3.0L Exhaust Manifold

[Harritwo]

I just replaced the exhaust manifold on my 3.0L Mercruiser. I have the A03 Manifold. The old manifold had the end caps on it and Mercury informed me that the new ones do not as they have redesigned the manifold. The new manifold also did not have the divider between cylinders 2 & 3 as my old one did. With the block having seperate ports and the manifold not having seperate ports, will I experience any corrosion to the block in the exhaust passages that I need to worry about?

When I replaced the manifold, i also replaced the elbpw and inspected the shutters. The shutters were clean and free with no signs of corrosion but the manifold had started seeping on the outboard edge. When i got the manifold off, I replaced the elbow just because I was there.

Is there anything to worry about in relation to the corrosion? Is there any performance difference? Iwent back with Merc parts and to the best that I can tell, this is the original manifold and it is a 94. From reading on this forum, I understand that you normally do not get that kind of service life out of them. How often shall I expect to replace the manifold and elbow?

 

[fishrdan]

Re: 3.0L Exhaust Manifold

The new manifold also did not have the divider between cylinders 2 & 3 as my old one did.

Do you have any pics of the manifold they sold you? From your description, it almost sounds like the old 120HP manifold or 2.5L manifold with combined ports. It could be a new design, but having combined ports would hinder performance I'd think, maybe not?...