AV8tor,

That's encouraging. Looks like the CR for glow is about the same for gas. I note though, with a little research that an ethanol gas (E85 for your car) raises the octane rating. That doesn't mean more power, just the reduced chance of detonation. E85 with premium gas is said to have an octane rating of 105.

So when we go to a gas glow mix, especially in the proportions recommend, we are REALLY boosting the octane rating. But how much? This, to me implies that we should be going to a higher compression ratio when converting to a heavy gas/glow mix. However, this is compensated for by the presence of the glow plug and methanol, I presume.

The catalytic effect of the glow on the methanol does it;s job and ignites the methanol, then the gas at the same timing as pure glow fuel. Somehow it works as we've seen here many times.

The reason for this line of enquiry is that I'm at the stage of making the heads for the Tanaka. Tanaka advised that the stock engine had a 7.5/1 compression ratio and that's about in line with most. And, research shows that that matches about what glow engines use.

THEN I stumbled on the O'Neill Brothers website and was surprised at the CRs they list. Much higher. They also seem to have some real kick butt engines in their line which seem to operate at those CRs just fine. And look, Zenoah upgrades.

Has anyone ventured to do a gasser conversion using one of their engines? I'm especially intrigued with their bolt on heads and "stuffed" cranks. And look, a bolt on reed kit with carbon reeds. And they offer ported, polished and timed engines done by hand. Too much. Gonna call them tomorrow.