Originally Posted by
JieM
Not sure this engine has a high compression ratio. Has anyone ever measured it? Otherwise I would do it the next time this engine is on the bench. Remember that the valve blocked in open position did not touch the piston. So there is still some room...
But the issue of detonation is in my opinion rather related to the too important timing (up to 52 ° before TDC on 1 cylinder) on this engine.
JM
Why is your ignition timing so far advanced? I use 35 degrees BTDC with methanol. 52 degrees BTDC is at least 20 degree to far advanced for gasoline.
And why are you citing #1 cylinder? Are you under the impression that the ignition timing varies significantly from cylinder to cylinder?
If you think there is a significant variance of timing between cylinders, where could you have possibly gotten that idea?