Engine dehumidifier

There's a bunch of products out there, but none good enough that I'd rather buy them than make my own.
 
I bought a Black Max last year and it appears to be well built and does remove water from my engine. It has an air conditioner and heater circuit and doesn't have any desiccant that would need to be changed routinely. Very hands-off, and it costs about the same as a quality desiccant unit. But flyingcheesehead is right - if you are handy you can build one. A friend of mine built a nice desiccant unit out of a 50 cal ammo box and bought an old oven (keeps it in his hangar) at the Salvation Army to dry and reuse the desiccant, both for a fraction of what these things cost.
 
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JohnAJohnson said:
I bought a Black Max last year and it appears to be well built and does remove water from my engine. It has an air conditioner and heater circuit and doesn't have any desiccant that would need to be changed routinely. Very hands-off, and it costs about the same as a quality desiccant unit. But flyingcheesehead is right - if you are handy you can build one. A friend of mine built a nice desiccant unit out of a 50 cal ammo box and bought an old oven (keeps it in his hangar) at the Salvation Army to dry and reuse the desiccant, both for a fraction of what these things cost.
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Y'know... There's only one thing wrong with the Black Max: My IO-550-G's breather tube attaches to the top of the oil filler tube, so this wouldn't pass any air through the crankcase. I'd be relying on diffusion through a tiny hole (about 1/4" diameter).

But, coupled with one piece of what I was going to do, it could work great. My plan was to get a second oil dipstick, remove the stick part, and replace it with a tube of the correct size and length to make it through the hole from the filler tube into the engine with room to spare. Then, I could actually pump the dry air directly into the crankcase and it would exhaust through the breather. Keeping the engine heater on in the colder months should allow the air to exit the breather without getting so cold that the moisture condenses in the breather (and potentially even ices it up).

Considering how much time and energy it would take me to actually execute my planned setup, which has resulted in me not even starting on it, this Black Max thing looks all right if I can just get the air into the right part of the engine!
 
Valid point. The only negative I have to say about the Black Max is the way it connects. In my case (Lycoming), I slide a tube up the oil breather, past the ice hole. The tube is stiff 1/4" plastic, with foam rubber glued around it to ensure a tight seal. In time, that foam rubber wears off, and the cure is to buy another one for $10 from the manufacturer. I looked for a replacement dip stick on ebay etc. and was going to drill it and use that instead of the oil breather tube, but lost my motivation. I'm thinking a rubber cork (drilled with the 1/4" tube going through it), inserted into the oil filler would do just as well.
 
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