Buildup in exhaust manifold

[Captsteve53]

Bob, Forgot to say your picture actually looks like a riser (not a manifold) also any spraying water is done at the exhaust riser (not inside or near the manifold?

Cheers Steve

[Uncle Bob]

Originally Posted by Captsteve53

Bob, Forgot to say your picture actually looks like a riser (not a manifold) also any spraying water is done at the exhaust riser (not inside or near the manifold?

Cheers Steve

Hi, I am not the one asking the original question, I merely have a friend who is suffering a similar problem with a corroded manifold and thought the idea of a more robust version sounded good.
Cheers.

[hd002e]

I hope I did not cause a confusion by using the incorrect name for my part. According to VOLVO PENTA, it is called the exhaust elbow.

I ended up ordering a stainless steel replacement from HDI Marine, located in Washington state.

Now that I have seen the inside of the elbow, I realize this must have caused a lot of constriction for the raw water system. This probably explains why I had the heat exchanger leak last year!!

[Compass790]

Originally Posted by Uncle Bob

Steve, all I can see there is stainless exhaust elbows, not a manifold in sight as far as I can see.

Yep I apologize, assumed it was exhaust elbow as didn't read properly. Haven't attempted to make an exhaust manifold out of ss. & never seen one. Thanks Unc. Bob for pointing it out.

[Compass790]

Originally Posted by Compass790

Yep I apologize, assumed it was exhaust elbow as didn't read properly. Haven't attempted to make an exhaust manifold out of ss. & never seen one. Thanks Unc. Bob for pointing it out.

Woops in fact it was an exhaust elbow! so my original post still stands. Think you have done the right thing buying ss exhaust elbow but still have to check for carbon buildup periodically.

[JPA Cate]

CapnSteve53,

Through the passages in the head that clog up with salt, yes. Hence removing the zincs.

If he has a heat exchanger that is soldered, and clogged, that would need to go to a radiator shop. But that hose, that the OP posted the picture of, sure looks like it has salt crystals in it.

Ann

[AlanR]

If you use the wrong word, you convey the wrong idea. The originsl post showed a picture of the water injection bend, which sits between the manifold and the exhaust hose, where the water is injected into the exhaust gasses to cool them. We are discussing removing salt, not carbon.

Manifold means many, and on this context, it is where many (3, 4 or 6 usually) exhausts from each cylinder are joined into one exhaust pipe.

Hope this clarifes things.

[hd002e]

Originally Posted by AlanR

If you use the wrong word, you convey the wrong idea. The originsl post showed a picture of the water injection bend, which sits between the manifold and the exhaust hose, where the water is injected into the exhaust gasses to cool them. We are discussing removing salt, not carbon.



Manifold means many, and on this context, it is where many (3, 4 or 6 usually) exhausts from each cylinder are joined into one exhaust pipe.



Hope this clarifes things.

Right, it is a two cylinder engine (VOLVO PENTA 2002) and the part I am looking at is supposed to inject water into the axhaust but I fear it is not doing its job well as the exhaust water that comes off the back of the boat is pretty cool and the engine over heats.

[jamhass]

Originally Posted by Captsteve53

Would like to make a comment here, The Electrolysis system as above is based on Galvanic Corrosion and stray electrical current corrosion and there's one big hole in that theory (and eventually in your manifold leaving the Carbon in place and here's why:

1) “Carbon” comes from the Latin word “carbo,” which in English means “charcoal.” It is an element represented by the letter “C” and bearing the atomic number 6 on the periodic table.

2)Here's the main point:Carbon is a solid "non-metal" element

3) Since Carbon is a NON -METAL ELEMENT the so called Electrolysis will corrode the iron base (Metallic) but not corrode the Carbon, after corroding the iron base the Carbon may fall away leaving very suspect cavities behind?

Cheers Steve

Gotta disagree, in practice at least.

This method worked flawlessly on my exhaust elbow -- twice. Elbow came out very clean, didn't affect the (very expensive) green Volvo paint, but left the interior very nice. Left the unit working overnight. Takes more time to write about it than set it up.

I suspect that while your theory may be correct, the crud isn't just carbon, but has a lot of other stuff in it that IS subject to this method, just as rust is.