It's not uncommon to hear people say they turn their engine over by hand to prevent corrosion, when it's been sitting unused for a few weeks. Personally, I have never believed the theory behind the practice.

I was reading the link below, and see that Lycoming SB recommends not turning your engine over when it's been sitting in the hanger for a few weeks.

http://www.aircraftspruce.com/catalog/pdf/08-07086lyc.pdf

Does the same thing apply to TCM engines, or are they somehow different?

Additional post on a different but related subject - the first paragraph of this article from TCM confused the hell out of me:
http://tcmlink.com/fiddefault.aspx?cgroup=MATTITUCK&cpagename=GOODHABITS

Pulling the engine through BACKWARDS several times before each flight? I thought that could be harmful to the vacuum pump (if fitted)?

Battson wrote:It's not uncommon to hear people say they turn their engine over by hand to prevent corrosion, when it's been sitting unused for a few weeks. Personally, I have never believed the theory behind the practice.

I was reading the link below, and see that Lycoming SB recommends not turning your engine over when it's been sitting in the hanger for a few weeks.

http://www.aircraftspruce.com/catalog/pdf/08-07086lyc.pdf

Does the same thing apply to TCM engines, or are they somehow different?

Same physics for all piston aircraft. If you do that you will wipe the oil off surfaces and promote corrosion.

I did hear something interesting at an Oshkosh forum yesterday though. A study found that airplanes that self fueled had less corrosion that those that used a truck. Same airplane types, engine types and everything controlled.

The deal is that if you put the plane away hot then the oil doesn't adhere to the surfaces as well, and that's what people who use fuel trucks do more of.

People who self fuel often fuel when they are done to prepare the plane for next time. So they pull to the pump, shut down, the engine cools *a lot* while they fuel, they power up and taxi to parking having just slopped much cooler oil around a much cooler engine.

Also, it was reiterated that camguard is the bees knees. At this point it's almost foolish to not be using it (or an oil with the active ingredients already included).

DO NOT pull an airplane engine through by hand In lieu of flying it during storage.

If you're going to store it, PICKLE IT. Then don't mess with it.

If you THINK you're going to fly but don't, LEAVE IT ALONE until you can fly it. Turning it over by hand scrapes what little oil is left adhering to metal parts off, so when you actually start the thing, you'll have NO lubrication.

Same goes for ground runs during storage: engine temps don't get warm enough to evaporate moisture, which stays in engine and rusts it.

Leave it alone or pickle it.

Same goes for Lyc/Continental/P&W, etc.

MTV

Battson wrote:Pulling the engine through BACKWARDS several times before each flight? I thought that could be harmful to the vacuum pump (if fitted)?

I know this topic is not specific to Rotax, but the Rotax manual specifically tells you that rotating the engine more than one turn backwards will deprime the oil pump and cause oil starvation on the next start. Not good.

tom

mtv wrote:DO NOT pull an airplane engine through by hand In lieu of flying it during storage.

If you're going to store it, PICKLE IT. Then don't mess with it.

If you THINK you're going to fly but don't, LEAVE IT ALONE until you can fly it. Turning it over by hand scrapes what little oil is left adhering to metal parts off, so when you actually start the thing, you'll have NO lubrication.

Same goes for ground runs during storage: engine temps don't get warm enough to evaporate moisture, which stays in engine and rusts it.

Leave it alone or pickle it.

Same goes for Lyc/Continental/P&W, etc.

MTV

I've heard Mike Busch say this same thing in a webinar when talking about pulling a prop through when cold to "break the oil loose".

So how many of you use cam guard? I seem to remember reading that it was more effective with some types of oil than others...also more important during times of the year when not flying as much. What's your guys take on it? I'm not using it but maybe should start.

Grassstrippilot wrote:So how many of you use cam guard? I seem to remember reading that it was more effective with some types of oil than others...also more important during times of the year when not flying as much. What's your guys take on it? I'm not using it but maybe should start.

I was thinking about it a while ago, and did some research.

