I ravaged the saw I posted about earlier. I learned something. A Saws-All is great for paring down the case. I had been using bandsaws. Those blades are expensive. Once you touch steel they are toast. The engine pared down very nicely. This thing is extremely minimal. The remnants of the case is very light and compact. Looking at is, it is 80% jug. I think I will also pare down the cooling fins. They seem huge. I envision a rotary table and a milling machine to do the neatly. How do guys normally do this?

The only questionable thing is the piston. It is scored, a little, on the exhaust side. The rings look unharmed. In fact the rings are still blued. They are not even worn shiny. I am thinking this one was a victim of straight gas. The rings are stuck, for now. The jug looks good. There are a few little bits of aluminum galled to the jug below the exhaust port. That sould clean off with some steel wool and oil. The bearings are full of junk. They seem smooth though. The inside is really filthy. They guy who had it, must have left it in one of his trash can full of engine and wacker parts. He said the cans would sweat inside. Most everyting I got form him is oxidized from this misadventure. He lives about one mile from the ocean.

My plan is to stick the pieces in an ultrasonic cleaner intended for firearms and see what happens. I'm really hoping to get this one working. It is rated a 6hp from the manufacturer. Maybe I can do better? 40# of thrust sounds interesting.

How about the scoring on the piston? It is not obscene but is significant. How much does it matter if the rings are good?

" How about the scoring on the piston? It is not obscene but is significant. How much does it matter if the rings are good? "

If scoring is above the exhaust on the cylinder, it makes a big difference.

The piston not so much, have it glass beaded.
New rings from [email protected], always make a big difference.

His rings seal by fit not tension.

Ralph,

What do you mean the rings seal by fit?

These rings seal by fit. They do not rely on ring tension.
There is no end gap, so they seal better.

I know from personal experience Bowman rings are just better.

I believe they are $12.00 shipped.

http://www.rcuniverse.com/forum/m_91..._1/key_/tm.htm

The firearms parts sonicator worked out good. The jug sonicated real nice. The galled on aluminum came off the inside of the jug. I can see streaks but can not feel them.

I found piston and ring kits for about $30. I'll see if he has bearings while I am at it.

Here is the bigger question. I am doing this partly for entertainment value and partly for more power. I did an Echo 650 a while back. The target airplane is now running a BME 50 clone, It flies fine. The 650 was perhaps a little faster but not significantly so. It is floatier with the BME. It is harder to fly in the wind wih the 50. The extra weight offset some of the gains for all around performance with the 650. Will I make enough more power with this, to nottice, with this engine?