I Need Exhaust Help

[Captndan714]

Last weekend I noticed I had a crack in what I think is the muffler/ exhaust elbow after my engine compartment filled with exhaust. I'm having trouble finding answers as to what exactly the piece is and how I can replace it since it's an old Volvo engine and I can't find parts for it anymore. Does anyone know how I can replace/ rebuild this system properly? Here are pics of the part. The crack is in the finger piece where the hose attaches and runs to the heat exchanger.

[sdowney717]

it looks like it has been welded before.
A type of waterlift muffler?

[DeepFrz]

Looks sort of like an injection elbow/muffler rube goldberg affair.

[sdowney717]

the second picture your looking down onto the muffler top.
the exhaust goes in where it broke and it has a water injection port.
the exhaust water steam then comes out on the rubber hose part.

IF the muffler is in good shape or bronze then I would take it off and have it rewelded.
You might consider getting a bronze or SS pipe fitting and welding attaching that fitting to the muffler. Then have a threaded pipe setup back to the motor exhaust output off the manifold.

A lot depends on what condition the waterlift muffler is in.

SOME of these were plasticized rotospun inside to prevent rust, such as the one on my onan generator.

[sdowney717]

I have one of these on the generator and it has been fine for 40 years.
Wet-Lift Muffler Issue on Silver Fox

these mufflers have a plastic type liner, but they can rust on the outside. Or if someone burns the fitting out of the top with a torch, not a good idea.

If you replace your setup, you will need a water injection setup before the muffler. On yours, exhaust is going in and water right next to that. So the piping you put together, create a water injection manifold before it enters the new waterlift muffler.
You can do this using a tee and a copper tube that goes down into the top of the tee so the water stream enters the exhaust stream and make it so water cant get back into the engine..

[John A]

Everything shown may be re-fabricated. Check with a boatyard for references for a skilled welder. I'd suggest replaceing the muffler at the sametime.

[Captndan714]

Thanks for the help. It would be nice to find a similar part where the exhaust and water enter the muffler together so that I could just swap them out rather than trying to refabricate the whole system. I would have to take a closer look, but I have a feeling the muffler is a total loss as the previous owner did not take proper care of the engine and the entire thing seems to be rusted through and corroded. This is my first year owning the boat, so I'm trying to gain knowledge about engine maintenance and repair. In order to refabricate, as I understand it, I would need a mixing elbow before the muffler. But how do I ensure that the water can not wash back into the exhaust manifold? Do I need to install a riser before the mixing elbow? And where do each of these pieces need to be installed in relation to the water line?

[S/V_Surya]

Looks similar to my set up on my old volvo two banger md6b. Replace pipe coming off engine, looks like four bolts, with fabricated piece with water injection welded on. Then replace muffler with plastic aqua lift type. Should last for years. Cheaper than muffler fabrication.

[motion30]

I believe to can by the correct size fb muffler then add a bronze T to the in side and inject the water there Measure in inlet and out sizes that all you should need , not rocket science

[Captndan714]

Ok new question. Do I need to install a riser out of the exhaust manifold before the mixing elbow to prevent backwash into the engine? And two, is there a limit to the distance below the water line that I can install the muffler? I saw photos of an installation yesterday where the muffler was installed at the bottom of the bilge. This would obviously increase the distance the backwash would have to travel uphill to reach the exhaust manifold, but is there a disadvantage to mounting the muffler so far below the waterline?

[S/V_Surya]

Way back when my problem was water getting into the engine that is why I went with aqua lift that prevents that. My problem turned out to be a faulty anti-syphon valve. The volvo dealer sold me a stainless steel muffler for $200.00 this was back in 1980. The acid in the diesel ate out the welds in about a year. Replaced with plastic aqua lift muffler for about $10.00. Worked fine unit my cousin failed to open through hull water intake valve. Melted a little bit. My muffler was about level with centerline of engine.