1pc or 2 pc rear main seal?

[Artemis Entreri]

Hey, how do you tell if an engine is a one piece or two piece rear main seal?? Ive got a block here, I dont remember for the life of me how to tell and the guy looking to buy it needs to know before he decided if he wants it.

Thanks alot guys.

 

[4X4HIGH]

The 1 piece rear main seal has an aluminum seal adapter that holds the seal and bolts to the rear of the block.

 

[Artemis Entreri]

Uhh, no idea, lol. Can you tell from this picture?

The code says its a 80-85 block, so does that auto mean 2 piece??

 

[odin]

Looks like a 2 piece to me.

But take a pic from the bottom rear of the engine so we can see it better.

 

[USSkoval]

Yes, 2 pc

 

[Artemis Entreri]

Blah, not what I wanted to hear,thanks though.

Is there a converter or something he can buy to go from a 2pc to a 1pc RMS?

 

[Randy92782]

don't the one pieces start in 85? Then maybe the centerbolt valve covers?

Atleast that's what my Blazer had in it at one time

 

[USSkoval]

'86 got 1 pc, then '87 got centerbolt covers.

 

[Randy92782]

'86 got 1 pc, then '87 got centerbolt covers.

coulda swore mine was an 85 motor out of a van

Been wrong before though

Think you're right about the centerbolt valvecovers also. Mine was already affixed to with a carb so maybe it was actually an '86 motor

 

[4X4HIGH]

86 was the first year for 1 piece rear main seal, 87 was the first year for centerbolt valve covers and the intake manifold bolt angle change and FI.

 

[Randy92782]

Also can you get a pic of the actual casting numbers on the top of the block by the left head??

 

[4X4HIGH]

The easiest way to tell a 1 piece rear seal engine is just look at the end of the crank, if it's a full round it's a 1 piece, if it has a flange offset then it's a 2 piece seal.

 

[Artemis Entreri]

Yea, its definantly a two piece, can tell by the crank now that I know what im looking at.

Is there anything he can get to go from this 2 pc block to his one piece trans??

 

[USSkoval]

Yea, its definantly a two piece, can tell by the crank now that I know what im looking at.

Is there anything he can get to go from this 2 pc block to his one piece trans??

The correct flywheel/flexplate.

 

[4X4HIGH]

If he's wanting to swap this engine in place of a 1 piece rear engine the only thing needed will be the correct flywheel/flexplate for an 85 and earlier engine since the 86 and later won't fit that crank.

 

[Artemis Entreri]

Oh, I thought it was a bigger deal,nice, thanks.

 

[gone huntin]

I just finished doing the same swap over, but the other way around. I put a one piece block in place of a two piece. I have an almost new heavy duty auto flexplate/flywheel for the two piece that needs a home.

 

[chevyuser74]

why wont the 1pc flywheel bolt up to the 2pc block? and what if it does?

 

[USSkoval]

why wont the 1pc flywheel bolt up to the 2pc block? and what if it does?

It's a different bolt spacing. The 2peice has a larger bolt circle. Think of it as trying to put a Cavalier wheel onto an Astro van.

 

[chevyuser74]

so if i have a 1 piece rear seal flexplate bolted up to my 2 peice block what does that mean?