This OKAY for engine cleaning

That's some mean stuff you bought, but it will definitely melt plastic. I agree, denatured alcohol is cheap, safe and easy.

I do it the old fashioned way.  I just toss the parts, or the whole engine if it's too gummed up to disassemble, into a glass jar with some glow fuel.  Let it sit for a couple of hours and then disassemble and clean.  If it's not cooperating, let it sit for a couple more hours.  I know the glow fuel won't eat the plastic, and it's never failed me yet to get the engines to turn free and shine up if I use a tooth brush.

The Olden Days Mark

Thanks everyone for the helpful suggestions. I ended up returning the over-the-top paint stripper for simple denatured alcohol. Left it to soak over a long weekend (4 days).

When we returned, my son and I spent some quality time on the back porch cleaning up the parts and re-assembling. The alky worked great! It's a nice older Medallion .049 with throttle ring and now that it's cleaned up and well lubed, compression and hand turnover feel really good. I'm a little concerned about the amount of slop in the crank/drivenut play (I don't think I have the drivenut fully seated). I pushed it on by simply screwing in the prop screw with a prop on.

Any suggestions for a better way?

Next up, building the ultimate test stand, thanks to bernie at Cox Int.!

Did it have one of these? Even then sometimes due to wear or poor prodution quality you may not be able to get it to seat properly.
http://www.ebay.com/itm/3x-Cox-049-051-Tee-Dee-Model-Engine-Thrust-Washer-049-051-Phenolic-/390370583268?pt=Radio_Control_Parts_Accessories&hash=item5ae3e662e4

No, no thrust washer. I didn't think Medallion engines ever had these as a standard part. I may end up getting some of these, but I don't really use electric starters.
 
I have seen someone on the online auction house shilling a tool for setting the driveplate. It just looks like a prop screw with a second nut for tightening it down onto the crank, but I'm not sure how it holds the crank firm to keep it from spinning backwards.
 
I have a newer medallion .049 with a throttle muffler, rather than the throttle ring. It has a lot less play, but there is still some (no thrust washer there, either).

The washer is just a easy fix if it is really needed. There should be a little play up front. . The piston is held in place by placing a Cox tool in the exhaust port to keep it from moving. The tool you are takling about in my opinion is not really needed A Cox tool, prop, washer and screw will do the same thing for free. Same with the Cox drive plate remover. One can be made from parts from a hardware store for a fraction of the cost. A good tool to have is a Cox piston reset tool. They are worth every penny.

Thanks, batjac. I have the reset tool for both my 049's and my 020.

As for the Cox tool in the exhaust port to hold the crank still, I'd be afraid of warping or damaging the piston skirt this way. I havent tried adding any washers in with the prop. Maybe I'm bottoming out the prop screw in the crank. I'll have to give that a try.

Then use a shaved down popsicle stick.

VUgearhead wrote:Thanks, batjac. I have the reset tool for both my 049's and my 020.

As for the Cox tool in the exhaust port to hold the crank still, I'd be afraid of warping or damaging the piston skirt this way. I havent tried adding any washers in with the prop. Maybe I'm bottoming out the prop screw in the crank. I'll have to give that a try.

I've never actually done this, but surely the tool in the exhaust port rests on the piston crown.  By ensuring that the tool goes all the way through and out the other side would keep it flat and ensure no damage to the piston. You'd surely have some serious SPI if you could get a tool in the port and underneath the piston.