Originally Posted by
ralphierace13
never mess with shim unless u changing nitro content to match, when u change shim u change the detonation burn on the top of the piston, the burn explosion in our motors burns from the center of the piston outwards if u change the shims and leave the same nitro then it no longer will burn from center out and that's when people get the top of there piston looks like its deteriorating, it eats away at the top of the piston
Exactly that's my point. Novarossi's come from the factory set at 16% nitro as we run in europe. Some of the latest engines also come with a different head button for use with 25%+ nitro. So if you are running 25% nitro and running the engine out the box that maybe why you are blowing plugs so easily and so adding the 0.1mm shim would help. I mean even if I get the top end a fraction lean I still don't blow the plug - sure I change it as a precaution if the element looks a bit dry or grey but I don't usually blow the plug.
Anyway we probably shouldn't be hijacking Rody's thread discussing Novarossi's! Best to continue debating about this if we want over on the Novarossi thread. Sorry Rody!!