The 50-50 22% oil sounds good.  You might consider the antifreeze crock pot.

         
     Hi Pete and Ty:

     I checked the engine in question and sure enough, the entire combustion chamber was black with? The inside of the head was also very black.  The sides of the piston was brown with a very right piston ring easily visible.

     Now this leads to additional questions:

      Should I Continue using the 5%-29% castor fuel?

      Should I change to a different fuel?

      Should I crock pot the engine?

      Should I not change anything and not alter an engine that is performing perfectly?

      OMG Ty. I don’t know how to respond to your comment about thinking about you while I am having sex with my wife? Lol How long were you aboard long lonely cruises? LOL

       Thanks for the replies.9
                                                                                      Frank McCune

You didn't tell us how much running time you have on it since last cleaned. If you have a lot of time on it, I would consider this normal for using 5/29 fuel.

Changing to 10/11/11 fuel would minimize this.

Crock pot cleaning using antifreeze is the least damaging, or least potentially damaging way to clean things. You already have it apart, so do it now.

I would not use steel wool on any of the parts. Shouldn't be necessary, and getting strands lost inside the engine if you don't get the parts clean is not going to improve the run....

The antifreeze will remove carbon buildup, but may take a few days. The worst I've seen were a set of Fox engines I rebuilt for a guy we can call Al Carbone. I cooked those guys for at least three or four days but they all came out clean. If your liner is still black after the carbon comes off, that suggests it is a temperature-induced discoloration. That's a different deal, and you're going to put the parts back together, regardless. Just for info, if the color change is truly "black," that indicates a temperature somewhere around 550F to 600F. I would expect the combustion chamber temp (at the top, near the head) can get into the mid-five hundreds, so that is not proof of overheating to me. The fact that the liner "fell out" suggests that the heat transfer from the chamber walls to the case is poor, meaning that the liner will get hotter and discolor more than one with what I would call a proper fit. I am not a fan of dressing the bore of the case so that the liner floats, for just this reason. Other guys insist that they relieve the case bore to keep from distorting the liner and screwing up the running fits. My preference is to find parts that are actually well machined, straight, cylindrical, etc. so that "rework" to loosen the fit is not needed. This brings me to a related point...

If it ran really good before on 5/29 fuel, and there is a loose liner-to-case fit, I would be very careful about going down in oil content or substituting to a high percentage of synthetic oil. The concern being that you are likely running the liner hot, and doing anything that allows that temp to go higher is not going to be helpful. Better to run a hundred flights with a castor-heavy mix and then dunk the entire assembled engine in the crock pot. Also, letting the crud build up on the outside of the engine is another way to cause heat to build up. After each session, spray it off with cleaner.

I wouldn't worry about having to "break the engine in again" if it is properly reassembled. If the parts are good, there's no reason it shouldn't go back together and run the same. If you have trouble getting it to run the same, then either your methods are not proper, or the parts fit was not good to begin with. Top of the list for improper methods would be damage to the liner trying to get it out. Since this one "fell out" inadvertently, I suspect that means it was not grabbed with the nearest pair of pliers. Next, if the engine is assembled with crud under a sleeve flange or in the head land and the screws torqued down, causing things to warp. Next, the ring is somehow abused trying to either get it off, get it on, or simply get it back into the sleeve. Don't take the ring off! Or, if your engine has ball bearings, all kinds of ways to snarf that up by improper disassembly/reassembly. The outcome is all some variation of "it doesn't run like it used to."

Good luck with your engine. Hpoe you get it back together and running as well as it used to,

Dave

Re. Al,  My sediments exactly!

     Hi:

      Thanks for all of the replies.

       Your comments agree with my thoughts.  I have reassembled the engine and will run it on a test stand when I get some extra time.  I have not removed any “black stuff” as I am convinced that it may be a good thing.  With a ringed engine, I am concerned that the black stuff may be interfering with the proper action of the ring.

         It has been suggested that an all castor oil lube will foul a piston.  This can be avoided by adding a portion of synthetic oil to the mix.  Perhaps I should switch to a 5-11-11 in the future to avoid any further buildup on this older engine.

          I have been advised to use a fuel with a very high percentage of caster oil in these older iron/steel engines.   Due to the ring, I may try the 5-11-11 mix .  After all, the engine will be run as a 4-2-4 stunt engine.  How much stress and wear will this engine have to endure in this mode of operation? Sounds like easy duty to me.

            Suggestions/comments?

                                                                                  Have a Cool Yule and Frantic First,


                                                                                   Frank McCune

Experiences vary.  In my case, I like the look of my silver OS LA .46 after the crockpot antifreeze treatment.  Plus, it had so much castor oil varnish on the cylinder/piston that it squeaked.  The varnish was maybe 1/16" thick in the head. Switching away from 29% castor fuel seems to have helped, as I now run half synthetic, half castor with total oil 20% or 22%.  I noticed no loss of compression, though I agree the ringed technology is different.  Castor in the ring lands would be a concern, as well. Stuck rings happen.