Gummy parts!

[John Beardslee]

I’ve used walnut shells to polish brass, sometimes the media has polishing compound added. I’ve never tried it on aluminum.
Had you tried some other cleaner on the old engine? Or possibly have the engine crankcase filled with some other cleaner that contaminated the antifreeze?

 

[Gary Lauer]

No I didn't use any cleaner. the engine was nice and clean. I just wanted to clean the outside cosmetically, that didn't work to good. John did you use any special antifreeze? I need to find a way to bring it back tp aluminum color. Otherwise I may half to leek for a good block.

 

[John Beardslee]

No special antifreeze, probably was Prestone, straight, never diluted. I first learned of using this process on one of the model helicopter forums, either RunRyder or RC Universe. There was a long thread about using it. I don’t frequent those sites anymore but it might be worth checking them to see if there’s anyone that has had the kind of reaction that you had. What engine is it? I have an old Arden .099 that the block is magnesium, it always gray not bright but I’ve never had to cleaned it with anything but WD40.

 

[Gary Lauer]

it is a OS 18 tz that I want to put in a JAE 12

 

[Gary Lauer]

New update. Today I used simple green and water half and half in the crock pot on another engine. Unfortunately it turned a dark gray almost black. The only common thing between the two cleanings was the crock pot and the temperature. The temp was on high about 200 deg. It looks like I am doing it to hot. The funny thing is that the machined parts were covered with a black substance that came off by scrubbing with clear water.

 

[Bradley Maglinger]

New update. Today I used simple green and water half and half in the crock pot on another engine. Unfortunately it turned a dark gray almost black. The only common thing between the two cleanings was the crock pot and the temperature. The temp was on high about 200 deg. It looks like I am doing it to hot. The funny thing is that the machined parts were covered with a black substance that came off by scrubbing with clear water.

Simple green” D”?

 

[Kez]

I would not put the entire engine into a cleaning solution. Immersing aluminum, brass and steel in contact with each other in an ionic solution will cause galvanic corrosion. I have not looked it up yet but I will bet in this case the aluminum (case) get corroded. It is fine if you disassembled the engine and clean them in the antifreeze.

The discoloration is actually tiny pits on the surface. You can see it with a magnifying glass.

I still prefer to use heat to loosen the parts and disassemble the engine before cleaning the gunk

 

[GraysonTaylor]

From the school of hard knocks: Don't soak overnight in alcohol. Turned my aluminum white with small pits.

 

[Gary Lauer]

the simple green has a D on the label. there was only the aluminum in the crock pot. I got the cases back to nice clean metal by using walnut shells on a vibrating rock polisher.