Paul-WI wrote:... Does anyone have a good recommendation on an engine heater? The FBO here can install a plug in one that attaches to the oil sump and am thinking about that one. The dragon heater also sounds good but I don't envision leaving it outside overnight.
OK, I'm going to be a little long-winded here, so please forgive me. I bought my latest 170 in February 2004, along with a set of wheel skis (that I have not yet installed). First thing, I ordered insulated covers for the cowling, prop and spinner from
http://www.kennoncovers.com/ . The oil pan already had an electric heating pad on the bottom, but since there was nothing to heat the cylinders I ordered Reiff heater bands:
http://www.reiffpreheat.com . These install easily, and seem to work well.
Reiff recommended operating the heaters only when you anticipate flying, not full-time. I bought a 110v timer:
http://snipurl.com/jwt5 and set it to turn on the heater at midnight Thursdays and off at 5:00 PM on Sundays, because those are the days I fly. (I happened to have a kerosene heater thermostat :
http://snipurl.com/jwse , so I put that in the circuit to prevent the heaters from operating on warmer days, in case we had any.)
It was springtime before I got all this done, so the 2004-2005 winter season was my first chance to see how it all worked. My hangar has no heat or insulation whatsoever, and it isn't even tight. All bundled up with the Kennon covers, the heaters maintained the whole engine at about 70 degrees, even on cold days in Minnesota. That seemed pretty nice.
But after a while, I began to notice that the oil is a slightly different color than I'm used to, and the dipstick is permanently discolored where it's immersed in the oil. I don't know what that is, but it makes me uneasy every time I think about it in connection with that very vulnerable, expensive and scarce magnesium oil pan. I burn Philips XC 20/50 oil.
Maybe the application of heat is keeping moisture out of the engine and protecting it, or maybe something else is going on -- I really don't know. I know a flying club with Lyc powered 172s and 182s, where they leave the heaters on full-time under cowling covers, and have done so for at least 20 years without any adverse effect noted. But those planes get daily use whenever the weather isn't too bad.
I have friends who don't use any preheat other than their insulated, heated hangars. Their airplanes never know it's winter out there until the door opens and they're pushed out. Definitely the way to go if you can afford it!
Best Regards,
John
