4.3 OMC Batwings

[Alexjfri]

Good morning all,

My apologies as I know this has been posted about time and time again, but now parts are limited.

I just purchased a 1986 Doral 20FT. 4.3 GM OMC COBRA. Engine Tag: 432APWX

Both batwing exhaust manifolds are cracked, and I'd love to get back on the water this year.
I did confirm no water has entered the motor.

My question is this, the only thing I can readily purchase is below. (Located in Canada, Freshwater only)

Barr OMC/Volvo Center Rise Exhaust Elbow - OMC-20-913784​

Item: #1144898 | Part Number: OMC-20-913784

Barr OMC/Volvo Center Rise Exhaust Manifold - OMC-1-3857656​

Item: #1144893 | Part Number: OMC-1-3857656

I believe I will also need the Volvo down pipes - 3854874 as some of the research I have read is the GLM down pipe causes fitment issues with power steering.

Has anyone done this exact conversion or can confirm these parts fit? I can not find any of the rubber fitting part numbers that would also be required.

Any help would be much appreciated.

First boat is not off to a record start.

Thanks for any help offered.

 

[Lou C]

They will fit, I did it 9 years ago on my 1988 4.3.
However, if the manifolds are cracked, better check the engine itself and the intake manifold! Why would someone drain the engine and not drain the manifolds, doesn't make any sense!
The Volvo down pipes are pretty pricey new, you can find good freshwater used on Ebay, or try NLA Marine parts.


bottom pic is test fitting the Barr Manifolds and Volvo down pipes and hoses that's why one bolt is missing in the pic lol.
I'm in salt water and will probably will replace them this fall or next spring because I'm in salt water. I did figure out a way to check the inside of the joint between the elbow and the manifold to see if water is leaking in by using an endoscope camera. There is a small fitting on top of the elbow you can remove and the camera wand will fit right down there.

 

[Alexjfri]

Appreciate the reply. Do you happen to have the part numbers for the rubber bellows required or is it the same as what I have?

 

[Lou C]

not off the top of my head but if you look on a volvo parts website you should be able to find it. I bought all new Volvo parts when I did it and it was fairly expensive but it all fit perfect and no leaks, so it was worth it to me. The Barr kit with manifolds, elbows, and hardware/gaskets is about $1,000 USD now, when I did it back in 2017 it was about $750.
Just make sure the rest of the engine is OK before spending all that cash though.
Look here, these are OMC part #s but in that time frame they were in a joint venture with Volvo so the #s and parts are the same.

https://www.marineengine.com/parts/omc-parts/omc-boat-parts.php?year=1998&hp=4.3&model=434BPBYC&manufacturer=OMC+stern+drive&section=Exhaust+%26amp%3B+Cooling

looks like the down pipes really went up in price, they were like $200 each when I bought them. I'd look for freshwater used, they were used on a lot of boats with 4.3s. Even my salt water used ones are in very good shape, they don't seem to corrode at all. Must have used a good grade of aluminum.