M103 compression specs
Not sure if MB published a range like they did for the four cylinders ( 147-176PSI ), but they indicate a minimum of 8.5 bar / 125PSI with a max variance between cylinders of 1.5 bar / 22.0PSI.
Prior to my turbo install we had 12.9 bar / 190 PSI with less then a 5 PSI variance betwen cylinders.
This was on a well maintained 1988 M103-12V with 63K miles.




