Wear from cold starts and inactivity

Domenick

Domenick

Pattern Altitude
Joined
Sep 11, 2019
Messages
1,817
Display Name
Display name:
Domenick
Heading into fall/winter ...

Here in the Pacific Northwest our falls and winters are long, damp, and dreary affairs. Weeks or a month can go by without favorable VFR weather windows. Planes, such as my Warrior, can easily sit for weeks or even months.

When an engine is started after long activity without preheat and without pre-oiling, which parts are affected most, and precisely how might they attribute to reduced engine longevity?

I had good luck with my last engine despite long periods of inactivity. What might account for my good luck?
 
I think this article will answer your questions. https://www.avweb.com/ownership/the-whys-and-hows-of-preheating/

That being said, I'm just a few miles up the road from Harvey Field, and

1) I rarely have a week go by (even in the coldest/wettest months) that I can't get out and fly for at least 45 minutes. Even doing a half dozen touch & Go's in the pattern with an 1,800' overcast is perfectly doable.

2) A simple preheater is easy to make. Its no big deal for me to go to my unheated hangar on those rare days that preheating is really needed and set up the preheater then go to breakfast. A couple hours later, I'm good to go.

On most days, a real "pre-heating" isn't needed. Just aiming a hair blow-dryer into the lower cowl (for 15 minutes or so) is all I do. And then, its just to warm up the carb/fuel lines to make hand-propping easier.
 
Last edited:
We have the "problem" in reverse in the Southwest because of the heat. I haven't flown in a couple months due to the heat and the monsoons. I could also blame it on my work schedule but the actual problem is that I'm not willing to stay up late and get up early, or get up early and stay up late. If I'd make an effort to fly, I could but I also think that flying needs to be fun. Roasting in a plane and getting bounced around by the thermals isn't fun so Broom Hilda sits in the hangar and I feel guilty every time I go in there. But fall is coming even though yesterday's 100 degrees isn't much of an indicator. At least it wasn't 112.
 
I park my archer in a heated community hangar from late November through early March. (I live in NH). When the snow is gone, I hook up a GPU and crank it without priming until I get oil pressure. It takes about 10-15 seconds of cranking to get the oil pressure up. Then I prime it and start it normally. Usually the OAT is in the 50 - 60 F range. That seems to do it for me. Last annual comps were 78 78 78 78.
 
Domenick said:
Weeks or a month can go by without favorable VFR weather windows. Planes, such as my Warrior, can easily sit for weeks or even months.
Click to expand...

o.m.g. Don't do that!
Your engine will surely become a 5 gallon pail of aluminum/iron oxide in no time.
As a airplanitarian gesture, I would like to offer to have anyone from the PNW store their airplanes on my ramp in SW Texas where the winters are largely dream-like - no charge - and I pledge to fly them regularly.
Please leave keys (and credit card) in side pocket.
 
Let'sgoflying! said:
o.m.g. Don't do that!
Your engine will surely become a 5 gallon pail of aluminum/iron oxide in no time.
As a airplanitarian gesture, I would like to offer to have anyone from the PNW store their airplanes on my ramp in SW Texas where the winters are largely dream-like - no charge - and I pledge to fly them regularly.
Please leave keys (and credit card) in side pocket.
Click to expand...
That’s the spirit! :)
 
Timbeck2 said:
Roasting in a plane and getting bounced around by the thermals isn't fun so Broom Hilda sits in the hangar and I feel guilty every time I go in there. But fall is coming even though yesterday's 100 degrees isn't much of an indicator. At least it wasn't 112.
Click to expand...

I affectionately refer to my bubble canopy experimental as an E-Z Bake Oven in the summer. The best part of a hot summer midday flight is opening the canopy after landing.

Yesterday was not so bad as a friend was driving 1-1/2 hours to another field to rent an LSA for an hour of practice. I left early and it was an extremely smooth and cool ride over to and down the coast to hang out in the shade, sitting on the porch of the FBO, watching several students doing touch and goes. The ride home in the middle of the day was a bit warm and somewhat bumpy but not too bad. Sky was broken at 2500' so I did a bit of low and slow for the 30 minute ride home.

All that to say, "I feel your pain!" ;)
 
Yes, an effective preheat is needed, But moisture and acids in the oil is the detrimental factor causing corrosion. If nothing else, fresh oil and filter before winter.
 
Wear isn’t the problem. Corrosion is. Shorten oil change interval to 25 hours or 3 months is the best thing you can do.
 
Stewartb said:
Wear isn’t the problem. Corrosion is. Shorten oil change interval to 25 hours or 3 months is the best thing you can do.
Click to expand...

Agree. It's not the "wear", it's the corrosion from inactivity and accumulated moisture and acids. If not flying often enough, use CamGuard and increase frequency of oil changes. Oil is cheap. Iron and aluminum is expensive.
 
I use Decalin to help prevent lead build up from the 100LL. I also use Mogas when available and this helps to keep the engine cleaner by having less lead suspended in the oil.

