Different people favor different things; I suspect there's a lot of things that'll work.  I like crock pots, if I can get the motor completely disassembled.  Other people don't, because it can discolor aluminum (I don't care what color my motor is, as long as it pulls my airplanes).  Hopefully folks will weigh in with their favorite goos to use.

What about the blue color on the OS engines?

Bill, I am not sure about the blue OS engines but I know it will remove the blue on some anodized heads. I imagine it would remove the blue on the OS engines also. Someone told me that mixing auto trans fluid and kerosene makes a good penetrating oil. I imagine that Coleman stove fuel would work also. But I have not tried either. It sure would not hurt anything, and with a heat gun should free up most motors.

.... congealed castor oil and castor varnish......

That seems to be two different things requiring two different solutions.

The congealed castor removal has already been well covered but the varnish removal really requires either a mechanical strip down and mechanical clean with something like acetone and a plastic pot scourer or running the engine with some synthetic oil once in a while.

I have a friend who uses only castor based fuels in the air and a synth based fuel at the end of the flying season to clean out the cob webs. Works for him.

Or you sure that you really WANT to remove the varnish from your old engines though?

That seems to be two different things requiring two different solutions.

The congealed castor removal has already been well covered but the varnish removal really requires either a mechanical strip down and mechanical clean with something like acetone and a plastic pot scourer or running the engine with some synthetic oil once in a while.

   Crock pot and antifreeze removes hard-baked varnish almost miraculously well.

    I think we can trust Bill knows whether or not he wants to remove varnish. He's one of the sharpest minds in modeling - in fact, this thread almost seems like an IQ test or a trick question than a real inquiry.

    Brett

No, It's a genuine query. It's just that I typically don't let my own stuff get into the condition that these are in. I am trying to sort out a collection from a modeler who died a few years ago and all his equipment has been in the barn for 6+ years. I have watched the occasional conversation about crock potting and other stuff, but I have used a crock pot on an engine exactly once, many years ago and wanted to see some current thoughts.

Thanks to everyone for the responses, by the way!

No, It's a genuine query. It's just that I typically don't let my own stuff get into the condition that these are in. I am trying to sort out a collection from a modeler who died a few years ago and all his equipment has been in the barn for 6+ years. I have watched the occasional conversation about crock potting and other stuff, but I have used a crock pot on an engine exactly once, many years ago and wanted to see some current thoughts.

Thanks to everyone for the responses, by the way!

Hi Bill,

I was thinking in the same terms as Brett regarding your question about cleaning the engines.  I have had good luck with the crock potting process.  It removes everything, including any varnish that might have built up on the piston.  Some may feel that the piston varnish is good for a well used engine to maintain its seal.

In his Volume 1, 2-Stroke Glow Engines for RC Aircraft, Dave Gierke does not mention anything about the use of a crock pot.  He does have a few paragraphs about removing burned on exterior varnish.  He recommends plugging the exhaust and carb openings with paper towels and then apply "Airborne Hobbies Z-Best engine cleaner to the varnished areas with a stiff-bristle acid brush.  He writes that the Z-Best instructions suggest it takes 1 to 2 hours for the varnish remover to do its work.   Then rinse off with cool tap water using an old tooth brush to help the process.  Sometimes a second application is required.  His photographs show reallying impressing results.

I have not tried this and I do not know if the "Z-Best" stuff is available.  If it can be found, I do not think the credentials of Dave Gierke would need to be questioned.

I personally use the crockpot method.  I use the antifreeze that is made for aluminum motors cause I heard it was the regular that turned the motors black.  I have never had a motor turn black with the aluminum safe stuff and it worked amazingly well.  I made small baskets out of aluminum mesh (like for windows) to put the items in.  Made for an easy retrieval and no burnt fingers!

I never heard if anyone sees a problem with the blue color on the LA 25. I want to drop it in the pot next but I'd rather not screw up the finish on it.

The crock pot and anti-freeze is doing the job well! I have a couple of Fox 35s that were frozen solid that are sweet now! Unfortunately one of the two Enya 35s is really low on compression, the other pretty good. And you should see the DoubleStar 40! What a nice engine!

Bill

My two cents worth....be careful if any of the engines have any hard plastic parts on them (as in a venturi insert - or a wrist pin end plug) the hot antifreeze will melt them.

