When I was renting airplanes, I didn't give two rips about starting an engine in sub-freezing temperatures. It wasn't my engine.
Now that I'm flying my own airplane, and now that I've had to relocate to an unheated hangar, I care. A lot.
So other than a circuit around the pattern prior to moving the airplane from the old hangar to the new one, I haven't flown much, and I don't want to start the engine until it's equipped with a preheating system.
I tried to rig up a cheap one, but you can't find a good functional ceramic heater anymore with a metal shell. All the ones today are plastic shells and they're also tapered and sleek, lousy for screwing on a duct adapter and some ductwork to pipe into the exhaust opening of the cowling for preheat.
After some investigating, I ordered a system from Reiff Preheat Systems. It consists of four bands which, using worm clamps, clamp around each cylinder, and a heated element that is bonded onto the bottom of the oil sump.
Today I set about installing it.
The cylinder bands went on fine, but it's a bit of a struggle to get the system to fit if you have a Lightspeed coil on the top of the engine, as well as a fuel injector spider sitting up there, too. The heating element wire from the #4 cylinder is going to be too short. Drat!
The harness goes along the top of the engine block, which is a problem because of the Lightspeed coils, which I removed for a little elbow room. I'll try to clamp it to the case bolts with offsets and Adel clamps, but it's going to have to take a sharp turn to avoid the coils and, more important, the stainless lines coming off the fuel spider. I'm not crazy about it.
Meanwhile, work progressed on the oil sump. I used paint removing, a scraper, and some stainless steel to remove and prep all the paint on the bottom of the sump.
Then I mixed up the supplied epoxy -- it looks like a JB Weld type of product -- and attached the heater element, the wire from which will snake up the back side along the engine mount, through the baffle and attach to the harness.
Now it has to cure, which is a problem because, well, it's cold. It takes 24-48 hours at 75 degrees and goodness knows how long it'll take at 30 or so degrees in an unheated hangar.
But, it's not as if there isn't more work to do. The wheelpants all need to come off because snow is packed up inside them from taxiing over to the new hangar.
I don't know when I'll fly again.