Q: I go overseas almost every other year from October to early April. I live near McMinnville Municipal Airport (KMMV) in Oregon, just south of Portland, and we have the typical Pacific Northwest wet, cool, rainy weather through April.
I have a very, very tightly cowled experimental Midget Mustang with a Lycoming O-290G converted to a D. It was 125 horsepower when it was new and at 950 hours it is running strong with no issues.
I have done this long-term storage procedure at least every other year since 2008 before going overseas. My question: Am I doing anything to hurt the engine?
On the second to last flight, I get the temperature up, land, drain my oil (Phillips 66 X/C Aviation Oil 20W50 with an appropriate amount of Camguard). I refill with six quarts of Phillips 66 Aviation Anti-Rust Oil, add Camguard, then fly and get the temperature up.
I “double up” with the anti-rust oil and Camguard, perhaps unnecessarily, hopefully not a contraindication.
After I land and store the aircraft, I do not turn the prop.
I momentarily remove the spark plugs and with a mister squirt in a mix of anti-rust oil and Camguard, then replace the plugs.
I block all air access to the engine by plugging the four exhaust stacks, ram air intake to the carburetor, carb heat inlet to the back of the carburetor air box, engine breather tube, and cooling air inlets through the cowl, and the back of the lower cowl at the engine cooling air exit.
Additionally, I insert two incandescent 60-watt light bulbs. They give heat to the inside bottom of the cowl under the cylinders. I block the back of the lower cowl.
All air movement over, around, and into the engine is blocked and the lights keep the temperatures above 50°F through the winter. I also put a sleeping bag and thick blanket over the top of the cowl to retain heat.
By coincidence, I installed a carb heat gauge to watch for icing temperatures. Checking this, temperatures in the carb inlet throat are always at least 50° during storage.
I am wondering if my idea of keeping air from moving over and through the engine and temperatures at or above 50° is a good idea or if I may be causing harm. I don’t trust a desiccant pump to last. I have a friend who visits the hangar about once a week who swaps out the light bulbs if one dies.
I had an alternate idea of putting a bulb up by the back side of the carb air box inlet for carb heat, which would make the heat go directly through the inlet tubes to the cylinders. This would do nothing for the outside cylinder temperatures and, as said before, with the two bulbs lying on the bottom cowl under the cylinders and heat rising, I still get at or above 50° through the carb throat.
My biggest worry is doing something wrong and actually hurting my engine by unintentionally/ignorantly causing condensation and rust due to my “technique.”
I also use the bulbs and much less blocking of the intakes, etc., during the summer and flying season to keep temperatures just at or above 50°.
I will be leaving for Asia before too long and will follow my usual procedure, but I thought it would be a good time to actually validate this procedure with someone other than an amateur and liberal arts major, me.
Thanks for your attention. Any comments are appreciated.
Roger Ray
Answer from Paul McBride, the General Aviation News engines expert: Roger, I’d first like to commend you on your excellent description of your engine storage procedure. My head was nodding in the positive practically from the beginning and, as I reached the end of your procedure, I had no doubt that you’ve nailed it.
There has always been controversy about how to best prepare general aviation aircraft engines for long-term storage, but from my viewpoint, you’ve covered all the bases and then some.
I was especially impressed with your comment about not turning the prop. That is certainly one of the key contributors to keeping the engine closed up.
Most people think you should turn the prop in order to move the oil in the cylinders up and down the cylinder walls, when in fact it actually scrapes the oil off of the walls and opens and closes valves, which allows outside air into the cylinders. Of course, you already know all of this and that is the reason why your procedure is the proper way to store an engine.
I would like to comment on your use of various ways to completely block off any air movement around the engine. This is a very important factor because by having heat from the light bulbs, any flow of outside air around the engine would cause a differential in temperature of the various engine components which, in turn, would cause the potential for moisture. This is why leaving various engine heater products on continuously does more harm than good.
However, in your situation, you’ve got a constant temperature and zero outside air moving around the engine, which provides a very dry environment. I will admit that anything less than what you are doing would not make the grade.
Thank you so much for sharing your experience with all of us. Hopefully this will motivate more aircraft owners to consider following your procedure, especially those who reside in the colder climates or where flying may be limited by nasty weather.
I’ll pass along my best wishes for safe travels to Asia and know that your Midget Mustang will be awaiting your return for more great flying.
Wire two incandescent light bulbs in series. They will burn for years.
To the editor;
Reader comments on questions posed to GA New looks like they can be valuable info to the questioner, with a number of possible solutions to the problem posed.