Thanks, Phil. I think I will try to clean this one with solvents rather than in the pot.

Bill

Bill I did a lot of research on the "crock pot" method and found it to work really well on my Fox and OS 35's but I was strongly warned by an "engine expert" to never remove the cylinder liner from the older OS engines i.e.,  the OS 35S.  I believe that Randy Smith explained to me, that if you take the liner out, it will never align properly again and the engine will be ruined.  I am no "espert" so I trust what Randy and just about anyone else with his credentials has to say about motors.  Just FYI.
Steve Thornton

Hi
It may not ruin all engines, however you can ruin the piston seal by taking them apart, and crockpotting the piston and sl;eeve , then reinstalling them , many times one finds the compression is lower when reassembled, So you pays your money and take your chances.
Also you need to keep fresh antifreeze in the pot, old antifreeze with lots of goop, carbon, oil etc in it will many times stain the motor parts.

Randy

I've been using "Gumout Carb&Choke" spray for years. A little in the venturi and cylinder (remove plug if piston up), wait a few minutes and rock back and forth; almost always loosens up and turns. On the outside, "Dawn Power Dissolver" works wonders, I just limit application time to 30 minutes and don't have a staining problem. Try It, you'll like it.

Al B.

Does this apply to ringed engines?

Yes Chris, even more so than lapped engines, when you take apart a ringed engine the seal will   never.. be as good as it was, and many times it is noticeably less

The best thing to do there is use a new ring, and hone the cylinder lightly, cheap to do and you will have a better engine normally

Randy

 Careful with the oven cleaners   they work but keep a close eye on then don't spray it on & let it set very long. Some are corosive.
  John

To follow up on my original question.....

The story behind the engines: they belonged to a deceased modeler in east Texas. Died in 2007. His daughter was needing to dispose of his modeling stuff and asked if I could take it and perhaps put it to better use than ending up in a dumpster. She was hurting for cash, recent divorce, new baby a few months earlier, etc.... So one day Sandra and I went to her home and brought my pick-up full home.

The engines were all mounted on models except for a couple of Fox 35's and a couple of Enya 35's. Everything was coated in congealed castor oil and dust from hanging in the shop for the past 5+ years.

I used the crock pot and antifreeze on all of the engines except one. All came out beautifully. Even with a 24 hour soak in the pot, a couple were so badly gummed up that I had to use extra heat (monocote heat gun) to get the rods to move on the wrist pin in order to get the rod off the crankshaft. But eventually all came free.

The only engine I did NOT crock pot was the LA 25 since I had heard that the process would remove the blue color. I am sure that blue is some sort of paint since it was flaking off in a few spots. I used heat and solvents to get it apart.

The real good news is that all of the engines went back into the planes they came out of and I offered them and the modeler's supplies to my club, DMAA. A bunch of unused supplies went to the local hobby shop (Mike's, who hosts our club meetings) and the rest for sale.

To say the least, I am VERY PROUD of DMAA! They came through and bought EVERYTHING! What a great bunch of folks. I was able to take a check for $983 to the daughter, and she was floored by it, not expecting anywhere near that amount.

It was a good feeling to be able to help, and I learned a few things about cleaning engines.

Bill

I recently obtained a couple of solidly locked up engines, A Cox Blackwidow, and an AM 25 diesel.  I got them both free and runable with Rislone.  I did have to take the tank off the Blackwidow to free up the reed. There was an amazing amount of crud on the reed.  Generally on a reed engine, if you can get Rislone down the venturi, the reed will almost immediately free up. I have run the engine several times and it is fine.

On the AM 25, I got the piston free enough, with Rislone in the exhaust, and venturi, to take advantage of the sub piston induction and get a healthy dose of Rislone into the case.  In a few minutes this freed up the crank.  I did not disassemble the engine, but let it sit overnight, head down, with Rislone inside the piston, and up against the contrapiston.  Next morning the contrapiston was nice and free. It feels good and I will run it when I get around to it.   

I set my anti freeze bath about the same temp as my hot tub!  I stick a finger in it from time to time just to make sure it isn't too hot.  Anti freeze will work at room temps, but it takes longer.

F.C.

Great story Bill; You and Sandra are the salt of the earth. Great to hear the DMAA bought every thing. It is the people that make great clubs and DMAA is one for sure. Thanks for letting us hear the story. Does my heart good.