mutzman951

Is there any way to tell what year an engine block was manufactured, other than the stamp on the rear, forward of the flywheel? My engine is installed, and there is no way to access the stamp at the aft end.

Here's my problem; I cracked the block in my '89 951, and replaced it. I am having balance shaft problems on the rebuilt engine. When torqued to specs, the top shaft will not turn and tears up the belt, and when left loose enough to rotate, the rear bearings spin and tear up. I have tried 3 sets of bearings including the used ones from the old block, with no success.

My old (89) block is stamped on the aft end, and also has the numbers "0046/3A" and the replacement block has "0046/2A" on it. Is the "2A" an indication of the block being an '86 engine block? If the difference is the year '86 vs. '89, that would make sense, as the balance shaft rear half bearings are different part #'s.

Any help would be appreciated, as I am at my wits end.

Thanks!

doug

Sam Lin

When you replaced the block, did you use the balance shaft covers that came with the new block? They are align bored as matching parts and each block must remain with its original covers.

Sam

horsepowerfarm

The blocks are different '89 vs '86. Like Sam says, where are the balance shaft covers from, the '89 block or '86 block?

mutzman951

The balance shaft covers are from the original 1989 block. The block I got was bare. I don't have the number for the guy I got it from

I guess the fundamental of my problem is: Is the difference between the '86 vs. '87 and up part number for the balance shaft bearings a difference in size? Would that size difference in the bearings make my problem go away?

I'm thinking that I'll just order the '86 bearings from Zims and try them.

Any suggestions?

Thanks again!

Doug

macnewma

Basically, what Sam is saying is that the balance shaft covers are an integral part of each specific block. They are not interchangeable. Well, I guess there is a 1 in a million chance they will match up.

I am not sure of part differences, but you really can't even switch within a model year. Maybe there is a way to machine them to match. Your best bet at this point might be to delete the balance shafts.

Chris White

You can’t swap covers….try and track down the original covers.

Chris White

mutzman951

Back to the original question...

Is the "0046/2A" code on the block indicative of an '86 block?

I cannot get the original upper balancce shaft cover.

Alternative advice anybody?

Thanks!

Doug

Sam Lin

Doug, the covers are bored to EACH INDIVIDUAL block. Even if you find another same-year block, even if it was the next block in the assembly line, it still will not match up!

Sam