Did you state that your calculated compression ratio was 20:1? That is what I gleaned from the info. That sounds way to high for a model Diesel engine, but more inline with what full size Diesel engines utilize.
I removed the new head after running the engine. According to my calculations, the compression ratio is now about 1:12
There is one thing I still find strange though;
As I understand it, most people state that a converted methanol-engine's carburettor should be set to about 60% open at full throttle to get a correct fuel mixture. Even better would be to exchange it for one with a smaller bore, because the smaller venturi makes it easier for the engine to suck the fuel out of the tank.
But what happens if the original carburettor is still set to open 100% at full throttle? Should the engine die, because it gets flooded with fuel?
I still have the original carb on my engine and I still can get it to run at wide open throttle, but only if I open the main needle up about 3 turns (if I don't do this, it will just stall)
Should I be able to get the same RPM and power with the carb only opened 60% and the main needle closed down?
What seems the most logical thing to me is, that if the engine is getting more fuel/air mixture and still can run at full RPM, it should be making more power. At least, that's what people try to establish when tuning a full-size engine. The problem with trying to burn more mixture would be getting it to burn at all (e.g. increasing compression an thus increasing engine-temperature, which can lead to detonation if taken too far)
Any ideas?
Cyril