I imagine that my hvac vacuum pump and micron gauge setup is overkill. We use these for pulling deeeep vacuum to evaporate any water molocules inside an AC system before we put refrigerant into it. What is probably necessary is a vacuum gauge used to test automotive vacuum systems... Something that measures in inches of water column.. Not microns.
If I hooked one of my pumps to a tight engine, it would probably damage the suction lip on the crank bearing seals.
Hopefully a builder on here can clear this up.
How many inches of vac. And for how long? I would like to know for my current rebuild.