Fan Found

[honza]

This was in my air duct! Did anybody find a need to use a blower to cool engine in A25? The Beta manual suggests, that some kind of forced cooling should be present.

[nebulatech]

Wow, does the fan still work?

[honza]

It runs. But it is so low power, that it practically does not move any air

[motthediesel]

Well, you could try a warranty claim at Radio Shack, but your chances would not be good.

[Bob Noodat]

Very amusing, in a rather frightening way. Best take a careful look at anything else the DPO did!

[DesertAlbin736]

At first glance at the thread title I thought it meant a fan, as in an enthusiastic aficionado, of Albins. Those two vent outlets on the deck behind the aft cabin are for engine box ventilation. Isn't warm air at the engine intake a good thing? Seems the only heat problem might be with the alternator running too hot.

[honza]

A lot of mismatched threads - metric, imperial, fine coarse, NPT - forget BSP on the tank, but the fan is a masterpiece. So far.

[WillieC]

Replacement sinks-28TE

If I replaced my 28TE and it sank, that would be right up there with Fan Found.

[tribologist]

Been toying with the idea of adding a fan to push some more air out but the current ducts were designed to supply the engine through two ducts. Assume i would double the air flow. 1l engine at 2200 rpm is about 40 cfm. To make a difference one would have to pull 80 cfm through one of the duct and push 40 in the reverse direction through the other one. I have a few magnehelix gages that measures low pressure. I might do some measuring this summer while chasing DA around NE and Quebec. I been measuring about 70C/158F. (=1) at the intake at cruise speed. If i double the flow i could get that to more comfortable 45-50C

[Bob Noodat]

Been toying with the idea of adding a fan to push some more air out but the current ducts were designed to supply the engine through two ducts. Assume i would double the air flow. 1l engine at 2200 rpm is about 40 cfm. To make a difference one would have to pull 80 cfm through one of the duct and push 40 in the reverse direction through the other one. I have a few magnehelix gages that measures low pressure. I might do some measuring this summer while chasing DA around NE and Quebec. I been measuring about 70C/158F. (=1) at the intake at cruise speed. If i double the flow i could get that to more comfortable 45-50C

Why not just ducting from outside the engine cover directly to the intake? You would have the benefits of cooler air to the inlet manifold without any energy cost to get it there. Cooling the whole engine compartment is not really feasible without major energy expenditure. Have I mentioned the term "vicious cycle" yet?

[nebulatech]

Rube Goldberg frowns at you Bob

[tribologist]

Bob, that would make for a cold intake and a very hot generator.... The biggest improvement i did was to wrap the manifold. My engine has a regular manifold so it was heating engine compartment pretty good.

Ducting fresh air to the generator could make sense however. I don't think the engine itself care to much about intake air temp. Think about all the non inter-cooled turbo diesels used in boats.

[Bob Noodat]

Bob, that would make for a cold intake and a very hot generator.... The biggest improvement i did was to wrap the manifold. My engine has a regular manifold so it was heating engine compartment pretty good.

Ducting fresh air to the generator could make sense however. I don't think the engine itself care to much about intake air temp. Think about all the non inter-cooled turbo diesels used in boats.

The conventional view is that cooler air is denser than warmer air, which is hard to dispute, and therefore has a higher concentration of oxygen molecules to aid combustion efficiency. On the other hand a warmer engine is said to be more efficient than a cooler engine. I would also say that your generator (alternator, right?) is built to withstand high temperatures without any detrimental effect upon its longevity or performance. In any case you'll be making your generator work much harder to drive the high volume fan you would need in order to have any real effect of lowering your engine compartment temperature. So I don't know how we can resolve this!

[honza]

So, I just patch the hole in the duct and go slow. I think. Maybe, an outside/inside thermometer sensor under the hood would make sense for a while.

[Bob Noodat]

I was looking at the Beta installation manual and reading their ventilation recommendations. 440 m^3 per hour or 75cfm for 20hp. A computer-style plastic fan for this volume could indeed work! I am amazed. I am not saying this is what you should get, but just as an example of power draw, a fan of this capacity sold by Mouser (if I am reading this correctly)
https://www.mouser.com/Thermal-Manageme ... =1z0vu7eMm
is only 4.44W, very much less than I would have guessed.
So I was quite wrong about the size and power draw of a fan that can make a difference to engine compartment ventilation.

Oh, but another Mouser 75cfm fan says 1.68A, so 20W, but still not much. What would a ducted engine cooling fan built for these conditions draw?

What about this little fan? Pre 1990 F150 with EFI. Cheap at a wreckers I'd bet.
https://m.youtube.com/watch?v=RnYy2cTSgw8