This could be a valuable service offered by GA News….Thanks.!
nice
I’ve been doing most of this on two airplanes stored near Oshkosh for 17 years; it works for me. So I’ll also vouch for your method, Roger.
Instead of light bulbs, however, I use two 25 watt gun cabinet heaters that look like broom handles w/ a power cord on one end. They’re NOT intended to heat the engine … and don’t … just like your light bulbs. They’re intended to keep the ambient air in the engine bay dry and moving around … and they don’t burn out. It’s already relatively dry in WI in winter but these help along with sealing up the engine and covering it. I have a plastic plug on the exhaust tubes and silica gel inside, as well. I also have a third similar heater in the cockpit for the same reasons. Like you, I don’t trust long term use of dessicated pressure systems; they’re OK for short term use but not 6 months.
I remove the battery and actually transport it to my winter home in FL. That way, it never sees cold temps and I can keep it happy with a trickle charger … I use a Harbor Freight 4amp high freq unit that desulfates the battery. I have one battery in a stored pickup that’s now 17 years old !!
Of equal importance is the start up procedure; I use Mike Busch’s method. I remove the top four plugs and hand crank the engine until I see oil pressure (on a mechanical gauge). Once I see that, I then crank the engine for a total of about a minute with the battery. I put the plugs back in and run it as quick as I can. Once in a while, I use a borescope to see what I see.
The ONLY thing I see potentially wrong with Roger’s method is the use of multi-grade storage oil. As an A&P, I’ve noticed that straight grade 100W oils “stick” to my oil filter drain pan far better than multi-grade oils when it’s tipped up for draining. So I use 100W oil vs multi-grade. IF necessary, I pre-heat the engine with a small electric heater when it’s still cold out when I return to Wisconsin.
Larry, we are on the same page. I will look into the gun cabinet heaters as the 60 watt incandescent bulbs are getting hard to get and also burn out after about a week and require constant changing. I plug my stacks, as well as all other ports into engine and cowl with thick foam wrapped in old plastic bags. I have not used desiccant or silica gel in the stacks but will look into that. I too use the start up procedure after my return that you mentioned. And remove my battery to a heated room while away. As far as the Phillips multi grade storage oil I am not aware of a single grade alternative. I think Shell has a similar product. I will check. Thanks for the pointers, Roger
You might look at auto oil pan heaters on Amazon;
‘ KENUOS 2PCS Engine Block Heater Oil Pan Heater Pad with Thermostat 120V 150W 4 X 5 Inch 3M Self-Adhesive.’
I’d also recommend using dehydrator plugs in place of the upper spark plugs.
Jim, during a webinar w/ the company that produces the oil sump permanently attached heat pads, the former owner specifically stated NOT to leave it on for long periods. Those are intended to heat the oil just prior to a startup for reasons of viscosity and to reduce the shock heating of the startup of a cold engine. Your idea of desiccant plugs is a good one and since I have to R&R the top cowl of my engine to remove my battery, I think I will do that … I have some, in fact. All you need to do is to keep the air in the vicinity of the engine slightly above ambient and more stable (as in hangaring), condensation — the enemy — won’t form.
For Roger … I’ve been using the same gun cabinet heaters for nearly 20 years … you’re right … they don’t burn out like a bulb AND they’re safe around the engine. I got mine at Midway USA in MO. They’re saying they’re 12 watts ea.
See: midwayusa.com/product/1022581789?pid=176216
There are other low powered products that do the same job. I have a unit bought at a boat shop that is like a small aluminum bowl w/ a fan in it, as well … but a motor running unmonitored for 6 months doesn’t seem safe to me.
Larry, thanks again for the pointer and the link….I will def get those. As said the idea is stop moisture not heat the acft….during non Asian times, such as summer’s hot days, I dispense with most of this but use variations of the procedure as temps and the season warrant and I am constantly at the airport so can change out a light bulb as required. While gone in Asia I need a hangar buddy to look in my hangar once a week or so and check bulbs, I leave a stash of bulbs by the plane, and replace as required. Your gun heaters will really be a big improvement over this procedure.
The Shell product is Aeroshell fluid 2f.
I’m not sure but it may be a “fly away” oil like the Phillips product is. I use the Phillips Anti-rust product.
As a question, My thought is continuous heat reduces the viscosity of the oil film on all internal engine surfaces. The contradiction is; variable daily temperatures create similar conditions throughout the year. I don’t see a direct benefit for continuous heating unless breathing outside air is considered the issue. Stopping outside air infiltration is critical but is that possible during an extended storage period.?
The things you do is great, The next think you could do take the engine out and bring
home were it is warm. Great job.
Good preparation for the long time non running engine. Congrats to the owner.