The advice I got was that it's not worthwhile for planes that fly once a week or more [if you live in a normal climate without a lot of pollution / salt / water], especially if you're using a higher viscosity oil like W100+ which clings onto the parts for longer. The multi-weight oils like 20W50, I understand, don't stick for as long a time - and in that case you might benefit from Camguard even if you do fly quite often.

Good to know. I use 20W50 and try to fly once a week. Based out of northern UT. Something to think about. Thanks!

I know this experience first hand! Our skylane sat idle in a hanger in the central valley from 1980-2001. It had a 200 hr engine in it when it was parked. The ranch mechanic would turn the prop 30 cycles per week and when he retired he taught the new mechanic to do the same thing. Also would change the oil in the engine every 3 months, it was never ran period in that time frame.

Fast forward to 2001, the plane is dusted off bought and flown to a shop. The engine is full of rust, and some corrosion on the cylinders. We kept flying it and watching compressions, they ended up getting a few below 40 something over 80. We could have topped it, but screwed it and put in the pponk engine. Steve took the engine apart and said topping it would have been short term, the thing was rusty and junk inside.

We did get a fair ammount of hours on it, but nowhere near tbo not even half i believe!

I ran 100W in the old engine, and run 100W in the new engine, with no additives like camguard. It is clean and i fly it regularly enough not to worry about it.

I never turn the prop over ever and i think the mechanic as good intentioned as he thought he was back then did a big disservice to the engine we had.

Mike

Battson wrote:

Grassstrippilot wrote:So how many of you use cam guard? I seem to remember reading that it was more effective with some types of oil than others...also more important during times of the year when not flying as much. What's your guys take on it? I'm not using it but maybe should start.

I was thinking about it a while ago, and did some research.

The advice I got was that it's not worthwhile for planes that fly once a week or more [if you live in a normal climate without a lot of pollution / salt / water], especially if you're using a higher viscosity oil like W100+ which clings onto the parts for longer. The multi-weight oils like 20W50, I understand, don't stick for as long a time - and in that case you might benefit from Camguard even if you do fly quite often.

The study, which has been posted here but I can't find at the moment, showed that the conventional wisdom on straight weight was invalid. It doesn't cling any better than multi and in some cases performed worse. The camguard was the only thing that mattered. Straight weight as the important disadvantage of not getting onto the surfaces that need to be lubricated as quickly as multi during cold starts. And start-up is when a lot of the wear takes place.

The forum this week said that another recent study (which he didn't cite) showed benefits for camguard even on engines run regularly. But, yes, if you are running your engine regularly you are still more likely to make TBO than if you don't, regardless of whether you are running camguard.

rw2 wrote:The study, which has been posted here but I can't find at the moment, showed that the conventional wisdom on straight weight was invalid. It doesn't cling any better than multi and in some cases performed worse. The camguard was the only thing that mattered. Straight weight as the important disadvantage of not getting onto the surfaces that need to be lubricated as quickly as multi during cold starts. And start-up is when a lot of the wear takes place.

It would be good to see that study.
The one in this article does tend to agree with you http://www.avweb.com/news/maint/oil_myths_debunked_197096-1.html

Yes the conventional wisdom says the opposite http://www.avweb.com/news/maint/182909-1.html?redirected=1

Keeping in mind we're talking about corrosion protection, it's worth noting that a multi-grade oil can absorb more water than a single-weight oil.

Ok - having had a long and hard look around for documents - I need to retract my comment about single weight oils clinging on longer:

Several different tests seem to conclude that no oil is consistently better than the rest, when it comes adhering to a surface for longer after engine shutdown:

Unless you look at Exxon's website, in which case their product is clearly superior in all tests available

Thanks for the heads-up RW2.

The only real consensus seems to be "run your engine at least once a week, at 165F or more for at least 30 minutes; otherwise corrosion proof it".

I also found a bunch of other documents, all saying to never to turn the engine over by hand in an effort to prevent corrosion.

I do kinda wonder how much is original research, and how much is just the same message proliferating around from one place to the next.

