AFTER RUN OIL
 

Guys, as most of us tend to use after run oil in our engines to help preserve bearings and corrosion, have you ever tried Auto Transmission Fluid as used in motor vehicle automatic tranny,s ? i first started using this fluid when i was racing r/c powerboats just to make sure there was no water in the case area, what we did was after running the engine dry of fuel we then filled the crankcase with auto fluid and made sure the carby vent was closed / pipe blocked / and piston at tdc,beforewe ran the engine again we just inverted the model and turned the engine over slowly by hand and let the fluid run out, all worked fine without any starting problems etc. when you think about this fluid type, its designed as a lube and will not harm any rubber type seals such as the carby seal o-ring or backplate o-ring that many glow engines have. my main reason for this post is to let many know how to keep the engine internals in perfect condition especially if your not using the engine for a while or your using certain synthetic oils in your fuel mix and only adding a few drops of hobby shop after run oil, which to me is both a waiste of time and money.

RE: AFTER RUN OIL
 

Hi,</p>

I think I am doing it even cheaper. In regular flights I use 10-12% Nitro, 18-20% castor and then for the last flight only 20% Aerosave(Graupner's &amp; FUCHS Synth.oil) which cleans up the engine from the Castor's and Nitro's remains.Then roll the engine with starter for about 30-50 sec and drop 20-30 cc of pure Aerosave Oil in the venturi. Then the next flight could be even the next year and no problems at all.</p>

Cheers,</p>

Nikolay</p>

RE: AFTER RUN OIL
 

Auto Transmission Fluid has been used for many years as an after-run oil. I first learn about it from Clarence Lee - probably in the 60s. He also mentioned that many model engine manufactures at that time used it to assemble their engines.</p>

</p>

Paul</p>

RE: AFTER RUN OIL
 

forgot to mention another thing we all did with the boat engines was after running the engine dry of fuel content, we fitted a made up plug that was a glowplug with the center drilled out and then a piece of brass tube inserted and soldered into this drilled hole then a length of fuel tube was fitted to this , running into a container . with the throttle fully open we squirted heaps of auto fluid into the carby vent whilst turning the engine over via a starter, the majority of fluid went out the tube and into the container for later dispossal , this method guaranteed us that the total inside areas of the engines were coated with fluid but we still added more if the engine was to sit for a month or so.

RE: AFTER RUN OIL
 

forget about all that thick after run oil and transmission fluid. go to wal- mart and get rem oil. that remington spray gun oil. the spray oil in the green and yellow spray can. 4 oz size. it's used on firearms,to prevent rust. two stroke engines.......a two second squart in the carb,then flip her over a few times. four strokes a two second shot in the crankcase vent,flip her. will prevent rust in the bearings etc......RON

RE: AFTER RUN OIL
 

Both Rislone and ATF make fine after run oils as will any Air Tool Oil, most all being less expensive than after run oil as sold in the hobby shops. Those spray oils, gun oils, sewing machine oil are not very good, too thin, but better than nothing. Many use Marvel Mystery oil which again is better than nothing but nowhere as good as ATF or Rislone. Also, it requires more than a drop or two or a spray into the carb to do the job. If you do not put in enough to coat the bearings in the crankcase and the con rod bearings, you are just kidding yourself as to the benefits. On four strokes, you must put at least a teaspoon full into the crankcase, not down the carb throat as that will not do much good at all.

RE: AFTER RUN OIL
 

i use marvel mystery oil. but iam sure other oils are good as well

RE: AFTER RUN OIL
 

Castor oil is probably the best after run oil.  And unlike any of the oils mentioned here, it actually mix's with the fuel, allowing the methanol to evaporate so it will not eat up the aluminum.

RE: AFTER RUN OIL
 

I've been using Marvel Mystery air tool oil for several years now. Another positive is that it comes in a small flight box friendly bottle with closable spout. Very quick and easy to use.

RE: AFTER RUN OIL
 

+1 for Sport Pilot's sug.

