Engine compartment ventilation?

[Petar]

Hi,

does anyone have an extraction fan fitted in engine compartment to reduce the heat generated by diesel inboard engine running? I guess the best spot to fit it would be on the top where all hot air tends to accumulate.

Any thoughts?

[MARC2012]

Have regular bilge blower,mounted on bottom.It works fine seems to keep cooler.Really loud you won't forget to turn it off.marc

[captbillc]

i haven't seen the need for a fan. a diesel's air intake is not restricted and they run with a lot of excess air, which keeps my engine compartment from getting too hot. when i worked at cummins, before i retired we checked for a leaking valve by removing the manifold & running the engine at idle speed.

[sailingdog]

I don't, but it isn't a bad idea to have a fan that exhausts the engine compartment. The cooler the engine compartment, the happier your alternator and such will be, and the longer they will generally last.

I'd go with the bilge blower rather than a smaller extraction fan, as the bilge blower is ignition protected and designed for this specific use.

Originally Posted by Petar

Hi,

does anyone have an extraction fan fitted in engine compartment to reduce the heat generated by diesel inboard engine running? I guess the best spot to fit it would be on the top where all hot air tends to accumulate.

Any thoughts?

[wwilson]

Originally Posted by Petar

...does anyone have an extraction fan fitted in engine compartment to reduce the heat generated by diesel inboard engine running

Agree with MARC2012 - Our bilge fan is effective in cooling the engine compartment (and fume extraction for which it is intended) but it is not a sound that you can live with for very long. Sounds a bit like the APU of an Airbus 320!

[Faster]

A friend's Bene 36.7 has an engine box blower/fan that runs when the engine runs... keeps the heat down and tends to remove engine smell too.. I'm considering adding same to our boat.
As mentioned some time back, an off-delay function on such a fan would be a nice feature.

[Architeuthis]

Yep both a Air supply and powered exhaust. Air temps in there get above 60c with the fan off, and below 40c with the fan on.

I think you want to look at air flow and try to control it such that fresh air is directed at engine intake (cooler air is more dense), Alternator (for cooling) and lastly across the exhaust or hot side of engine and is then exhausted out.

I have a speed control on mine as wide open moves alot of air, much more than is needed many times, and to keep the noise down. In the summer I leave the fan on for quite a long time after shutting the engine down as that big block of liquid and steel pumps out lots of heat long after it has been shut down.