3.8 exhaust cracks omc

[itsneverfinished]

hello, i am new to the site and also a new boat owner.
i have an 85 beachcraft with a 3.8 omc v6. i am trying to do some preventative maint. and some restoration. i was almost finished until i decided to change the exhaust tubes, they were dry rotted.

i pulled the risers and they look terrible. i could clean them up, but i decided to pull the manifolds to inspect them. both rear ports on both manifolds have long (inch or so) cracks.

the manifolds are rear risers, and i cannot seem to find replacements. i can find 4.3 manifolds all over, but they are center risers.

questions are:
1. can i use center risers?
2. is a 4.3 and 3.8 the same exhaust port pattern? it looks like it.

thanks brandon

 

[havasuboatman]

Re: 3.8 exhaust cracks omc

You can use center risers, but you will then have to find a set of exhaust elbows to turn the exhaust down into the "Y" pipes. As for the exhaust manifolds port alignment, to the best of my knowlege, the 4.3 and 3.8 are the same. But I am not certain on that.

 

[itsneverfinished]

Re: 3.8 exhaust cracks omc

thanks,
i figure i can rig something up, the rubber tubes arent expensive and come in many configurations.
i guess my main thing is do 3.8 and 4.3 manifolds bolt up for sure?
any help is appreciated

 

[itsneverfinished]

Re: 3.8 exhaust cracks omc

i believe this setup will do me right, my manifolds exit at the rear and turn down and aft from the risers.

 

[Kovah55]

Re: 3.8 exhaust cracks omc

Here is the setup from crowley marine.
http://www.crowleymarine.com/brp_parts/diagrams/30717.cfm

 

[Howard Sterndrive]

Re: 3.8 exhaust cracks omc

i believe this setup will do me right, my manifolds exit at the rear and turn down and aft from the risers.

that's what you need.
Osco is the only brand that will clear your power trim engine mounts.

 

[Kovah55]

Re: 3.8 exhaust cracks omc

I posted the oem diagrams, because i wasn't sure the osco manifold would clear the valve covers.Will they ?

 

[MikDee]

Re: 3.8 exhaust cracks omc

Is it a Buick 3.8 V6, or a Chevy 3.8 V6, I believe OMC used both engine designs, and I think the manifolds are different!

 

[Howard Sterndrive]

Re: 3.8 exhaust cracks omc

I posted the oem diagrams, because i wasn't sure the osco manifold would clear the valve covers.Will they ?

Yes they will. The Osco's clear the OEM valve covers.

It's Chevy, MikDee.
Brandon's boat is 13 years newer than the last OMC/Buick combo offered.
But you are correct, the Buick manifolds are totally different.

 

[itsneverfinished]

Re: 3.8 exhaust cracks omc

so ther consensus is the osco kit, yay, 1000 dollars.

thanks everyone for the insight. - btw if anyone knows where to get this osco setup any cheaper please let me know

 

[Kovah55]

Re: 3.8 exhaust cracks omc

You have a pm

 

[itsneverfinished]

Re: 3.8 exhaust cracks omc

no i dont...

 

[Kovah55]

Re: 3.8 exhaust cracks omc

yes you do

 

[Kovah55]

Re: 3.8 exhaust cracks omc

heres another one

 

[itsneverfinished]

Re: 3.8 exhaust cracks omc

syke, yeah i do thanks man

 

[Kovah55]

Re: 3.8 exhaust cracks omc

Your welcome