Hi,

This thread may belong in the Crash & Rebuild section but I thought some Beginners would benefit from the responses.

What method would you use to clean a Engine that was completey muddy,dirty due to say to a Crash but can be restored?

My method is to remove the backplate, head body carberator and all the rest of the parts and clean them in pure ANTIFREEZE
using a soft brush and gloves. After several batches of soaking/cleaning. I Lubricate with Marvel Mystery oil.

A couple of other things.

DO NOT TURN THE ENGINE OVER !!! Doing this has an excellent chance of scoring the cylinder.

If you do not want to completely disassemble the crashed engine, after removing backplate, carb and head, THOROUGHLY flush the engine with fresh fuel to get rid of any dirt. Pay particular attention to the crankshaft/bearing areas. When done, reassemble the engine and run it. If you can't run the engine, pickle it in Marvel Mystery oil (or air tool oil or after run oil ) until you can run it.

There's a comprehensive article on http://www.masportaviator.com on that very subject.

For just cleaning off dirt, debris, grease, etc. I have always used some old fuel. Then I wash it with soap/water, dry thoroughly, and work in plenty of light oil. I have never tried antifreeze. I have heard that you can get the baked-on varnish off by cooking your engine parts in a crockpot with antifreeze (BUT NEVER use the crockpot again for FOOD!).

But is antifreeze harmful to plastic and rubber parts? I've heard both ways...

The best method I have heard for cleaning the exterior of engines is to spray with Dawn Power Dissolver, let sit a few minutes, then scrub with an old toothbrush.
You don't have to take it apart, don't need a crock-pot that you can only use for this purpose, and you don't need any antifreeze (which has it's own concerns).

If the engine has been in a crash, the first part I remove is the carb. This lets me look to see if the dirt got down to the crankshaft or not. If it didn't get to the crankshaft, there's no need for any more disassembly. If it did get down that far, I will usually do a complete disassembly so I can be sure I can remove all of the dirt. I use rubbing or denatured alcohol for cleaning.