Discussion in 'E46 M3 (2001-2006)' started by crossie, Aug 13, 2018.
You need a 12mm adapter.
Dont use the long laser one though. See thread below for details.
Pretty sure I have the adapter folk said not to use and "it works on mine"
Also remember that the pressure release / non return valve on the tester is further away from the cylinder head than it would be when directly connected
This means that the volume of the adapter and the pipe effectively is added to the combustion chamber volume which lowers the reading.
If you subscribe to the "5 cranks" theory you may well get a lower reading than cranking until a stable reading is reached which is how I would do it