Corrosion inside exhaust manifold

U

utexasrick

Seaman Apprentice
Joined
Apr 25, 2011
Messages
46
So I'm putting my new rebuilt engine back together in the boat, 4.3L, 97 sea rayIMG_0104.jpgIMG_0105.jpg. I finally got the engine aligned and the outdrive installed. As I was reinstalling the exhaust manifolds I noticed that one port had some rust inside more than the other 2 ports. The manifolds are the old style one piece so I cant really pressure test it. I was able to hook up the water hose to it and let it flow water for a couple of minutes. All the ports looked dry and and no signs of water. The bolts were also pretty rusted. Only other thing I could think of would be maybe a leaking head gasket. Does this look normal or could there be a small crack? First pic is of the rusted port, next is the good one.
 
Bondo

Bondo

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Messages
70,513
Re: Corrosion inside exhaust manifold

utexasrick said:
So I'm putting my new rebuilt engine back together in the boat, 4.3L, 97 sea ray. I finally got the engine aligned and the outdrive installed. As I was reinstalling the exhaust manifolds I noticed that one port had some rust inside more than the other 2 ports. The manifolds are the old style one piece so I cant really pressure test it. I was able to hook up the water hose to it and let it flow water for a couple of minutes. All the ports looked dry and and no signs of water. The bolts were also pretty rusted. Only other thing I could think of would be maybe a leaking head gasket. Does this look normal or could there be a small crack? First pic is of the rusted port, next is the good one.
Click to expand...

Ayuh,.... This is a brand new motor,...

Scrap those things before ya gotta do this all over again....
 
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utexasrick

Seaman Apprentice
Joined
Apr 25, 2011
Messages
46
Re: Corrosion inside exhaust manifold

I was thinking about doing the newer 2 piece conversion but its more expensive than I though, almost the price of a new short block. I'm going to go ahead and try the acetone leak test see what happens then go from there. So three choices, do the conversion, buy a new single piece or reuse the current depending on the test results.
 
E

ENSIGN

Lieutenant Junior Grade
Joined
Jun 21, 2009
Messages
1,179
Re: Corrosion inside exhaust manifold

Take the manifolds to a machine shop and have them pressure tested
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Corrosion inside exhaust manifold

Take those mistakes called manifolds to the scrap yard. He might give you a few dollars for them, and that would be all they are worth. Merc discontinued them for a very good reason! As much as a new set of dry-joint manifolds and elbows will be, they will be cheaper then rebuilding that engine again.... If the engine is '97, then the manifolds will be that age too... The fact they hadn't killed the engine before now is a miracle.

Chris.....
 
Bondo

Bondo

Moderator
Staff member
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Messages
70,513
Re: Corrosion inside exhaust manifold

utexasrick said:
I was thinking about doing the newer 2 piece conversion but its more expensive than I though, almost the price of a new short block. I'm going to go ahead and try the acetone leak test see what happens then go from there. So three choices, do the conversion, buy a new single piece or reuse the current depending on the test results.
Click to expand...

Nope,... You have only 2 choices,.... as they don't sell those P'sOS anymore...

You can mess with what ya got,... Just Plan on replacin' yer motor again....
Or,...
Convert it to 2 piece manifolds, 'n risers...

As already said, repeatedly, they were a poor idea in the beginin', 'n ain't gotten any better with time...
 
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