Battson wrote:It would be good to see that study.
The one in this article does tend to agree with you http://www.avweb.com/news/maint/oil_myths_debunked_197096-1.html

Yeah, the study used a similar methodology. And yes, it's limited, but it's something as opposed to conjecture. That's how science works. Theory was straight weight "stuck better". Test was developed. The theory failed that test. Unless another test is developed that validates the theory, or heck even an alternate theory on why humid cabinets in a lab are somehow different from humid environments in an engine, the theory is debunked. One isn't allowed to just ignore the test because the results don't fit the preferred conclusion.

Battson wrote:Yes the conventional wisdom says the opposite http://www.avweb.com/news/maint/182909-1.html?redirected=1

Keeping in mind we're talking about corrosion protection, it's worth noting that a multi-grade oil can absorb more water than a single-weight oil.

That conventional wisdom was published 20 years ago (i.e. before the study) so should be considered to be disproven in the absence of something related to my above note. Please provide background info on multi-grade absorbing more water, I've never heard that and can't think of a chemical pathway for it to be true. In any case, in the cabinet tests it performed no worse than straight weight, so even if it's true it doesn't seem to make a difference. But I am curious to learn more about it.

I totally agree with the "Fly it once a week" recommendation, but I've been told you need to get oil temps up to 180 f for 30 minutes. That's desire able to "cook off" any moisture in the engine or at least as much as possible.

Bear in mind that all fuel contains some water in solution, which comes out as a byproduct of combustion.

I use CamGuard at every oil change. It's cheap insurance, and, even if I intend to fly regularly, oftentimes best intentions just don't happen. Life intervenes, and the plane sits longer than I'd intended.

During those times, it's my hope that CamGuard will help preserve my engine at least somewhat. Considering the cost of an overhaul, a little CamGuard is cheap insurance.

FWIW

MTV

mtv wrote:I use CamGuard at every oil change. It's cheap insurance, and, even if I intend to fly regularly, oftentimes best intentions just don't happen. Life intervenes, and the plane sits longer than I'd intended.

During those times, it's my hope that CamGuard will help preserve my engine at least somewhat. Considering the cost of an overhaul, a little CamGuard is cheap insurance.

Good point. I've been offline for an unplanned month with a kidney stone. I feel better knowing that camguard is in there even though I had planned to fly 20+ hours this month.

Mu comments here apply to automobile engines.

Anyway, years ago I read about owners of expensive blue printed automobile engines. They had installed electric oil pumps, and could crank the engine to circulate the oil without engaging the fuel injection and ignition systems. I am not sure the oil was in anyway preheated, but I suppose that would not be a major challenge.

Anyway, as much as weight is a major concern in aircraft, I am curious if this sort of pre-oiling capability has even been employed in general aviation light aircraft?

@ Nimpocub

Thanks for the link ! That's what makes this such a fab website.

Are any BCP members using this kind of system? if so under what conditions ( Alaska cold weather, etc) , which engines, and any comments re the install in experimental setups?

Tore down a narrow deck 320 a few weeks ago. Overhauled in 1966. Flew less than two months per year in a float equipped PA22 in Fairbanks. Had a bit of corrosion where you'd expect in the cylinders. Two tappets with pitting outside the cam to tappet contact area, cam does have surface corrosion but would run a bit longer. Log book indicates engine is airworthy. Crank measures to near new maximum diameter specs. Half thou under. Rods bushing with two tenths of one thousandths wear. These are splash feed bushings..no pressure feed to the wrist pins. The only part making this engine an accident waiting to happen was the superior heavy wall piston pin. Creating a 5.27 ounce difference in weight between the opposing piston/rod assemblies.
I like the idea of pickling an engine for long term storage. Then pig the engine prior to first rotation with bottom spark plugs removed.
Mark M.

Denali wrote:@ Nimpocub

Thanks for the link ! That's what makes this such a fab website.

Are any BCP members using this kind of system? if so under what conditions ( Alaska cold weather, etc) , which engines, and any comments re the install in experimental setups?

Pre oilers aren't going to help prevent corrosion between flights. They MAY help a LITTLE bit in reducing wear during starts.

But corrosion from sitting is an entirely different topic, really.

MTV