RE: AFTER RUN OIL
 

I would have to disagree with castor being the best 'after run' oil because it dries out and can cause ball races to skid instead of rolling if left for a long period of time

I would agree that its the best 'run oil' but what we need for after running is -
A presevative that can readily wet all metallic surfaces,
A high detergent in that preservative that can dissolve any 'run' oil and keep it inert and in suspension until its flushed out by the next engine run,
And an oil that doesn't dry out and evaporate.

ATF fits this bill nicely and its cheap as well - it has a very high detergent content and any 'after run' oil should have similar.

Thanks.

RE: AFTER RUN OIL
 

I like Rislone and ATF. Used them for years. Protected the bearings nicely. I now use Prolong SPL100 (an AFMT). Good protection and I like the loose, free, non-gooey feel of the engine even after months of non-use.

Denis

RE: AFTER RUN OIL
 

I have a few engines that havent ran in a year that I ran 50/50 castor/synthetic blended fuel in and they turn over fine. I suppose if you put an engine up for 5 years it might get a little crusty, but a 5 minute soak with some fresh fuel in it would free it right up. I havent used any sort of after-run oil in almost 2 years and dont plan to either. There is just no need - I run all of my engines on a regular basis on all-castor fuel and they all run quite well and have not had to replace any bearings due to rust yet. (knock on wood)

Long long term storage (5yrs or more) I'd use an oil that will mix with castor. I dont see anything petroleum mixing with castor, but I havent tried it either. I know a lot of synthetic oils wont mix with methanol but will they mix with castor?

I might have to experiment a little bit and find out..

RE: AFTER RUN OIL
 

Yes it is the best after run oil, I didn't say it was the best for long term storage. For storage you will not want any fuel in the engine and then you will not need an oil that mix's with the fuel.

Even so I make sure the bearings arerunning smooth before starting.

ATF does not mix with the fuel or the oil. It is also lighter than the fuel and oil, floating on top and trapping the fuel oil mix. The fuel and oil may have dissolved water as well so it may cause rust or aluminum oxidation.

RE: AFTER RUN OIL
 

Which ATF - Dextron II or Type F?? ;)

Castor - nope - it gums up pretty fast. F2D fliers flush all the castor they can out of the engine at the end of a flying session - the problem is it causes bearings to skid upon startup at the next contest. SOP is to fill the muffler with gasoline and set the models on the rack nose down. Then oil with an after-run oil.

Marvel Air Tool Oil - yes, but NOT Marvel Mystery Oil. The latter can freeze an engine solid if left alone for a few months. I have heard that Marvel Air Tool Oil has ignition inhibitors in it (remember its original use) so it can make engines a little harder to start on the first flight of the day, and I've heard that it is especially not recommended as an after-run for model diesels for this reason.

Iskandar

RE: AFTER RUN OIL
 

I have a few engines that havent ran in a year that I used my homebrew all-castor fuel in and they turn over smooth as butter. I wouldnt use any petroleum based lubricant as an afterrun oil simply because petroleum oils do not stick to metal as well as castor IMO. Moreover, old gummy castor oil will easily re-dissolve in a little fresh fuel or even pure alcohol. I dont use after run oil anyway as the castor film does a great job of protecting the engine. If I were to store an engine for a period of time longer than 1 year, I would use something else. Perhaps mineral oil or something else thats non petroleum based. Ive never had an engine sit longer than a year so I havent had the need for extended storage maintenance. Granted I have only been in the hobby for about 14-15 years now I havent got the knowledge base that others do so I am only posting from my own experience.

RE: AFTER RUN OIL
 

That's not gum but dried castor oil.  And as it covers the parts ahd hardens it protects them.  You get rid of it by heating or soaking in fuel or methanol.  However as an after run it won't usually be in the engine long enought to harden.  If you plan to store the engine you can flush it out with fuel or metanol, dry it out, and use a good mineral oil.  But not MMO or WD40 as those have solvents which will dry out.

RE: AFTER RUN OIL
 

OK for a plain bearing engine, perhaps, but not something you even want to consider for a racing engine with ball bearings. The gum um, gums up the balls in the bearings (especially the rear one) and then you get balls skidding at startup.

