I have the parts for an OS FS48 4-stroke glow engine. The engine was running fine, but the airplane didn't. The fatal landing cracked the crankcase of the engine, but did no other apparent damage.
Here are all the parts as shown in the picture. I carefully disassembled the engine and bagged the parts. Upon doing that I discovered a couple other unfortunate things.
The crank pin is broken off and the piston skirt has a slight crack at the bottom. The ring, piston pin, and cylinder liner are in good shape. Everything else looks good, too.
Looking at the parts lists on the OS website indicates most of these parts, except the crankshaft and camshaft, also fit the FS-52 engine. I didn't look at the listing for the FS-40, but I'm betting the parts would fit it, too.
I checked prices for new replacement parts on eBay. Adding all the lowest priced parts I could find totaled over $140.00. I'm not asking anywhere near that for these bags of parts.