Idea: Engine Compartment Cooling Using Marine Bilge Exhaust Fan

[Josey1972]

Its possible that I am overthinking this thing but I am trying to find a way to get heat out of my engine compartment. I'm not experiencing any issues at this point. My radiator is new and the system is working fine. But in an effort to make things harder I thought Id like to figure out a different way to get heat out of the engine area.

My first thought was to just do the hood louver gig. But finding a puddle of water on your breather box or you decide to pound a water hole and get mud all over the place,,,, I just decided I didn't like the idea very much.

I thought about a side vent in one of the fenders. Hmmmm. Not very efficient for the heat to go out the side when it really needs to go out higher for more efficiency. Hmmmm again.

Then I thought about the fan mods that everyone has done. OK, I suppose that works but basically you are cooling with air movement only. You're just forcing hot air from the same area against a hot area...

So, I recall as a kid, when I worked on boats and the vents they used to exhaust fumes out of the engine rooms. Hmmmmmmm I said. So, they make nice little inline exhaust fans in a 3" and 4". I'd love to see a 2" but couldn't seem to find one.

So, what do people think of this? It would be super efficient. It would suck hot air out of the engine compartment forcing the truck to take in cooler outside air. Its the same theory as the exhaust fan in your dunny. The fan pulls the rosy air out and pulls in fresher air from the rest of the house.

Any thoughts? Or has anyone attempted this?

 

[half k cruiser]

Ok, I'll play.

1) where will you mount the fan ? In the hood ?
2) can it overcome the air flowing over the surface at speed ?

Essentially your wanting to create an area of low pressure under the hood. However, you would need an area of lower pressure to exhaust it to correct ?

 

[ton504]

Jet-hot or any other thermal coating on the exhaust manifold might help keep the temps down.

 

[Josey1972]

Ok, I'll play.

1) where will you mount the fan ? In the hood ?
2) can it overcome the air flowing over the surface at speed ?

Essentially your wanting to create an area of low pressure under the hood. However, you would need an area of lower pressure to exhaust it to correct ?

I haven't gotten far enoug into it to think about the location. The one I looked at moved 130 CFM's which is more than your standard bath fan. I was thinking of finding a vent out the side of the fender. The bummer is that they dont make them smaller than 3" I suppose I could choke it down. I would think that 130CFMs in that small space should litterally suck outside are in. I'm no HVAC guru but it seems that would be the case.

 

[Josey1972]

Jet-hot or any other thermal coating on the exhaust manifold might help keep the temps down.

I'm planning to that anyways. I come with projects like this in my own little Rub Goldberg contest.

 

[Josey1972]

I haven't gotten far enoug into it to think about the location. The one I looked at moved 130 CFM's which is more than your standard bath fan. I was thinking of finding a vent out the side of the fender. The bummer is that they dont make them smaller than 3" I suppose I could choke it down. I would think that 130CFMs in that small space should litterally suck outside are in. I'm no HVAC guru but it seems that would be the case.

To add to that I thought about just dumping out the bottom of the engine compartment.

 

[ton504]

To add to that I thought about just dumping out the bottom of the engine compartment.

They're not going to pull out any air unless you have the engine compartment sealed off like the boats. And if you do happen to go ahead and attempt that, the radiator is probably pulling way more cfms than those exhaust fans and your new fans will be a choking point.

Thermal coating on exhaust manifold and call it a day.

 

[izzymonkey]

Like ton504 said. In the aviation world pilots will seal their engine compartments to aleviate stagnant air and increase air cooling flow over the heads for more efficiency.Your best bet would be electric push pull fans on a thermo sensor.

 

[Jason hansen]

There is a fan in front of your engine, put 30,000 cst Lucas silicon diff fluid in the fan clutch so it will work better. Sorry if this is not the advice you are looking for.

 

[SmokingRocks]

your radiator fan will pump between 1200 -1800 CFM (RPM dependant). A 130 CFM fan will do nothing for you.

I've also thought about engine compartment cooling and have always returned to idle because when you think about it the engine doesn't really care about how 'warm' the compartment is, its water cooled.

And the only way to bring temps down would be to put some major cooling fans in big louvers on the hood. Like the Lincoln mk iv fans that pull 2,000 cfm. and you would probably need two at full chat to make much of an impact. Then think about the fact that those lincoln fans draw about 35-50 amps each an your alternator only puts out 80 at peak output..

Yea thats where I stopped thinking about it and spent my money on header wrap.

 

[Josey1972]

Thanks for the input. Fellas. Wrap is ordered.

 

[NLXTACY]

I've been down this rabbit hole.

Header wrap= rusty headers
Ceramic coating exhaust Manifolds and heat shields did a lot to reduce underhood temps.

 

[RFB]

I've been down this rabbit hole.

Header wrap= rusty headers
Ceramic coating exhaust Manifolds and heat shields did a lot to reduce underhood temps.

Can cerm coat be appiled on your own or does it need to be done by a pro??

 

[Josey1972]

I've been down this rabbit hole.

Header wrap= rusty headers
Ceramic coating exhaust Manifolds and heat shields did a lot to reduce underhood temps.

I found that they have a silicone product that fills the wrap and seals it. I live in the Midwest rust is a big concern for me.

 

[RFB]

I found that they have a silicone product that fills the wrap and seals it. I live in the Midwest rust is a big concern for me.

Ditto, I live across the street from the Atlantic So. it gets rusty doing nothing

 

[Kaninja]

I think just hood vents are the best bet. You have the 1000+ CFM from the stock fan (assuming sufficiently heavy fluid in clutch) and the negative pressure created just above the hood while vehicle is in motion. This will evacuate a lot of the hot air under the hood. It won't do boo for bringing down coolant temps but will help prolong the life of underhood rubbers, accessories, and such.

Things like EPDM rubber lose half it's elastic property life every 10°F increment past 160°F.

 

[Josey1972]

If I do the hood vents I'll have to fabricate a box to direct water out. Wheeling in this region involves mud etc. and it rains here quite a bit. So that may be how it ends up. As it goes now I have no issues but with the blacked out hood and going to cruise moab next year I want to be beyond ready. So I guess back to the drawing board.

 

[benjrblant]

@treerootCO had his exhaust headers blasted and sealed with a cerakote heat insulator. Last I asked, he said they were doing a very good job of keeping temps down. This is probably the best rust protection you can get for a cast iron component that sees extreme heat and is prone to rust.

 

[Josey1972]

Cerakote? Interesting. I may consider that. High temp paint and then wrap it? Is that what your saying?

 

[benjrblant]

Cerakote makes a high-temp coating specifically for automotive and engine applications. It seems to work exceptionally well at keeping heat inside the header, plus its application process makes it inherently very rust resistant.
Cerakote Coatings

I'd be inclined to try cerakote on the header first. If not satisfied, I'd then consider a wrap knowing that the cerakote would protect the header from further rust and decay. Downside to cerakote is that you'd have to pull the header and possibly Y-pipe to be dropped off at a shop that can apply it.