Come to think of it, for very long term storage, one well-known person I know stores his engines submerged in a paint can full of kerosene.

Iskandar

RE: AFTER RUN OIL
 

I just cannot grasp the idea of submerging or soaking a model engine with rubber seals, gaskets, and o-rings in any sort of petroleum distillates of any sort. Whether it be ATF, MMO, regular ARO, kerosene, etc. It is well known that petroleum products swell rubber parts. Plant based mineral oils seem to me to be the obvious choice simply because they don't have petroleum chemicals in them to cause damage to the seals or the bearings. I'm not going to say petrochemicals will for sure cause damage, but I will not chance it personally.

Castor oil may solidify and crud up the bearings some, but if you take the time to flush/soak the engine before running it would and could make all the difference. You wouldn't take your classic musclecar that's sat for 5 years and just go drive it without at least changing the oil and priming the oil system before firing it.

Just common sense to me. Again, I'm not saying petrochemicals will for sure cause damage, but I wouldn't risk it. New engine or old, I don't want to have to tear the thing down and rebuild it before I run it. I am confident one wouldn't need to if stored with a degummed/glycerin-free plant based oil. Just IMHO.

RE: AFTER RUN OIL
 

Fox Combat Specials don't contain rubber parts.

Iskandar

RE: AFTER RUN OIL
 

I just run my engines dry, and that's the end of it. When they stop working because there's nothing left in the tank, I put them at BDC and stash them, I do nothing more. Haven't had a speck of rust in any of them, and they never fight me on restart. I also don't have to screw with air filters, and I don't have to pour stuff into a tiny-ass little carb.


I do turn them over at least once a month, though. One or two slow pulls for the cars, for my plane I'll just flip the prop a couple times.


I do, however, use Dexron III ATF as an air filter oil, so car guys at least should have a quart on hand.

RE: AFTER RUN OIL
 

I'd been looking for Marvel air tool oil - fairly hard to find around here, and when I did come across some some years back it was quite expensive. But today I found, at the Ace Hardware, Ace Brand Pneumatic Tool Oil. Price was reasonable. I suppose I should give it a try. I've heard air tool oil has ignition inhibitors in it, though. Hmmm..

Iskandar

RE: AFTER RUN OIL
 

IMO, I wouldnt use anything petroleum in a model engine. Main reason is it wont mix with glow fuel so when you plan to run it it would probably need to be flushed out first.

I just pulled the backplate off my TT .46 that I've ran on 5% nitro 20% castor for almost a gallon. Everything inside looks just like it did when I got it. It was a 15yr old NIB engine that already had a few rust specs on the crank counterweight from sitting for 15yrs. Now its got a nice film of castor all over it and hasnt gotten any worse. I run my engines out of fuel at the end of the day and pull the fuel line at the carb when its sitting.

I also turn my engines to BDC after I'm done running.

No need to use any storage oil or after-run oil if you run it dry and use fuel with castor. The castor might congeal and thicken after awhile but a little squirt of fuel and flicking the prop a few times works wonders for getting it turning easy again.

RE: AFTER RUN OIL
 

Isn't the point of using ATF the fact that it will spread over any metal surface all on its own? I give my engines a shot of it at the end of a flying session, but I don't spin them afterwards as the OP suggested. For one, that causes wear on the piston and sleeve for nothing, and two if the engine will spin with the starter it doesn't have enough oil in it to do any good. I pour the carburetor full and hand flip a couple of times, then store the planes nose down.

That said, the most important thing by far is to run the engines completely out of fuel and let them get hot in the process. Whatever water and alcohol that is left inside will mostly evaporate if we do that, reducing the need for rust protection in the first place.

RE: AFTER RUN OIL
 

Sea Foam in the aerosol can and straw. One small shot down the carb into the crankcase with the passages open and it foams out, nothing inside the engine can escape it. You might find it a little messy but the film goes right to the metal and stays there. It displaces any moisture. Try it sometime, I like it.

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