1984 3 liter mercruiser

[rolmops]

I found another 140 horse engine for my boat and right now I am in the middle of completely overhauling it. One thing I need to replace are the piston rings (the engine was frozen and although it came loose, the rings were stuck up to the point where they broke while being eased out. The rings I need are 0.030 oversize and I want to order them right here here on I-boats. Does anybody know the sierra # for 1980s mercruiser 140 0.030 oversize rings? Is it 18-3938 or is it 18-3941?
Thanks, Cornelis.

 

[achris]

Re: 1984 3 liter mercruiser

Neither.

The 18-3938 are for 4.3/SBC, and the 18-3941 are for BBC....

I've looked on iBoats and it looks like they only have the V6/V8 rings.

I'll have a search of some other places and see what I can come up with... Stand-by.

Chris......
BTW, nice to see you back...

 

[Bt Doctur]

Re: 1984 3 liter mercruiser

rings is rings, all you need is the bore size and piston size.

 

[Bt Doctur]

Re: 1984 3 liter mercruiser

you say you need .030 oversize. What is the bore dia.? dont you mean you have .030 oversize pistons?

 

[achris]

Re: 1984 3 liter mercruiser

From what I can see, Sierra (and Merc) don't make .030 rings for that engine, they do .020, Sierra number 18-3939, Merc number 39-66217...

Chris.....

 

[rolmops]

Re: 1984 3 liter mercruiser

Yes I do have the 4.030 oversize pistons

 

[achris]

Re: 1984 3 liter mercruiser

What brand piston?

 

[rolmops]

Re: 1984 3 liter mercruiser

The only thing that is printed on them is B3081

 

[rolmops]

Re: 1984 3 liter mercruiser

The only thing that is printed on them is B3081,but I think think that I solved my question. The engine block is chevy made and it is a 4.030 bore. the Chevy rings for 4.030 are # 14089026 which cross references to sierra 18-3938.
Thank you guys for your help and efforts.
Chris, I never left,but forever answering the Johnny rude questions became a race as to who answers first and there are a lot of good people answering already ,so I just moved to the side. Besides,I started competitive king salmon fishing and moved up to a bigger boat (Starcraft Islander) with an I/O and I am just learning about 4 strokes which are very different from ancient 2 strokes.
Since bad advice is way worse than no advice, I just started lurking instead of posting.
Cornelis

 

[achris]

Re: 1984 3 liter mercruiser

....
Chris, I never left,but forever answering the Johnny rude questions became a race as to who answers first and there are a lot of good people answering already ,so I just moved to the side. Besides,I started competitive king salmon fishing and moved up to a bigger boat (Starcraft Islander) with an I/O and I am just learning about 4 strokes which are very different from ancient 2 strokes.
Since bad advice is way worse than no advice, I just started lurking instead of posting.
Cornelis

I know that feeling... What with Bond-o, Fun Times and the Doc, I hardly got a look in. Especially since most of the new questions were posted while I am sleeping. And if those guys didn't get them, Don snapped them up pretty quick. I'm pretty much left with either the later nighters (morning here) or the dregs nobody else wants... (no offense intended to anyone)....

As for I/Os being different, oh yeah!!! It's like going from an old lawn-mower to a modern car (especially the newer MPI stuff). But I gotta a secret, it's all about 'suck, squeeze, bang, blow'...

Cheers,

Chris.....