Closed system cooling

[carolynrose]

I'm replacing my exhaust this spring with a new center rise aftermarket conversion kit. I currently have a log style exhaust on my OMC 260 (Chev 350) in a 1988 Bayliner. The engine has closed system cooling, raw water exhaust cooling.

Is there an advantage to including the exhaust manifold into the closed system? I assume that there would be a block off to the riser and some hose re-routing to do this with only the riser cooling with raw water.

Does anyone have a diagram or link to a diagram of this?

I'm considering the Osco conversion kit.

Thanks for your input.

 

[Bt Doctur]

Re: Closed system cooling

Including the manifolds depends on the capacity of the heat exchanger. Simple plumbing to add it.

 

[HT32BSX115]

Re: Closed system cooling

Is there an advantage to including the exhaust manifold into the closed system?

The biggest advantage is that the exhaust manifolds will probably last the life of the engine.

Your risers however, will still have raw water running thru them.

You will also need to completely block the coolant from getting into them and it will be under pressure.

This is where the "dry-joint" manifolds are REALLY nice..... there's NO CHANCE of a leaking riser gasket EVER allowing water back into the exhaust and damaging your engine.

Like BT said, you're going to be adding an additional heat load to the heat exchanger. If it's not large enough and capable of transferring the additional BTU's due to the exhaust manifolds, you may not be able to maintain coolant temp.


Cheers,


Rick

 

[carolynrose]

Re: Closed system cooling

Thanks guys, more to think about now. It's possible that replacing an exchanger to handle the increased temp may not offset the extra life of the manifolds. The engine currently runs right on the numbers and actually a little warmer if its run hard for extended distances. So it would need more capacity from a larger exchanger to include the manifolds.

 

[HT32BSX115]

Re: Closed system cooling

So it would need more capacity from a larger exchanger to include the manifolds.

Well.....it might need more capacity. It depends on what is there to begin with.

It's definitely worth it to have FULL closed cooling.... (you now have a HALF system) Depends on how long you're going to keep the boat....

The other obvious benefit is to not have to worry about "winterizing" (other than to drain the heat exchanger and other raw water components)

With a Half system, you're still draining the manifolds (and heat exchanger etc...)