Preheat

tkatc · #1 09-13-2011, 01:38 PM

As winter approaches I will soon need a preheat system. Search has turned up a few threads but I would appreciate some recent thoughts on the subject.

I like the Reiff system with sump and cylinder heating but I cant say I love the price. There are lower cost alternatives but they do not offer cylinder bands. I have another obstacle to overcome. I have a carbon fiber plenum so I need to find a way to penetrate the shroud to connect the wiring harness so I have only 1 plug under the cowl. I have seen plug wire grommets for 6 cylinder engines that might work nicely by using the 3rd grommet hole for the wiring harness.

Any pics and opinions welcome.

Rupester · #2 09-13-2011, 01:45 PM

... I have the full Reiff system. With the cylinder bands, the harness that runs on the top of the engine is about 1/2" in diameter where it exits the rear baffle for my SJ plenum in the back. I cut a hole and installed an EPDM grommet with either 1/2" or 9/16" I.D. The I.D. must be large enough to accomodate the rear connectors on the harness. Send me a PM with an email address and I'll send you pics.

Terry

lostpilot28 · #3 09-13-2011, 01:46 PM

I'm no expert on this topic, and I'm sure someone will square me away if I'm wrong, but I'm not sure of the "need" for cylinder heat. If I understand things correctly, when the engine is cold you want to get oil flowing as quickly as possible. Keeping the oil warm in the pan does exactly that. I'm not sure what benefit is provided by pre-heating the cylinders.

I opted for two small (2x4 inch) sump heating pads of 25 Watts each. They warm the oil up to the mid 60's in the winter. As far as I can see they do not cook the oil in localized "hot spots" in the sump because they're heat output is pretty low.

But again, I could be wrong. So far, though, it works for me.

pierre smith · #4 09-13-2011, 02:05 PM

Tony, I had only the two pads on the sump on both my last -6A (O-360) and now the -10....no cylinder strips.

It is so efficient that I only have my timer start to heat at midnight when it's in the 20's here and I'll have oil temps in the 80 deg. range by 8:00 a.m.. If you'll simply cover the cowl with an old blanket and stuff the loose ends in the cooling air intakes, she'll be nice and cozy, ready to roll.

The heat is transferred to the block and cylinders, so all of that is warm and seldom takes more than two blades to start up.

Best,

Neal@F14 · #5 09-13-2011, 02:15 PM

I had the full Tanis system in my old Cherokee 140, with the cylinder heating elements that screw into the CHT probe holes. The system as a whole worked very well, and when I still had the old boat anchor Prestolite starter on the engine, I believe the cylinder heaters were a significant benefit and probably necessary when the OAT was in the teens or twenties because that old starter didn't exactly crank the engine over with "gusto", especially when cold-soaked. After I upgraded to a SkyTec NL starter, I probably could've dispensed with the cylinder heaters, but being able to start up the engine with the cylinders up to at least 40 degrees F or warmer with the cylinder heaters warmed up surely has to be less stressful on the pistons and rings.

9GT · #6 09-13-2011, 02:29 PM

Save yourself some money, complexity, and weight. I live in Michigan where it gets plenty cold in the winter. I use the two small Reiff hot strips that have a thermostatic on/off. I plug the cowl inlets and throw a blanket over the top of the cowling. The engine gets nice and warm INCLUDING the cylinders in a few hours time.

SmilingJack · #7 09-13-2011, 02:42 PM

Tony,

I have the Reiff cylinder bands, sump pad and the oil cooler heat pad.

I know it was a little on the expensive side, but I did this to insure I was able to preheat the engine quickly if I forgot to plug it in over night or was not at home base.

I agree with the others, if you have at least 1 heating pad and place a blanket over the cowl you will have plenty of preheat.

One thing, if you choose to go with the sump heat, I recommend adding the oil cooler heat pad too, as you may not get the heat transfer from the engine to the oil cooler and then chance damaging the oil cooler.

Good luck,

Greg Arehart · #8 09-13-2011, 03:47 PM

Tony,

I have the Reiff bands plus sump heater and am happy to be able to plug in for an hour and be ready to go. I have a remote cellphone activated switch, so I just call the airplane an hour before flying and it's ready to go.

For a plugin, I just wired my heaters to a computer plug (standard three-prong plug from an old power cord) which I mounted to the baffles just behind the spinner. I simply reach in through the air intake and plug in the heater. I have a little in-line LED on the extension cord that tells me power is on. No holes in the baffles. Just unplug and fly!

cheers,
greg

Ron Lee · #9 09-13-2011, 03:52 PM

All I have is a Wolverine sump heater and it is fine. I am in a hangar, use a packing mat over the cowl and plug the cowl inlets. Temps get up to 60 deg F or better after several hours.

I think the CHTs are close even with no direct heating source.

alpinelakespilot2000 · #10 09-13-2011, 03:53 PM

Quote:

Originally Posted by Greg Arehart

I have a remote cellphone activated switch, so I just call the airplane an hour before flying and it's ready to go.

Greg, can you elaborate on what it takes to set up something like this?