Compression Test Procedure

Hi Folks,

67 2+2 4.2 engine. To conduct a compression test, I have, in the past, disabled the fuel pump and pulled the cable from the coil. Would there be any problem with simply not turning on the ignition key and using the button, only, to turn the engine and check the compression?


That would work.
Engine is supposed warm, throttles open too.

and all plugs out…

… Battery charger connected…

Pump oiler handy for checking the rings

The engine would not start with the plugs out.

Thank you for all replies!! Much appreciated!!

Still better to disconnect the pump the coil so there’s no spark looking for a way to ground; fuel won’t be sucked in without compression, for me it would add a little safety to run it dry.
And the battery should be in good nick so it doesn’t crank much slower towards the end! Or charger. But not really required.