Well folks, I reassembled my OS.46FXH with my nice new bearings and the custom piston and liner set and she runs like a dream. I stuck a 10.5x6 Bolly Clubman prop on it, bolted it to my test stand (read: plank of wood with a notch cut in the end) and fired it up. It fired up with no problems and seems to run just as nicely as the ringed arrangement did, even considering I've halved the nitro content in the fuel now. For some reason, it requires much leaner needle settings than it did with the ringed piston and liner. I this normal for an AAC arrangement, or is it just because of the much lower nitro content?

Here's a pic of the custom piston and liner set.

It is the lower Nitro that causes your engine to run leaner. Nothing to do with the AAC setup.

Ed S

As Ed said, it's the lower nitro. As I remember it you were going to change from 20% nitro to 10% which means your methanol content went up by 10%. Nitro needs an extremely rich setting (air/fuel ratio) compared to methanol. Just curious but did Ranjit alter the port timings?

Not as far as I know. The guy I got this set from (Frank Harrod) was talking to Ranj about them.....apparently they're timed the same as the standard OS items.