If you want a plain-bearing 40-sized engine that's streets better than the OSLA, look at the Thunder Tiger GP42. Our club has one of these on its trainer and it's a stunning little engine. This one was bought new for $49 and has vastly more power than the 40LA, it also idles like a dream, transitions beautifully and is tough as nails.

There are fins missing off the head on ours because it smacked into the tarmac runway inverted (at speed) -- but it still runs. It's also been siezed once (don't try using 30% nitro fuel :-) but, despite this it has excellent compression and retains its good manners and power.

As others have said though, a TT46Pro is perhaps the best value 40-46 sized engine out there right now. You can buy them for $74 (little more than the OS40LA) but they produce way more power and, once the trainer gets boring, can be moved into far more capable aircraft and still provide sparkling performance.

My oldest TT46Pro has now done about 220 hours and still runs almost as strong as when new.

The 46Pro will give you everything you'll get from an OS46AX but at a far lower price (I've now got four of them :-)