Engine Preheat Systems

[Utah-Jay]

I saw an Anti-Splat unit yesterday, looked very nice and well built

[BravoGolf]

This is the Anti-Splat oil heater. The length including the cord is 30”

[whee]

Hmm. A XP Reiff system doesn’t even provide that kind of preheat performance. Perhaps the starting point is the difference.

If I was dealing with freezing and above temps then an oil only heater would be great. Turn it on for an hour then good to go. But we see freezing temps when camping mid summer and sub-zero during the winter. It was -11F this morning and 5F when I got to the airport.

[jaredyates]

Similar results here.

[Battson]

For my engine, when the oil sump preheater was on, the oil was around 60*C (140F) after an hour's heating. The engine itself (CHTs) were sitting around 20*C (70F) from memory, which is plenty hot for all parts, it swung like a hot start, very easy starting.

[whee]

A quote that makes the point better than I was able to:

“How significant is this problem. Well, take the TCM IO-520-series engines used in manyBeech and Cessna singles and twins, for example. The IO-520 overhaul manual lists theminimum crankshaft bearing clearance as 0.0018 inch (that’s 1.8 thousandths) at normalroom temperature.

What happens to that clearance when you start cooling the engine down? TCM doesn’t say.But tests performed in 1984 by Tanis Aircraft Servicesin Glenwood, Minn. (where it gets mighty cold) indicated that an IO-520 loses 0.002 inch(2.0 thousandths) of crankshaft bearing clearance at -20F. An engine built to TCM’sminimum specified bearing fit at room temperature would actually have negative bearingclearance at -20F-in other words, the crankshaft would be seized tight!

You’ve probably noticed how difficult it is to pull the prop through by hand beforestarting in cold weather. Now you know why. It’s not that the oil is thick (because if youuse multivis oil, it’s not). It’s that the clearance between the crankshaft and bearingsis tighter than normal. If it’s cold enough, you might not be able to pull the propthrough at all.”

https://www.avweb.com/ownership/the-whys-and-hows-of-preheating/

[Battson]

I will be installing a preheat system on my IO-540. Looks like the choices are limited, either Tanis or Reiff. The Reiff is somewhat cheaper. The main difference between the two is the Reiff uses a band around the base of the cylinder, while the Tanis uses a threaded plug that replaces a rocker cover bolt. The heating philosophy is different, Tanis says can remain plugged in continuously up to 100 deg ambient, Reiff says only use before flying. Would like to hear from builders with experience with either system.

I didn't use either of those.
I used a sump heater pad. As far as plug-in electric heaters go, I loved it and would definitely do it again if that was my requirement - but for anyone going backcountry overnight, electric heaters are clearly of little use, so I haven't continued with it.

To my simple way of thinking, heating the oil sounds much better than either the Tanis or Reiff based on very little reading - why heat the cylinders when it's the oil and block which soak up all the heat? If the oil is piping hot then the cylinders are more than warm enough, from my experience with the system.

[500AGL]

The dry-air / dehumidifier systems some of the guys have come up with seem to be quite nice. Threads on SuperCub.org and I’m sure vans as well. Something worth considering for anyone that doesn’t fly often. Biggest issue with moisture is an engine that doesn’t run often, or very long. You have to fly at least an hour at 190* for the oil to burn off contaminants.

For the price and effectiveness the oil probe heater from anti splat seems great. For long term the Reiff is the whole package, we have installed many.

If you’re on a budget, on bush wheels and have a spare plastic barrel here’s an option. Cut out an opening on one side a bit larger than your kerosene salamander heater. Cut the top out and place it under the engine. Fire up the heater a good 2’ away and the barrel sends all the heat up into the engine cowl via the bottom opening. Cowl cover or blanket over the top and In 20 mins oil goes from 10* to 60*, and heats everything.

In the field it’s hard to beat the independence of a propane stove and straight duct up into the engine compartment. Nothing needed but a spark.

