Engine preheat guidelines?

[FloridaMan]

I'm in south Florida and I doubt it gets cold enough for me to need to use the preheater that's on my engine. However, I could see it happening when I'm up north. At what temperature and for how long should I run the preheater? How do you handle it with an FBO? Is it an expected service in cold climate? Do you tip extra or anything?

[jetdriven]

According to Lycoming SI1505, preheat is required for a cold start below +10f. I would warm it below 30-40f. They recommend using forced hot air. Overnight in a warm hangar would be a good solution as well. I haven't seen any of these preheaters that do a god job of heating the crankcase, a 200w pad on the bottom of the intake plenum won't heat the crankcase effectively.

[Marauder]

I'm in south Florida and I doubt it gets cold enough for me to need to use the preheater that's on my engine. However, I could see it happening when I'm up north. At what temperature and for how long should I run the preheater? How do you handle it with an FBO? Is it an expected service in cold climate? Do you tip extra or anything?

If you are at a small airport you might get lucky and have them do it for free. I usually just tip them for their troubles. But with the increasing fuel prices, most FBOs are usually charging something either for a pre-heat or for you to stick in their heated hangar. Before I go to a new airport in the winter, I usually ask this question along with what their overnight rates are.

[aaronk25]

I installed a reiff heater a month ago and it has 2 100w heat pads on the sump with a 165 degree thermostat epoxied onto the opposite side of the sump. Also has 4 100w bands around the cylinder. I keep a 200w "my heat" brand heater in the cockpit to make it less chilly but to preserve the gyros mainly. On start yesterday it was 10 degrees in the hanger at Rochester MN and my jpi 830 said the oil was at 145 and cylinders at 140......nice and toasty. I also run aeroshell 100w w/ cam guard and NEVER start the plane without at least some preheat below 45 degrees. But I'm also hell bent on proving that my engine will make it 3000+ hours.

[jetdriven]

Those heat pads do not go on the oil sump, they attach to the bottom of the intake plenum. i wonder how much heat makes it to the oil sump and the case?

[aaronk25]

Byron,

Funny you said that because I was looking at it and thought that because its quite a bit of distance below where the crank was that might be the deal. Il take a picture later today. But I also was looking at where the quick drain oil drain is at and it either level or its below where the pads are. Ill get you a pic. I uses my laser heat gun and shot it down the dipstick and it was saying approximately 140. And when pulling the dipstick the oil felt hot. So if the pads arnt on the oil case the heat must be conducting upward enough to warm. I also use cowl plugs to keep heat in. Also weird but if I use the same amount of "prime" that I do in the summer it gets flooded. So I think the engine/cylinders pistons are warmer in the winter with the preheater thank a normal MN summer day of 80d.

[rocketman]

I use a $50 small ceramic heater (Wal Mart) and connected a short piece of SCAT tubing to the end of the heater and place this in one of the open Cowl Flaps. Simple and inexpensive. And unlike the Reiff or other heaters that heat the cylinder and oil, this method heats the entire contents under the cowl. Everything stays warm including the very important Turbo charger. I also purchased a $300 cell switch that you can use it to switch the preheated on or off with a text message from your smart phone. The cell switch operates off of T-mobile and you can get t-mobile to operate this for 20 cents a message. This way I don't have to wait the two hours or so at the airport while the engine is preheating while I'm "precooling"...

[yvesg]

Over here, we fitted at the end of this:

http://www.mrheater....?catid=46&id=28

with a duct reducer then a 4 inch aluminium flexible hose. We insert it through the pilot side cowl flap opening. Pre-heat for 30 minutes as soon as it gets below 32F (0C). We use a warm old sleeping bag on top and sides of the cowl to keep the heat in. The heater fan works with 120V AC however, this year the aircraft has moved to a tie-down where there is no power so I replaced the fan for a 12V one which can run off the car system.

Yves

C-FQKM

[aviatoreb]

I use a $50 small ceramic heater (Wal Mart) and connected a short piece of SCAT tubing to the end of the heater and place this in one of the open Cowl Flaps. Simple and inexpensive. And unlike the Reiff or other heaters that heat the cylinder and oil, this method heats the entire contents under the cowl. Everything stays warm including the very important Turbo charger. I also purchased a $300 cell switch that you can use it to switch the preheated on or off with a text message from your smart phone. The cell switch operates off of T-mobile and you can get t-mobile to operate this for 20 cents a message. This way I don't have to wait the two hours or so at the airport while the engine is preheating while I'm "precooling"...

I have a Rieff heater that I installed immediately upon purchase since in the heart of winter -25F is not uncommon.

In the big picture - details aside if you pump enough watts efficiently under the cowling, things will heat up. I use a proper thermal cowl cover and EVERYTHING under that cowl, including the cowl itself, and including the turbo I assume, is toasty warm even if it is subzero out. Seeing 100F on the engine temps on the JPI before engine start is common even if it is subzero. I am of the opinion that a mounted oil-and-cylinder heating system conducts through out and it likely heats faster and more uniformly than a heat pump system you described. I have the Rieff turbo system.

