mating one piece rear main seal inplace of an old two piece engine OMC coupler

[jstcrzyengh]

In response to a concern brought up in my other thread. Will I have an issue mating the new one piece rear main seal engine to the old OMC coupler on an electric shift stringer drive? Any flywheel issues? Anyone know of an adaptor plate that I need or is it as simple as unhook and reinstall. <br /><br />James

 

[jonmurr]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Ford or Chevrolet?

 

[Laddies]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

It should work if the distance from the back of the engine block the the face of the flywheel are the same

 

[jonmurr]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Oh, went back and read earlier post. You have a problem. The old bolt pattern is 3.58" and the new one is 3.00". Your coupler will not fit, as it bolts to the flywheel mounting holes. I' dont have a workaround idea off the top or my head. The only thing you might invgestiate is the fact that they made model 800 stringers untill '86 and the one piece rear main small block came out in '85 so you have a two year overlap there. I dont know if marine engines switched to one piece rear main as the same time, or if the model 800 coupler works on Electric shifts, but it gets you something to start with.<br />Jon

 

[olbuddyjack]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

How does the stringer couplers differ from the Cobras at the splines? I'm doing a similar swap but I'm going the other way, 2 piece seal motor on a 87 cobra drive. If the stringer splines are the same as the Cobra, both of our problems are solved.

 

[Boomyal]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Hmmm! Another poster who asks a question, then never revisits his post!! I would have some input for him but why bother.

 

[olbuddyjack]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Boomyal,<br />Got any good word for me? I've been going through ebasicpowers parts books online and from what I cypher I can use a Merc coupler. Whats your thought. I couldnt find any good news for James.

 

[TwoBallScrewBall]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

I did this. I put a 2002 engine in my 1988 boat, from 2 pc to 1 pc rear main. You need a different flywheel and coupler, no way around it. Check ebay, or I can personally recommend roger at michiganmotorz.com. He helped me out with my project and knows exactly what you are doing and what you will need. Tell him steve from iboats says Hi.<br /><br />Not many people know what you need, and many I encountered in my search did not know either and blatantly told me bad info that would have cost me a lot of $$ if not for my own research and for Roger's help.<br /><br />Good Luck!!!

 

[Boomyal]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

olbuddyjack, Stringer couplers are not the same as Cobra couplers, regardless of the splines. The stringer uses a one piece solid machined coupler and the Cobra uses a two piece coupler bonded together with rubber, similar to a prop hub or Mercs style.<br /><br />The two are not even remotely interchangeable.<br /><br />I would follow Stiff Nibble advice. I have no knowledge of the bolt patterns differences between the one and two piece rear main seal cranks. I find it hard to believe there is a difference however.

 

[Buttanic]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

The one and two piece seal crankshafts are different believe me. Also the flywheels are different. The one piece flywheel is counter balenced and the two piece is not. Some engines went to the one piece seal in 1985 but the 5.0 and 5.7 V8 changed in 1986. This information is direct from Chevrolet.

 

[TwoBallScrewBall]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Boom, the bolt circles are definitely different going from the 1 pc seal crank to the 2 pc seal crank. Trust me. <br /><br />The engine in my 1988 boat, which was either a 1987 or 1988 block, still had a 2 pc rear main seal.

 

[olbuddyjack]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Thanks Boomyal,<br />I'm not at all familliar with the stringers. After looking at some parts diagrams I can see theres a big difference! About the only thing the same is the OMC logo.<br />I think I got my problem worked out on another post. Thanks guys!

 

[Buttanic]

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

Re: mating one piece rear main seal inplace of an old two piece engine OMC coupl

I belive what happened is GM started putting one piece seal engines in their cars and trucks and the remaining stock of two peice seal engines went to marine and replacement engines for for older vehicles. That why you find two piece seals in marine engines after 1986.