omc 3.8L exhaust manifolds

[fendersfender]

will be repowering my boat later this year....'85 searay 255 amberjack w/ twin omc 3.8L....i suppose i should also replace exhaust manifolds since mine are 20+ years old.....problem is that i cant find any....has anyone used 4.3 manifolds...if so, what modifications were necessary? my current manifolds are in good shape (i can hold a hand on risers without burning my hand), but with a repower i feel i should put new manifolds on.....any ideas?

 

[whywhyzed]

Re: omc 3.8L exhaust manifolds

I have 1 set of new 3.8 manifolds and risers. I will sell for the same price as OMC wanted in 1994.

 

[fendersfender]

Re: omc 3.8L exhaust manifolds

unfortunately, i need 2 new sets.....unless i can find another new set somewhere.....thank you

 

[WillyBWright]

Re: omc 3.8L exhaust manifolds

Are you getting another pair of 3.8s? I think I'd upgrade to 4.3s if I was spending the money anyhow. Everything should bolt-up just fine. You might need to change carb jets, but that's about all. New manifolds and risers for sure. New water pumps and exhaust flappers too. I believe the 3.8s and 4.3s use the same manifolds.

3.8s are like smallblock 5Ls minus two cylinders. 4.3s are like smallblock 5.7Ls minus two cylinders. They use the same V-6 block with different bores.

 

[KaGee]

Re: omc 3.8L exhaust manifolds

I would definetly replace them. I took the chance and one puked out before I even had 30 minutes on the new engine.

Look at my pics to see the OSCO replacement & mod I used.
OSCO is THE only set that will clear the front SELECTRIM rams. You could use the same thing for the 4.3, but you need to buy the shim kit to clear the valve covers.

 

[fendersfender]

Re: omc 3.8L exhaust manifolds

kagee.......are those risers taller than the spark arrestor....the reason i ask is that my spark arrestors just clear the top of my bilge.......

 

[KaGee]

Re: omc 3.8L exhaust manifolds

I don't recall, I can't check till I can get under the cover. It's close.

 

[fendersfender]

Re: omc 3.8L exhaust manifolds

hey all...Doug Russell Marine is listing part numbers and prices for oem manifolds for the 3.8L...although it would cost me around $2400 for two engines...WHEW!!!!..i have a hard time believing that they would really have those in stock (if they do, they are the only ones on the planet)....if i go the way of KaGee, it works out alot cheaper.....hey kagee...where did you find the best prices for the osco manifolds, risers, and elbows? i am assuming that the elbows are 80 degree, as that is all i can find...that setup of yours looks do-able as long as the're not too high...but, in reality, the should'nt be too much taller than the originals, i would'nt think????

 

[Gary H NC]

Re: omc 3.8L exhaust manifolds

Geeze,1200 a set from Doug Russell :%:^:^

They are always wanting top prices for their stuff!
After they charged me 18 bucks for 6 lock nuts i won't buy from them again..

good luck with your manifolds..8)

 

[KaGee]

Re: omc 3.8L exhaust manifolds

Ended up at Boatfix because IBoats did not have.

Yes, the elbow is 80* and adapts the hose size too. Bought the corrugated hose on EBay. Bought the elbow kit, it includes the hose from the elbow to the riser and hose clamps.

 

[fendersfender]

Re: omc 3.8L exhaust manifolds

kagee...i will be in your area in may...we are chartering on lake erie...just east of port clinton...wild wings marina, i believe.....looking for a smaller boat so i can make a couple of trips a year to erie...........

 

[KaGee]

Re: omc 3.8L exhaust manifolds

My buddy dock's at Wild Wings. Actually it's a private dock at the condo's that a friend of his owns. I still trailer mine. It's about 10 miles west of Pt. Clinton.

 

[beanhauler]

Re: omc 3.8L exhaust manifolds

I would definetly replace them. I took the chance and one puked out before I even had 30 minutes on the new engine.

Look at my pics to see the OSCO replacement & mod I used.
OSCO is THE only set that will clear the front SELECTRIM rams. You could use the same thing for the 4.3, but you need to buy the shim kit to clear the valve covers.

Do the osco omc643 manifolds fit onto the 3.8l and definitely miss the selectrim rams?
I have tried the 4.3 manifold 984221 onto the 3.8 head and it def lines up
Not tried it with the head screwed to the block though.
Anyway can not buy new manies for the 4.3l only the osco 643
Any help or comments gratefully received

 

[Bondo]

Re: omc 3.8L exhaust manifolds

March 4th, 2007, 05:57 AM

Ayuh,... Welcome Aboard Beanhauler....

If you expect to get Answers to Your questions,...
Start a New Topic of your own.....

Hy-jacking a nearly Year old thread just don't cut it......
The archives are for learning, not posting onto...

Good Luck...

 

[beanhauler]

Re: omc 3.8L exhaust manifolds

Thanks boys


I take your point
Its just that i thought the thread was important if u get my drift
If i was lucky to get the guys involved who had the original discussion
i thought they might reply to me

I will follow your advice as i agree its a bit eggy
It must have been late

Thanks again