanks to all for your replies and info. The input shaft was tested prior to installing the pilot bearing and it fit fine. The bearing that he bought was from a local parts store for his application.

Any other thoughts, ideas, observations ?

Thanks.

[crazy longhorn]

if you dont find any other solutions, you might check for burrs as 68 stepside suggested......& also make sure there is a good chamfer on the lead in edge of the hole. I think I would "mike up" the hole & the OD of the bushing, & if needed have a little skinned off the Od of the bushing. You shouldnt need more than about a .002 press fit on the bushing. Good luck,crazyL