Internal engine pre-heater--opinions?

Domenick

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Domenick
 
Not sure what you’re after here but this is similar to the oil heaters in the Tanis kits. The main difference is that this is 250 watts instead of 50 like the typical Tanis oil heater is.
 
Seems like a lot of energy (250 W) to put into oil through such a small heat transfer area.

The Reiff hot strips I have on my airplanes are two 100 watt heat strips mounted to each sump. The sump gets hot then transfers the heat to the oil, so there are no extremely hot spots.
 
It is an oil pre-heater. Helpful but from what I heard not ideal as you want the entire engine to pre-heat. I have an oil pre-heater installed but on really cold days, I also plug in a very little space heater, put it in the cowl, wrap up the cowl with a blanket and heat the engine itself overnight. Makes starting much easier and probably is easier on the engine.
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I had a Tannis on my IO-540 (182-S) that included the cylinder heaters. When I had a JPI 830 installed the drilled bosses where the heater elements were attached had to be used for the cylinder head probes so that left me with just the oil pan warmer. Recently I had to make a flight with the temperatures in the mid 30's F. The airplane was in a large non-insulated, non-heated hangar and I left my Tannis plugged in overnight. I closed the cowl flaps and put in the cowl plugs. The next morning the oil was definitely warm to the touch...much warmer than I expected. Also, the #1 and 2 cylinders were warm to the touch but colder than the oil for certain. I would guess, based on temp immediately after starting, the oil temperature was in the mid 70's F. I was concerned that eliminating the cylinder elements would be an issue but now I don't think so. If I was in a much colder climate or outside I definitely would desire keeping the cylinder heating function.
 
I was one of the beta testers for the AntiSplat heater. It works great and I use it now. It does heat the entire engine from the bottom. I use a reflective blanket and sleeping bag over the cowl, plug the cooling exit around the exhaust, and cowl plugs. I can heat the engine oil to 90 degrees when it is at 10 degrees in the hangar overnight.

I did wonder about heating from the bottom only so if I want to heat faster, I have a 5" ceramic heater with a reducer duct into my plenum air intake. It is 500 watts. With both going I can heat the engine to 90 degrees in about 5 hours at 10 degrees. Either will keep the engine hot.

I have a dehydrator that I run 24-7 when I am not flying. I plug the exhaust pipes with rubber toilet plugs with long red straps on them connected to my cowl plugs to make sure I dont forget!

I am satisfied with my setup.
 
That type of heater can and will turn the oil to coke on the heating probe. not what you want for your oil.
I also think it is designed to be used while the oil is moving, otherwise it will burn the oil.
 
That type of heater can and will turn the oil to coke on the heating probe. not what you want for your oil.
I also think it is designed to be used while the oil is moving, otherwise it will burn the oil.
I have used it for 2 years and send my oil to Blackstone for testing every 25-35 hours with no issues. I take it out in the summer at an oil change and havent seen any type of burning or coking up on the unit. If anyone has, I would like to know. Maybe if it was left on all the time it could cause issues but I only leave it on to warm up before a flight.
 
That heater won’t burn 6+ quarts of oil sitting in 250# of chilled steel and aluminum. I wouldn’t use one on its own any more than I’d use any sump heater without a top heat addition.
 
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That heater won’t burn 6+ quarts of oil sitting in 250# of chilled steel and aluminumI. I wouldn’t use one on its own any more than I’d use any sump heater without a top heat addition.
Yeah, but you live in Alaska. Living in Georgia, where my hangar temps (at least on flying days) are probably no lower than 15-20F on the worst days, a sump heater does a great job of bringing the entire engine up to ~100F after a night's use.
 
Looks OK and installation is certainly easy. It's not grounded so could potentially be a shock hazard. Also something with a thermostat may be desirable...
 
Yeah, but you live in Alaska. Living in Georgia, where my hangar temps (at least on flying days) are probably no lower than 15-20F on the worst days, a sump heater does a great job of bringing the entire engine up to ~100F after a night's use.
Bottom heat promotes corrosion. Geography has nothing to do with that.
 
Bottom heat promotes corrosion. Geography has nothing to do with that.
It's a sample of one, but 17 years of using bottom heat only, engine past TBO, no corrosion. I left the heat on most of the time because I was flying the airplane regularly. Bonanza with IO-550, an oil pan pad on each side (no clearance below) in Michigan, Minnesota and Wisconsin. But geography has nothing to do with that.
 
Try that on a Lycoming. Continentals aren’t immune but they do have better resistance to cam cancer. In any case, it’s a poor way to preheat cylinders. The colder the ambient temps the more that’s true. Air cooled cylinders are designed to be cooled by outside air.

At any rate, y’all should do what you think is best for your engines. Happy flying.
 
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I just ferried an Arrow 800 miles in sub-freezing temps, including an overnight stop. I used a "twin hornet" engine heater each time. The engine started easier than a summer day each time.
 
I had a Tannis on my IO-540 (182-S) that included the cylinder heaters. When I had a JPI 830 installed the drilled bosses where the heater elements were attached had to be used for the cylinder head probes so that left me with just the oil pan warmer. Recently I had to make a flight with the temperatures in the mid 30's F. The airplane was in a large non-insulated, non-heated hangar and I left my Tannis plugged in overnight. I closed the cowl flaps and put in the cowl plugs. The next morning the oil was definitely warm to the touch...much warmer than I expected. Also, the #1 and 2 cylinders were warm to the touch but colder than the oil for certain. I would guess, based on temp immediately after starting, the oil temperature was in the mid 70's F. I was concerned that eliminating the cylinder elements would be an issue but now I don't think so. If I was in a much colder climate or outside I definitely would desire keeping the cylinder heating function.
I have started doing the same thing and keep my cowl covered and the air inlets plugged With an old moving pad. When I put the sump heater on overnight via my cell phone switch, I can come out in the morning and the engine bay is warm and the cylinders warm to the touch. Metal has good heat transfer characteristics. Works very well down to 20 degs ambient, hangar at about 28 degs. Colder than 20 degs ambient and it is to cold for me to want to fly.
 
Try that on a Lycoming. Continentals aren’t immune but they do have better resistance to cam cancer. In any case, it’s a poor way to preheat cylinders. The colder the ambient temps the more that’s true. Air cooled cylinders are designed to be cooled by outside air.

At any rate, y’all should do what you think is best for your engines. Happy flying.
I agree with what you are saying for a Lycoming since the cam is not bathed in oil like the Continental. But if you only heat (sump heater only here) when you are going flying, then if you fly for an hour on more with oil temps at 170-180 degs, the heating of the oil gets rid of the moisture in it. BTW- what do you do after you fly to get the moisture out of the engine as the engine and oil cool down in 20-30 degs ambient temps? FWIW…. This topic comes up every winter.
 
A Continental’s cam isn’t submerged in oil, if that’s what you’re implying. It does sit low so isn’t in the condensation cavity like a Lycoming but Continental cams fail from corrosion, too, just not at the rate of Lycomings.

I built engine dehydrators for my planes now that they live indoors. Prior to that I enjoyed knowing that any moisture inside the engines would be frozen when not being preheated. It’s -15° at my house but 50° in the hangar. Heat promotes rust, so I keep engine internal RH in single digits.
 
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