VOLVO B20 atomotive converted to marine, exhaust manifold smoking

[johnmorgan]

My first boat has a automotive b20 volvo with a 270 leg. Why would there be smoke coming from the top of the exhaust manifold, just where it attaches to the block right in the middle. where the engine liftout hole thing is. also because this boat has an automotive engine there is some kind of hx hooked up that has an expantion tank and is cooled with raw water that is pumped by a pump that is custom mounted on the motor could my exhaust manifold not be getting cooled enough. thanks

 

[erikgreen]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

Pretty easily, yes.

Automotive engines can be converted to marine use, but it's more complicated than just swapping it in. Who did the swap? It doesn't look like they put in a marine manifold, which I think is a fire hazard. The cooling system you mention would be optional with a real marine engine, but may be necessary with your auto engine.

Do you happen to know if the B20 engine was ever sold in a marine version by volvo?

Keep a fire extinguisher handy, I'm not sure your engine is currently safe.

Erik

 

[PiratePast40]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

I went back and thought about the closed cooling vs raw water cooling systems and believe my comments about temps on the marine version (AQ130 series) won't necessarily apply to your closed cooling system. But I still believe you need to determine if it's a gasket leak, cooling system leak, burning hose, or actually overheated engine. The fact that your gauge didn't show high temp is a good indication but you should really find a way to actually check contact temps on the engine.

From what I can tell, you do have the marine exhaust manifold but a picture from that side will help.

 

[johnmorgan]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

sorry for the wait guys I found out that the exhaust manifold and the oil cooler were hooked up to the fresh water cooling system. so they were not getting cooled enough at high rpm now I re routed the cooling so the raw water goes to the oil cooler and then through the exhaust manifold. my next question is, will the water be cool enough to cool my heat exchanger after it has went through the exhaust manifold? If not how do the closed water systems on other boats work, how should I run my hoses i only have about seven different hoses lol good times. my best time spent on my boat so far has been, figuring out which way the water flows.

 

[Don S]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

Typically, the water comes in to the raw water pump first, then to the oil cooler, then the heat exchanger, then to the exhaust manifold.

 

[johnmorgan]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

I really have to show your guys some pictures, I have a manual for a aq130, my motor is only the same block. the manual has a lot of useful info but not much about the cooling systems thanks every one for the help. If my hx is cooling the motor enough will it be a big deal, because after i ran the new hoses even though the water is going through the exhaust manifold first, the motor seems to be running at a good temp, even at four thousand rpm. It will be really hard for me to run water through the oil cooler, then the hx, and then the exhaust manifold just because of the way the person who sold me this boat set up the raw water pump. If you guys think i should change it though I will change it because I really only know what i have read on here. I am mechanical inclined but not a mechanic thank you all for the help again.

 

[PiratePast40]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

I think you have to go on the assumption that it did actually work at one time. If that's the case, then you'll need to troubleshoot each component of the system. Does the closed cooling portion of the system actually contain enough water and does it stay full? Is there flow through the closed cooling portion? Do you have sufficient flow through the raw water portion? What about the common bad actor for this drive - the water neck fitting on the outdrive? Those corrode and allow air into the suction side and don't allow water to flow. It's a matter of process of elimination, just that the rest of us aren't sure of the specifics of the flow paths on this system.

 

[johnmorgan]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

seems to run at a really good temp now that the exhaust manifold is cooled by raw water. I can put my hand on the exhaust manifold after it was running four thousand rpm for ten minutes, and the motor is really cool to never going over a quarter of the gauge. good flow after I flushed some rust out to. I have really good flow coming into the raw water pump

 

[sqbtr]

Re: VOLVO B20 atomotive converted to marine, exhaust manifold smoking

You can put a clear hose between the transom and the water pump and visually verify clear water flow.