Okay - and for one of the top ten long running debates ...I run my Rieff full time. I believe it chases moisture (when using a full heating cylinder system - not just the oil heater system).

[aaronk25]

I left my rieff on full time to and Blackstone labs said there was "0" moisture present. Rieff is a nice system , lots of power but my 4 cylinder bands all failed after 2 months. The warrantied them no questions asked. Hopefully just a defect with the ones I received, new ones are on and working good. 600w of power keeps it toasty!!

[jlunseth]

I pre-heat whenever it is under 40F. The engine will start by itself at that temp., but I have a pre-heater, the FBO will plug it in when I call, and why stress the starter anymore than necessary? I also give the engine in my 231 plenty of time to warm up the engine compartment. The TSIO-360-GB and LB have a direct drive alternator that has a rubber clutch. I have found that this clutch does not allow the alternator to kick in until it is warmed up a little, and I don't like the idea of the stubbornly cold clutch slipping when it tries to bring the alternator online, so I idle at something around 1000 rpm to allow the clutch to warm. I also had an issue last year where I did not do a very long warm up then flew to an airport about 25 miles away to try some fast approaches. I was planning a landing at our Class Bravo and thought they might want me to keep my speed up, so thought I would get ready for that. The first landing went fine, and out of habit I opened the cowl flaps on the ground as I taxied. It was our first very cold day here, around 0 F. On the next takeoff I noticed the oil temp very low so immediately landed. When I got out there were big oil streaks down both sides of the plane. The cold temps had caused the oil in the air-oil separator to sludge up and with no place for the internal pressure to go, the oil was leaving the engine through every available orifice. Not a big deal to fix, but easily avoided by letting the engine warm the engine compartment, and then leaving the cowl flaps closed during cold air ops.

[M20F]

I have a Reiff and as noted it heats everything exceptionally well. In answering the question of when you pre-heat just pull out the dipstick and look at the oil on it, if it looks like molasses probably would be a good idea to pre-heat. The temp at which this occurs is going to differ based on the weight of the oil being used and other factors.

My two cents

[mooniac58]

I just received my EZ-Heat "pad" style heater in the mail yesterday. I am planning on installing and testing it tomorrow. I did a lot of research on this before and my understanding is that the general misconception is that the concern is oil being too cold, but with modern synthetic muti-grade oils this is not really the case - however the real concern is the different expansion/contraction rates of the steel and aluminum parts in our engines. What you really want to do is pre-heat the cylinders and the cam shaft - or any place where metal parts in motion have tight gaps.

As I understand it if you want to pre-heat for 1-2 hours before starting you have to be careful which method you select - forced air or a warm hangar is best - something that is more ambient and very hot. If you have the time to preheat overnight you really can't go wrong just dumping energy about anywhere in the cowl (as aviatoreb said above) and it will distribute eventually to the entire engine more or less. If your oil and cylinders are 140F+ then I would imagine all concerns are at rest - as all parts of that engine are likely warmer than they are on a given summer afternoon.

Attached is the install guide for mine - it looks to go on the oil sump.

ez.pdf

[aaronk25]

If its -15c outside and you use insulated cowl plugs and preferably wrap the cowl with a insulated blanket you will be ready to go in maybe 6 hours probably 8.

The cylinder bands help quicken the heating time. I'm surprised how much heat transfers to the case from the rieff bands.

More power the better for pre heat and it doesn't really matter where it is to a point.

[John Pleisse]

I have had a Tanis heater for years. It is the bomb. I basically leave it on all winter, if flying regularly. I had the aforementioned oil pan heating pads with marginal results.

Two things I would hope someone could contribute:

1) Are there corrosion issues with "sweating" engines?

2) Has anybody had any luck with the old lightbulb trick? This always seemed far fetched and impossible to me.

3) Anybody turn theirs on with cell phone relay type products- I have been unable to find these

I also notice nobody provided effective warming times. Tanis says 6-8 hours. Rife? Lyc? Others? You have to find a plug while transient.

[aviatoreb]

I have had a Tanis heater for years. It is the bomb. I basically leave it on all winter, if flying regularly. I had the aforementioned oil pan heating pads with marginal results.

Two things I would hope someone could contribute:

1) Are there corrosion issues with "sweating" engines?

2) Has anybody had any luck with the old lightbulb trick? This always seemed far fetched and impossible to me.

3) Anybody turn theirs on with cell phone relay type products- I have been unable to find these

I also notice nobody provided effective warming times. Tanis says 6-8 hours. Rife? Lyc? Others? You have to find a plug while transient.

