Yes, I understand that nitro engines have thermal ignition instead of spark ignition, and I understand the basic factors that control the timing of thermal ignition. I have read about 2-stroke diesel engines too, because they also use thermal ignition, and I have experimented with adjusting the ignition timing on my nitro engines. I just haven't experimented with raising the sleeve, that's why I'm asking for more information about it.

Okay. How much extra timing is likely to be too much? Has anyone ever taken this modification to the extreme to see what the limit is?