Big thumbs up for all the effort you have put in to trying to find the cause of this problem, sterling effort much more than I could or would have done but is now not time to stick it on a flatbed and send it to one of the respected Indies. Their knowledge and skill should identify the problem quickly and then you can decide on the best way forward.
Valve timing would not allow gas/oil into the wrong place, which is what you have. And as your compression tests seemed ok then valves and rings seem ok.They vary the valve timing. Seems very unlikely to me.
C
Have just had a very long conversation with Mike Roberts from the Maserati shed about this today, and he has suggested a course of action to try and diagnose the problem, although it is a new one to him, I think with his expert input I will find a conclusion to this problem, He has a very analytical mind, and has suggested a few procedures to do as a start. Very interestingly, he rates the 3200 as a far superior car to the 4200, in terms of both build quality and reliability! ( that should start the debate going again!)
?? Having owned both (and liking both for their different driving experiences) this is absolute nonsense!
Having driven 4200's lots of times and owned a late 3200GT for nearly 9 years
The 4200 CC cars are a lot easer to live with on a everyday basis than a manual 3200, period!
On the other hand for a hooligan week end car, you need to learn how to drive them though, the 3200GT is on another planet!
I used to run mine down to southern Europe regularly, there was nothing to touch it at the time, you could run at 150 or so for 15 minutes at a time though Germany, rock steady and in near silence..
It was and still is a fantastic old Maser!
Dave
Having driven 4200's lots of times and owned a late 3200GT for nearly 9 years
The 4200 CC cars are a lot easer to live with on a everyday basis than a manual 3200, period!
On the other hand for a hooligan week end car, you need to learn how to drive them though, the 3200GT is on another planet!
I used to run mine down to southern Europe regularly, there was nothing to touch it at the time, you could run at 150 or so for 15 minutes at a time though Germany, rock steady and in near silence..
It was and still is a fantastic old Maser!
Dave
Quite agree Dave though I think the Gransport is pretty special. It was the reliability and build quality part that made me choke on my vino rosso!
What happened after 15 minutes ?
Did a Cel come on !