Originally Posted by etap
I am almost sure that it don't reach compression until it is running.THX
Even with an ACR...you should have 100 to 120 psi...
Did you continue to crank the engine until the gauge stopped climbing..
With almost 400 hrs on the engine it would probably be a good idea to check and adjust the valves..
Patriots suggestion may help diagnose any ring issues..
What compelled you to check the compression...????