need better venting

floater212

Petty Officer 2nd Class
Joined
Nov 27, 2013
Messages
146
I am looking into a better engine compartment venting for more air flow so I will install another fan for just that, high up drawing just hot air out, bilge fan is still going to be there for start ups because of low air draw. now I've heard of adding a thermostat to turn it on when it gets too hot. I also read that they use a klixon thermostat, they have way too many so, which one do I get? and what temp to turn extra fan on? or am I just overkilling the project?:noidea:
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: need better venting

Yes, You are over killing the issue. :D

The Bilge fan removes fumes from under the engine and pulls fresh air in from the top. (~100cfm)
The Running engine pulls in more air than any fan you would likely install.
A 2 liter engine uses over 175 cfm at 5000 rpm.

But if you insist....
If you are looking to have the fan come on after an engine shutdown when the temperature peaks from the hot motor, A T-Stat in the 120 to 140 degree range would be about right. Any lower and it would keep coming on every Sunny day in Illinois.
 

floater212

Petty Officer 2nd Class
Joined
Nov 27, 2013
Messages
146
Re: need better venting

so which thermostat from what store do I get? I do have a 2005 21' Rinker ski boat with a 300hp. mpi, with all the pulling it does it gets quite hot in the engine compartment.
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Re: need better venting

Spend your money on gas. Under the doghouse is cooler than under the hood of your car. IMHO.
 

floater212

Petty Officer 2nd Class
Joined
Nov 27, 2013
Messages
146
Re: need better venting

so then what is the usual temp for an engine compartment? what temp should the blower activate at? which thermostat brand and number should I look at? cooler is always better than hotter. imho
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: need better venting

If you insist.... :eek:hwell:

Your engine typically has a 160 degree thermostat in it so the engine compartment being power ventilated by the engine sucking ~100CFM is going to be cooler than 160.

The boat sitting stopped in the sun might heat into the 120 Deg range.
I would choose a thermostat that came ON at 140 deg and shut OFF at 120.
All these temperatures are going to be very uncomfortably hot to your hands or body.

Compare this to the millions of cars driving over hot asphault all summer with engines containg T-Stats in the 180 to 210 degree range, and you can appreciate that your engine compartment is already relatively very cool.

Adjustabe Snap Action Thermostats are availble from many sources.

But, as has been suggested.... :)
Spend your money on gas. Under the doghouse is cooler than under the hood of your car. IMHO.
 
Last edited:

floater212

Petty Officer 2nd Class
Joined
Nov 27, 2013
Messages
146
Re: need better venting

thanks for the info. definitely overkill, but had to check it out anyway!
 
Top