Question about how inboard exhaust works...

[Mark42]

When running an inboard how does the cooling water get into the exhaust manifold? Ask because I see pictures of inboard V8 engines and the water pump/cooling water is attached to the exhaust maniford via hoses. Even if there is a one-way valve there to allow water out but prevent exhaust coming back in, I would think that the exhaust pressure at running speeds would be higher than the water pressure and there would be no circulation. <br /> <br />So I am wondering how that setup works.<br /><br />Thanks<br />Mark<br /><br />PS, I couldn't figure out what forum to post this in, so I chose this forum.

 

[Captn Dave]

Re: Question about how inboard exhaust works...

The water is run through a jacket that surrounds the exhaust manifold and is then dumped into the exhaust system downstream of the manifold. <br />Risers (an upward bend) in the exhaust manifold prevents water from back flowing into the exhaust.<br /><br />This is a typical set-up where the exhaust pipe exits near the water line. <br /><br />If the engine is raw water cooled, the engine, the manifolds and the risers are all cooled from outside water. If it's a closed system, the engine block and manifolds are cooled with an anti-freeze mix and this water is recirculated through a heat exchanger. Raw water is then run through the heat exchanger for cooling and then into the risers and out the exhaust.

 

[Mark42]

Re: Question about how inboard exhaust works...

Wave,<br />Thanks for sharing your knowledge!<br /><br />Mark