Temps Requiring Engine Preheat

[201er]

Well it's getting chillier, that's for sure. I bought my Mooney in May so this is going to be my first winter. What temperature requires preheat for sure? What temperatures do you suggest heat but can get away without it?

One of my concerns is going places in winter. I may be able to preheat it at my airport but may not have access to heat at the destination if I shut down for more than an hour. Actually how long can you shut down for in the winter and manage a start without preheat again?

All advice pertaining to winter preheating for engine is much appreciated. And please don't suggest a hangar or built in preheat system because I'm still recuperating from the purchase so these are not going to be happening right now.

[Cruiser]

I like to preheat anytime the temp drops into the 40s. I always preheat if the temp is in the 30s. I also change to Aeroshell 80W instead of 100W during the winter.

I have the Reiff preheat system installed on my engine and the plane is in a hangar. I do not leave the preheat on. I go to the airport and preheat overnight if I have a morning departure.

It takes a long time for the internal engine to cool. One trick I was taught is to park the plane with the nose point downwind so the air does not blow through the cowling and cool the engine while you are parked. You can also throw an old blanket or sleeping bag over the cowl to help retain the heat. How fast it cools depends on a lot of factors but I would say three or four hours would not be too long a downtime.

[carusoam]

100ll does not evaporate well below 25 deg F.

Best regards,

-a-

[rocketman]

I agree with the above, do not preheat your engine overnight. One or two hours is optimum, beyond that creates problems according to several overhaul shops. There are timers available to activate the preheaters from the warmth of your home before heading out. Well worth it

[Jeff_S]

Quote: rocketman

I agree with the above, do not preheat your engine overnight. One or two hours is optimum, beyond that creates problems according to several overhaul shops. There are timers available to activate the preheaters from the warmth of your home before heading out. Well worth it

[Jeff_S]

Lycoming has a circular that talks about pre-heating, and they basically say that temperatures in the 20s are still acceptable to start without it.  Most people think that's crazy, and I would say that if you have any facility at all for avoiding this then you should. But at least you know what the manufacturer states.

As to the day trips, I would agree that unless you are in very frigid temps and pointing right into the wind, even up to 4-6 hours would probably not require a pre-heat. Just leave your cowl plugs in and point it away from the wind, into the sun if possible.

The fun part at that point is determining whether or not to consider it a cold start or a hot start! Each engine behaves like its own little recalcitrant child in these conditions, so you just have to experiment to see which method yours prefers.

[201er]

I expect to begin using preheat pretty soon. Can you guys give me some pointers about using a gas heater. How long/where you want to be pointing the hose? My guess is cap one cowl plug and stick the hose in the other, cowl flaps open, low heat for 15 minutes and then switch sides. Any reason for sticking some heat through the oil window and heating up the back?

[jetdriven]

Stick the scat hose from the heater in one cowl flap, maybe the right one because the left side is oily. Leave the cowl plugs in to trap the heat, give it enough time to get the engine and oil up to 50 degrees or more.  A really hot heater like a turbo heater may only take 15 mins. I think a hairdryer can do it in 45 mins.

[201er]

Wait so stick it in the cowl flap and not the front cowl opening?

[jetdriven]

heat rises.  You really need to get the crankcase and oil warm.  Thats the real reason.  The cylinders are all thats going to warm up if the hose is put in the front of the cowl.

[Piloto]

Because of the different types of oil my preheat criteria is that if oil does not drip out of the dipstick then preheat. Engine warm enough for start when oil drips out of the dipstick.

José

 

[201er]

Thanks guys, good advice. Anything to watch out for when preheating? Anything at risk of melting? What's too long a time to preheat? Where do you aim the hose when going up the cowl flap?

[John Pleisse]

I have a Tannis Heater. Having extensive experience with pan heaters, you need more if you live in the northern half of America. The Rieff or Tannis work well, they both require 2-6 hours for complete pre heat.

If you live in cold weather...this is essential. 90% of cylinder wear occurs on start up (not running 50 ROP).

[Shadrach]

 

Hair Dryer $12

Aluminum Cloths dryer duct $9

Base board heater thermostat $32

Water Heater Jacket X 2 cut to fit $45

old scat tubing $0

Total under $100.

Plane is stored with oil door open and dip stick vented. 

Thermostat maintains a cowling and engine temp of approximately 43df.

electricity is included in the Hanger rent.