[m.mooney]

It’s a Baja 700/900. Weighs around 17lbs. Reiff system with sump heater and the cylinder band heaters come in below its capacity so it works great. Engine blanket on, plug in the gen, drink coffee until the gen quits, go fly. I had a Northern Companion in my 180 and thought that was great but I like this much more. Considerably safer and can pull double duty charging electronics. The weight is the penalty but I feel it’s still the best system.

[BravoGolf]

I ordered the Anti-Splat heater for my O-360 in my RV-7. I don’t think it would replace a dehumidifier system but for shortening the time I spend waiting for the engine oil to warm up it seems like a good product. I tried a heater pad attached to the sump but it didn’t heat the oil sufficiently.

[jaredyates]

I have a Honda 2000w generator set up to run on propane or gasoline. It was an aftermarket kit.

[whee]

What generator do you use that runs on the small propane bottle?

[Utah-Jay]

That new Anti-Splat heater for under $100 looks amazing. They sold out (Vans guys bought them up quick) in under a week I believe. A buddy across the hanger taxiway last week was “heating up” his engine with a propane heater and the tubing caught on fire while I was standing there watching. The flames were within 2’ of his engine cowling. I was stepping back and very concerned, as a Vietnam helicopter pilot he seemed unfazed. I gave him the link to the Anti-Splat heater and he ordered one before they sold out. Looks like a very good item. There is a long thread about it with many questions answered by Allen from Anti-Splate over on the Vans forum.

https://vansairforce.net/community/showthread.php?t=212297

[whee]

The anti-splat oil pan heater is a good one I think for heating oil in the oil pan two hours before flying. If we Preheat then fly with Reiff or an oil plan heater we generally are doing just fine avoiding metal-metal contact during start. Don't leave it on all week, or all winter to avoid condenstaion. Just a couple hours prior to flying.

Keep an open mind if its real cold. Cylinder scuffing is an issue at some cold temperature CHT. Do some data research of your preheaters ability to raise the CHT. If I can't get 50F then I'd be shopping.

Engines generally don't wear out, they rust out. If the cam, cylinders and prop hub are colder than the dew point, then condensation or frost form. My goal is to make aware that an unhealthy environment can be unknowingly be fabricated by its owner.

I've seen frost inside my hangared C-140's C85 engine through the oil dip stick one Michigan morning in November. Today I'd fix that after a flight by using a hair dryer to blow hot dry air into the oil dipstick out the crankcase breather for 30 seconds then hook up the dehydrator before I shut the hanger lights off. But this is not a rust thread, its a preheat thread....the two dovetail together though as a preheater can produce condensation.

Good point Brooks.

Cylinder scuffing, zero clearance at the crank bearings, zero clearance at the cam, etc. Heating the oil doesn’t take long but to get those critical and expensive internal engine parts takes time, several hours.

I too have seen frost inside the dipstick tube of an engine on a cold day. Moisture exists and we just have to decide how we want to deal with it.

[Bcone1381]

The anti-splat oil pan heater is a good one I think for heating oil in the oil pan two hours before flying. If we Preheat then fly with Reiff or an oil plan heater we generally are doing just fine avoiding metal-metal contact during start. Don't leave it on all week, or all winter to avoid condenstaion. Just a couple hours prior to flying.

Keep an open mind if its real cold. Cylinder scuffing is an issue at some cold temperature CHT. Do some data research of your preheaters ability to raise the CHT. If I can't get 50F then I'd be shopping.

Engines generally don't wear out, they rust out. If the cam, cylinders and prop hub are colder than the dew point, then condensation or frost form. My goal is to make aware that an unhealthy environment can be unknowingly be fabricated by its owner.

I've seen frost inside my hangared C-140's C85 engine through the oil dip stick one Michigan morning in November. Today I'd fix that after a flight by using a hair dryer to blow hot dry air into the oil dipstick out the crankcase breather for 30 seconds then hook up the dehydrator before I shut the hanger lights off. But this is not a rust thread, its a preheat thread....the two dovetail together though as a preheater can produce condensation.