Is your engine sweating when it is plugged in with the tanis? Mine is bone dry when wrapped in cowl cover and plugged in. In fact, often there is a dable of water in the dip stick area immediately following a winter flight since oil dips below the magic 180F in the final decending phase on low power - and it stays there for days if I do not do something, but it is gone in hours when the engine is plugged in by the tanis. I do keep my tanis plugged in the winter through. My engine never knows it was even winter.

[Piloto]

I use this for preheat. I preheat when below 30F. I do not start engine until the dipstick drips.

[M20F]

I did a lot of research on this before and my understanding is that the general misconception is that the concern is oil being too cold, but with modern synthetic muti-grade oils this is not really the case - however the real concern is the different expansion/contraction rates of the steel and aluminum parts in our engines.

I would disagree with this, any type of oil is going to get viscous when it gets cold. Pumping that sludge through the engine, oil cooler, prop governor, etc. isn't a good thing. I agree with Piloto which is unless the oil is loose on the dipstick you probably aren't doing your engine a lot of favors by trying to start it.

[Jerry 5TJ]

How do you handle it with an FBO? Is it an expected service in cold climate? Do you tip extra or anything?

I never had to tip for preheat. The FBO normally adds it to my itemized bill.

If it is below 30F I prefer to heat the whole plane in a warm hangar rather than just blow hot air into the engine compartment.

[fantom]

......unless the oil is loose on the dipstick you probably aren't doing your engine a lot of favors by trying to start it.

I wonder about the impact to hundreds of millions car engines starting in sub freezing weather every day.

[aviatoreb]

I wonder about the impact to hundreds of millions car engines starting in sub freezing weather every day.

I am sure it is not super for them but there are two major differences. 1st they are all hard metals instead of the soft aluminum used in airplane engines - this is a major difference. 2nd, they are typically run every day so more likely to maintain a film of oil on all parts at all time.

Someone mentioned but I will reiterate - with dissimilar metals that expand and contract at different rates, there is a temp, a very cold temp where your engine is actually locked together - something like -30F just to make up a number on the rough order of the number I read once.

[danb35]

I wonder about the impact to hundreds of millions car engines starting in sub freezing weather every day.

How many cars use 20W-50 oil any more? Much less straight 50 weight? Most specify 5W-something, and many are now calling for 0W-. Also, most auto engines still have cast iron blocks, which will expand and contract at a rate much closer to the crankshafts.

[aviatoreb]

How many cars use 20W-50 oil any more? Much less straight 50 weight? Most specify 5W-something, and many are now calling for 0W-. Also, most auto engines still have cast iron blocks, which will expand and contract at a rate much closer to the crankshafts.

Exactly what I was saying - the crankshaft and case expanding the same was my point plus the fact that the cylinders are harder material. That said I do feel really ugly when I turn over my engine in my car on a frigid morning like -20F. Look at the map for KPTD and you will see we are pretty far north. North of a large fraction of those Canadians.

Oh - back to preheating airplanes - one nice thing about a Tanis - or a Rieff - if you want to do it frequently as we do in the great white north is simply the convenience. Just plug it in and you are done. I have in my previous airplane for a while gone through the setting up home made heaters routine and it is much more of a to-do.

I went to West Virginia about two weeks ago and the next morning when I wanted to depart it was 28F and to my surprise the airport had no preheat service and was not very helpful even with the request to lead a power cord to my airplane. Argh. So I delayed 3 hours since the temps were warming quickly and I left an hour after temps had reached 40F to give a chance for the engine to catch up. The radiant heat from the black taramac helps a bit I figured.

[RJBrown]

I wonder about the impact to hundreds of millions car engines starting in sub freezing weather every day.

There is a BIG difference between modern liquid cooled auto engines and our antiquated air cooled engines. Running clearances can get too tight cold and cause scuffing inside our engines. No comparison at all. Do not justify abusing your plane engine just cause car engines are OK with that kind of use.

I have the bands and pads type of heater. It gets turned on the night before a flight. I also have a heater like Yves G showed. 30-45 minets before the start can't hurt. Kind of a belt and suspender type of approach. I preheat any time it dropps below freezing. I cant always get the Tanis plugged in the night before, 8 hour minimum. I can always wait for my propane heater. For me plugging in means leaving a generator running, there is no 120v where I park.

[aaronk25]

So one thing I'm finding with my travels to major NE airports this week, somthing I had not done this time of year before, they are not good at letting you plug your plane in or for that matter even tell you where a plug in is! I have to leave Republic, long Iand airport at 9AM so I am getting there at 7AM tomorrow of which they said they don't have any outside 110V plug ins.

The gal at the counter is gonn get a suprise when I unplug her I phone charger behind the counter and run 150feet of cord out the door to the ramp. I have a honda 2000 and that will be my new buddy traveling with me....with a lock of course.

To bad Atlantic, never thought to have a spot to plug in piston aircraft.