Thanks for the feedback again and for the additional waveforms.
I have just been thinking this through further (dangerous I know) looking at the peaks at the point of inlet valve open:
Cyl 1 270 mbar
Cyl2 656 mbar
Cyl 3 449 mbar
Cyl 4 461 mbar
Cylinder 1 being the lowest, I suspect number 1 cylinder inlet valve deformed. However why is there a peak at the point of number 1 inlet valve opening? (Could this be the effects of gas leaking past number 1 inlet valve or has an inlet valve from another cylinder received a kiss from the piston?)
What is interesting is the vacuum pockets too:
Cyl 1 186 mbar
Cyl2 220 mbar
Cyl 3 215 mbar
Cyl 4 193 mbar
Cylinder 1 being the lowest again.
If the engine is not to be dismantled can we do as Rob suggested and look at intake and exhaust pulsations?
It would be nice to remove the head with a couple of images as we can all learn from what we are seeing with the compression waveform.
Take care.....Steve