OMC Cobra 3.0l 1993 to 1986 engine swap

[nixby]

Need some help, I have a 1993 Caravelle 1750 fs that I am changing the motor on. I pulled out a 1992 OMC 3.0l (302CMRAMK) and I have a 1986 OMC 3.0l (302APKWB) to go in it.

Off the bat I noticed the exhaust isn't going to line up with the elbow. I looked at buying the 1986 exhaust pipe but it looks like that pipe will not marry up with the transom plate properly, although it looks like the 1992 transom plate is the same p/n as the 1986 transom plate.

Orginally I planned to rebuild the 1992 motor, but I found the 1986 cheap and decided to scrap the rebuild idea, so I have the entire 1992 motor still in pieces.

Basically, my question is... can I make this work? It looks like I can put the 92 manifold and riser on the 86 block, but will that cause any other problems? Do I need to put the 92 carb on as well? then the 92 fuel pump etc...? does the cycle end?

I appreciate any help or advice, thanks!

 

[nixby]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

I've done a little more research and found there a little to no interchangeable parts between these two motors and drives, even though they are both extremely similar. I can't really figure out how to proceed without finding a matching transom plate/outdrive or bending the exhaust pipe to align it with the riser.

 

[Bondo]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

I've done a little more research and found there a little to no interchangeable parts between these two motors and drives, even though they are both extremely similar. I can't really figure out how to proceed without finding a matching transom plate/outdrive or bending the exhaust pipe to align it with the riser.

Ayuh,.... Welcome Aboard,.... The Long Blocks are nearly identical,...

You should be able to swap over All the accessories from the newer old motor, to the older, new motor,....

You'll need a conversion coupler to complete the package,....

 

[nixby]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

Conversion coupler? What necessitates that? When I put the 86 motor in the boat the coupler aligned properly with the gimbal bearing and it looked identical to the 92 coupler.

The manifold/head connection is different between the 2 motors but the head/block connection is the same so right now I'm thinking I will get the 92 head checked for cracks and flatness and then put that head on the 86. Then I can put the 92 manifold, riser, carb, etc... on and I think it should connect up to the exhaust/work properly?

 

[Scott Danforth]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

the cranks are different. hence the need for a conversion coupler

 

[nixby]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

Where could I find one of those?

 

[nixby]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

I'm doing a pretty much identical swap right now, curious how it worked out for you? Did you use the 92 head on the 86?

 

[Howard Sterndrive]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

if your 1986 engine came with the 1986 coupler on it, you're good to go, you don't need to buy a coupler.

 

[nixby]

Re: OMC Cobra 3.0l 1993 to 1986 engine swap

Ok great, thanks howard