 

3 winters and still going strong.:cool:

 

[aviatoreb]

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=1&threadid=115

This is a good thread that discusses preheating options.  As for temp, anything below 40 deg f and I use a pre heater.  If you use one with a thermostat, just set it and forget it.  The engine will always be warm enough for a quick start.

ATB...GP

[GeorgePerry]

Quote: aviatoreb

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=1&threadid=115

This is a good thread that discusses preheating options.  As for temp, anything below 40 deg f and I use a pre heater.  If you use one with a thermostat, just set it and forget it.  The engine will always be warm enough for a quick start.

ATB...GP

[triple8s]

I have always chuckled about all the fuss over hot starts, why just this past summer I was getting fuel and watched a fellow give up trying to restart a hot engine, well wintertime is almost here and as they say turn about is fairplay. If it is below 30df I'm sure its very amusing for someone to watch me get started. I have to pump the throttle and go pull it through several blades, then crank, and if that doesnt work repeat. (after 3 or 4 of these I am plenty warm) Only time this happens is when I park out of town and my 200ft of extention cord isnt enough to reach 120v. Is there not an STC for a primer on O-360 equipped Mooneys?

[PTK]

Lycoming recommends preheating the engine at 10 deg F or lower. This sounds way too too cold imho.  I typically preheat anytime temps dip down in the thirties.

[Jeff_S]

Ross wins the MacGyver award so far!

[Seth]

I have been told by some to heat below 50, below 40, and below freezing.  Without a doubt, pre-heat if there could be any ice from moisure.  I had no pre-heater built into my old F model, so I took a $10 space heater, and hooked up a dryer hose.  It would sit under the aircraft and the house would blow into the cowl flap as described during my preflight.  Now that the current airplane has a plug in pre-heater, which I used yesterday in Green Bay before departing back for Maryland, I plan to use the heater system I put together to blow some warm air into the cockpit, specifically toward the avionics to heat them up. 

I would heat without a doubt when it was below 40.  If it was near 50, and sunny, I'd just pull the plane out into the sun.  With the plug in heater on the Missile, I'll worry less, as I can just plug it in.  I do not plan to plug it in except for overnight the night before.  If it's going to be an evening departure, I'll plug it in earlier in the day.  The airport is about twenty minutes from work and home.

Take care,

-Seth

[Shadrach]

I Like the idea of a plug in heater, but I'd make sure that the cowl was blanketed. I "redneck engineered" my set up to avoid fluctuations in temp. The engine bay is held at a relatively constant temperature (~45df) regardless of OAT. I was able to verify the validity of this approach when I split the cases last year (CC crack) at 10 yrs. and 830SMOH. The engine internals looked fantastic. The only exception to this were a few (and by few I mean 1 to 3 tiny pits on each lifter, one of the lifters was completely pit free) almost microscopic pits on the lifters that were discovered after they'd been cleaned. The engine builder said that they would have likely gone to TBO or beyond. Other than that, the cam, cylinders and all other internals looked great. This was after years of being told by the "smarter guys" that I was turning my crank case into a terrarium...

[Shadrach]

Quote: Jeff_S

Ross wins the MacGyver award so far!

[John Pleisse]

One thing that a pre heater can do well, in addition to protecting cylinders and rings, is minimize wear on batteries and starters.  On a 25 drgree morning, I prime for 8-10 sec's and I literally just touch the ignition swith and it starts right up.

In my opinion, a good preheater (including MacGruber's-...SNL bit Ross ) pays for itself, perhaps in one prolonged winter.

[thinwing]

I just returned from a hunting trip to Montana.Preheat was required twice because temps were in lower 20s...I have a reiff heater that brings oil and cylinder head temps to 85 or so in 2 hours use.Basically call the fbo and tell them to plug her in...k

[Lowbid]

Although I don't have a Mooney (yet), in Wisconsin I use a Tannis on my C172 and turn it on the night prior for a morning departure or a few hours prior for an afternoon.  I don't worry about any temps above the 30's.

I also have a small ceramic electric heater in the cabin that I plug in at the same time.  It's great to get into a warm cabin at -20F!!  I use a custom cover from Tannis over the cowling (and prop which is important; the prop acts as a radiator to bring cold into the engine) but wish I'd have bought a Kennon.  For overnight at destination airports, I have yet to find an FBO where I could not plug in the Tannis.

Does anyone know of a device which will switch on the electricity in the hangar for the Tannis from home?