main bearing cap help

[rgtrough]

Hey guys, I'm Baaaack.
Well the nice weather is just about over here in southwest Ohio, so the '74 is parked and I am looking for new projects.
I have agreed to help a friend with a mild rebuild of a '79 (I think) 355 cid. He disassembled the engine with out marking the main bearing caps. Can anyone supply me with the correct which one goes where? They are GM with #119 on
two of them, 122 and 128 on the others.
As always thanks for being here for guys like me. peace :cool

 

[Tom B Hargrove]

Bad news, but you can't tell by those numbers. Possibly a machine shop can solve your problem, by align boring the block's crankshaft journals. If the block was ever rebuilt, it might have been marked, some mechanics use a series of dots, or a stamping number that can be very light. Look closely. Good luck.

 

[black_81_vette]

Yeah id agree if the caps were not marked theres a line hone or bore in the future for that block.And when thats done youll need a special timming chain thats used for blocks thats been machined like that.

 

[rgtrough]

Hey guys, thanks for the feedback. I was afraid this was going to be a problem. The good news is there are other blocks available to us if this gets to costly.
again thanks. peace Bud

 

[Jack]

The rear main is unique amongst the 5 so it's pretty obvious. If your pal has saved all the bearing shells and if crank's journals and caps' bores are undisturbed you may be able to match them up. Also, most caps have a raised arrow (albeit sometimes faint) that points to front of motor. Match witness marks from backside of shells to caps' bores ... then match witness marks from crank journals to shells' wear surfaces. Take care not to wipe away marks from cap bores and shell backsides ...Use only oil or trans fluid with soft cloth or fingertip to clean with. G'Luck.
JACK:gap