Don't know how effective it is but I was told that sealing the exhaust shortly after shutdown helps prevent corrosion on the valves ...
 
Domenick said:
Heading into fall/winter ...

When an engine is started after long activity without preheat and without pre-oiling, which parts are affected most, and precisely how might they attribute to reduced engine longevity?

I had good luck with my last engine despite long periods of inactivity. What might account for my good luck?
Click to expand...
I would bet your luck comes from caring♥️, regular oil changes, proper warm up before laying power down and proper temp control. Knocked wood for you.
Is what you think of as cold really all that cold?
Detriments are the same as any engine I suppose, camshaft/lifters then rings/cylinders take the brunt of cold start cold oil wear. Either are generally a gradual loss of power, not catastrophic. I don know these engines really but guess since it's air cooled the rings are "loose" and being low revving the cam profile is kinda mild so no crazy stiff valve springs are needed that would exacerbate wear. Correct me if wrong. The oil seems like heavy but super boosted diesel oil to help suspend the bad by-products and moisture that can become acidic. Ya, they can cause spalling but their main kill is the colored metals of the various bearings.

I've always wondered when they are settling on a TBO, was it the same parts that were near the average end of their life or too many things to bother with, so overhaul it all?
 
Last edited:
Domenick said:
I had good luck with my last engine despite long periods of inactivity. What might account for my good luck?
Click to expand...

What are you qualifying as good luck? If you're saying you just haven't had any engine issues (yet), there could be a lot of things.

Engine startup wears parts until the oil is flowing, but that's just a small part of engine wear. There isn't much you can do about that except preheat in the winter to make the oil flow more easily during startup.

If you run your engine at the proper temperature, you'll have good "luck" with cylinders and valves. The recommendations I've seen is to keep CHT temps below 390 to promote longevity. Sometime in the past couple of years, I remember an article (Mike Busch?) that analyzed what happens chemically with different gas temperatures and the effects of different temps, but I don't remember which magazine that was in - AOPA PIlot, SportPilot or Kitplanes, but no memory of which. If you're at the right temp, you get complete combustion and the gases are still hot enough to prevent buildup on valves.
 
Robert Gee said:
I would bet your luck comes from caring♥️, regular oil changes, proper warm up before laying power down and proper temp control. Knocked wood for you.
Click to expand...
I do all that. I cringe when some yahoo jumps in a plane, starts the engine, and revs to 2000 rpm to warm up the engine. I installed a simple CHT monitor with the new engine. In the Warrior, it's easy to ALWAYS keep temps below 400F. Occasionally, I'll have to shallow up the climb or level off for a bit.

Robert Gee said:
Is what you think of as cold really all that cold?
Click to expand...
Below 60F. I suffer from relatively thin Mediterranean blood. :)
In truth, the PNW lowlands do not get very cold in winter, but it is damp. High 20sF some nights in the depth of winter is about it. Rarely, do we get a true cold snap of less than 20F. I'm not flying regardless of the weather at those times. Most days rise into the mid 40s.

bflynn said:
What are you qualifying as good luck? If you're saying you just haven't had any engine issues (yet), there could be a lot of things.
Click to expand...
Ran the last )-320-D3G engine out to 2925 hours. It too suffered long bouts of inactivity in the same location. Ran AeroShell 15w50. Changed oil and filters religiously every 50 hours. Leaned aggressively. No CHT, no EGT gauges.

Despite my previous success with AeroShell, I switched to Phillips XC 20w50 plus Camguard for the new engine. Time will tell if that was a good idea.
 
Domenick said:
Leaned aggressively. No CHT, no EGT gauges.
Click to expand...

As you lean more aggressively, you'll lower head temps. I'd bet you leaned aggressively enough to reduce the head temperatures enough to promote longevity.
 
I can't get many people to comment on the small O-200 engine as far as CHT. Mine, and most C-150, don't have any temp gauge other than the oil temp. That stays in the green in the summer and winter, but quite low in the winter, except that time that I climbed SL to 13'600' in one go when the temp finally got to the middle of the range at 10F OAT.

Is this engine just not large enough to really worry about the CHT? I can lean the engine out until the RPM starts to drop and have almost 200 RPM to play with before it gets rough or shuts off. Perhaps it just happens to be well balanced in all cylinders and I can actually run LOP. Obviously I can lean any way I want below 75% power, but does anyone have a 150 with a CHT gauge that has seen dangerous temps and can let me know an example of a setting that has been found to be too hot?

Anything other than running full power for 30 minutes at SL on a 100 degree day leaned at just the wrong spot going to actually cause any damage?
It is anemic enough that leaning for a hot heavy takeoff under 4000' density altitude could be a good idea at a short strip, but that is exactly what you are "not supposed to do".
 
All the talk about preheat is mostly conjecture. Continental still uses <20* F and Lycoming <10* F for the temperature to require preheat as long as the engine oil is appropriate for the weather. I've never seen anything scientific about added engine longevity due to preheating at higher temps. Maybe we should preheat to 220* full time. Eliminate corrosion!
 
You must log in or register to reply here.
Back
Top