OMC overhaul and Riser 3.8l

[beanhauler]

Just undertaking the overhaul of a 3.8l OMC with the original selectrim rams.
Having taken the manifolds and heads off found a generous coating of rust all over the pushrods and rockers.
The manifolds look like they are shot as there is a lovely coating of rust inside them and water.Two springs have snapped also.
The heads are being overhauled no problem but the manifolds may be grief.
Question is that these manifolds are no longer available and i think i have the part number 0910114/10156
The manifoldsfrom the 4.3 fit as far as the ports are concerned but have the idea that maybe the manifolds may hit the selectrim rams.
Just need to be sure that if you fit the OMC643 osco replacements for the 4.3
they will not hit the rams.
Anyone tried this?
Any ideas gratefully received.

 

[chiefalen]

Re: OMC overhaul and Riser 3.8l

Off the top of my head without looking anything up cause you didn't give a year for this boat, is that the 4.3 is indeed interchangeable. Manifolds that is.This is a stringer model, Correct?

And i don't see why they would prevent the operation of the rams, however the lower mounting point i believe can be moved to allow proper operation of the rams.

Than again i'm not lookin in the engine bay.

 

[beanhauler]

Re: OMC overhaul and Riser 3.8l

Thanks for that

I think i may be able to do some wrestling with a mercruiser manifold and re juggle the water inlet.
Looks like it might fit.

Actually i have run into a new problem

The heads are being overhauled but the shop that is doing them are automotive only.
Worried that if they replace the valve seats and valves they might stick in auto ones.
Does anyone know if the auto valve seat s are different to the marine version
or if the valves themselves are different?

 

[fendersfender]

Re: OMC overhaul and Riser 3.8l

Should be the same......let us know the results from your exhaust manifold problem....I have twin 3.8L OMC's that are pushing 25 years old....I know i'm ushing my luck with these manni's....good luck..........P.S. someone here has converted manifolds for a 3.8---maybe he'll chime in

 

[beanhauler]

Re: OMC overhaul and Riser 3.8l

Should be the same......let us know the results from your exhaust manifold problem....I have twin 3.8L OMC's that are pushing 25 years old....I know i'm ushing my luck with these manni's....good luck..........P.S. someone here has converted manifolds for a 3.8---maybe he'll chime in

Will do ...i'm getting the heads on next week sometime so can have a measure up.Hopefully in the new year we will find out if everything fits

I've posted an item about head torques and a few pictures of the manis in this forum .