after run oil for model airplane engine

[MRC01]

I just finished rebuilding a couple of model airplane engines that were so gunked up with varnish they could barely turn. In order to avoid having to do this in the future I was wondering if there is an after run oil I could use to reduce or eliminate this.

The engine burns glow fuel: approximately 25% oil, 10% nitro and 65% methanol.

The ideal after run oil would likely have a low viscosity with an additive package designed to clean out the engine and eliminate residue. But also to burn clean for the next time the engine is used.

Any specific recommendations? Would ATF work? And due to the requirement for the after run oil to burn clean, are synthetics still viable?

 

[wileyE]

Not sure what your running for oil now but many of the rc oils are castor based which may be the source of your gunk, besides just the shear volume of oil in the premix leaves a lot of oil behind. There are castor free synthetics available from many of the specialty blenders like klotz, torco, spectro etc. Just be certain they are safe for ni and meth fuels.

 

[MRC01]

Most of the glow fuels these days are not pure castor oil, but either a synthetic/castor blend or pure synthetic. But over time they all gunk up the engine if after run oil is not used.

My question is who makes a good after run oil? I see them in Tower Hobbies for a buck an ounce which seems ridiculously expensive. Common sense says it's just a low viscosity oil with an "appropriate" additive package. Are there any oils available at the local auto parts store that will do just as good a job? It's basically just an engine flush to eliminate residue.

That's why I was thinking ATF might do the job because it's fairly low viscosity with dispersants in the additive package.

 

[wileyE]

The stuff like blue-block I think is more to "pickle" the motor for storage than it is to clean oil residue. Anything run on meth needs this attention or you get corrosion. Guys I know that race quads on fuel just run some gasoline premix through them before they put them away.

 

[Brett Miller]

Marine fogging oil will work well.

 

[04SpecV]

What about using Marvel Mystery oil (MMO) ?

 

[MRC01]

Thanks for the tips. Has anyone tried ATF as an after run oil?

 

[Drew]

I have used the following products successfully either alone or mixed with each other in my model airplanes:

1. ATF: Tower hobby sells this stuff in a small white bottle for 3 bucks but doesn't call it ATF. Huge markup. I don't use ATF much anymore because I don't care for the smell.

2. Air Tool Oil is great and comes in a convenient bottle at an affordable price at Walmart.

3. Marvel Mystery Oil also works great but I don't care for its smell.

So far, I've been using air tool oil for the past 3 years and have never had a problem with rusty bearings.

PS Do not use WD40 in any used engine. It will strip any light oxidation in your engine and free up the sandpaper like oxides to scour your cylinder

Also, your best best us to use a blended fuel with at least 5% castor and then you can worry less about afterrun oil.

 

[MRC01]

quote:

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Originally posted by Drew:
Also, your best best us to use a blended fuel with at least 5% castor and then you can worry less about afterrun oil.[/QB]

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Thanks for the tips. In the past I always ran some motor oil through the engines at the end of the day but I never tried an oil with dispersants or other additives specifically designed to flush residues.

By 5% castor you mean a fuel with 20-25% total oil content, of which at least 5% is true castor oil? I've tried fuels with true castor and synthetics. Over time they all gunk up. True castor may gunk up less but honestly I never noticed a difference.

These 2 engines are OS Wankels and I use the fuel recommended by OS. That is 25% oil with 5-10% nitro. The slightly higher oil content is what is commonly sold as "4 stroke" glow fuel. That said, I've noticed the same gradual gunk up issues with my boingers too - so it's not just a Wankel thing.

 

[ccs79]

I bought the Tower Hobbies after run oil for use in my monster truck engine. The stuff in the small expensive bottle looks and smells just like Marvel Mystery Oil. It works well, especially for extended storage.

 

[LarryL]

I use WD-40. Spray it on/in the engine and turn it over a with my electric starter, then put it away, after cleaning the fuel tank and line.

 

[Cujet]

I know this is not the same thing, but I use TriFlow spray oil on everything that needs short term corrosion protection. In our corporate flight department, we operate 2 helicopters EC-135's and 6 other aircraft. The TriFlow is thick enough to provide protection, yet remains gunk free. It works especially well on our Extra 300's to prevent corrosion, both inside and outside the engine.

We use all sorts of other products for corrosion protection, but I believe TriFlow may be worth considering for your uses. I am assuming you can spray it into the engine after use. I do this with the Extra's at the end of the season, with good results.

Chris

 

[Propflux01]

Long ago, I used 3M 3-in-1 oil. MMO works just as well, just (to me) alittle harder to deal with than 3-in-1, because teh 3-in-1 has the little tiny spout on it. I think both do the job well.