What to look for when inspecting manifolds/ risers?

[LegacyT]

Pulled my engine and wondering what to look for to decide whether to reuse/replace my exhaust manifolds?

 

[true blue]

Re: What to look for when inspecting manifolds/ risers?

You are looking for excessive rust, blockages, leaks, damage. You do not want leakages between passages or anything looking like its restricted by rust, foreign objects etc. To re-install, surfaces must be solid, flat. New gaskets.

 

[74bayliner]

Re: What to look for when inspecting manifolds/ risers?

Take it in to get Hot Tanked at a Machine shop. It will clean all the rust off and clean it up for you. It costs 50 bucks or so. When mine was done it was discovered that there was huge rust hole on the inside that i did not see when i inspected it myself.

 

[LegacyT]

Re: What to look for when inspecting manifolds/ risers?

My manifolds held the anitfreeze all winter well. But quite abit of rust chunks fell out of the water passages and one of the riser bolts snapped off into the manifold due to corrosion... Out of curiousity anybody have experience with barr marine manifolds? I heard to stay away from glm products.

 

[Don S]

Re: What to look for when inspecting manifolds/ risers?

Take it in to get Hot Tanked at a Machine shop. It will clean all the rust off and clean it up for you.

NOT a good idea. That rust comes from the inside of the manifolds, when they plug up with rust, they are telling you that the insides of the manifolds and risers are really thin from rust, kind of an early warning system. You clean the rust off, the next warning is water in your cylinders and possible engine death.

 

[74bayliner]

Re: What to look for when inspecting manifolds/ risers?

Oh ok i see what you mean Don.
Yeah i only got mine hot tanked because i thought it was fine and just wanted to clean up the outside.
First hint should have been when i saw this under the thermostat housing:

I have since then purchased new manifold and new risers

To answer your question Legacy. I purchased the BARR ones for my boat and they come with 2 year manufacturing warranty and the look nice, although im not super happy about the black paint job them have on it. a few flakes from the brand new one.. nothing major .
Cost me a little over 600 bucks total for mine. but worth it for me at least.

 

[LegacyT]

Re: What to look for when inspecting manifolds/ risers?

Do they come with new pre-installed expansion plugs?

 

[74bayliner]

Re: What to look for when inspecting manifolds/ risers?

I would have to come home to double check, but i believe so.
Yes they do. Now that i think about it, if they came without them i would have frieked and bought some right away.

PM headed your way

 

[Don S]

Re: What to look for when inspecting manifolds/ risers?

You guys are talking about two completely different engines. A Volvo 4 cyl from 74, and a Chevy V8 from 89.

Typically, exhaust manifolds and risers come with core plugs installed, the holes are there to hold the core during the casting process, and a place to get the sand core material out of the casting. Then plugs are installed.

 

[74bayliner]

Re: What to look for when inspecting manifolds/ risers?

Ha! man don. see u learn something new every day i never really knew why the holes where there but it makes sense now. Please dont ever retire from Iboats!