I want to test my combustion chambers for percentage leak down and
have a gauge tool on the way to accomplish that.  My question is
whether I have to have a real air compressor to do the testing?  I
have  a air tank I can take to a gas stationand fill it to 120 psi
safely,and am wondering if that is adequate?  Might have to make more
than one trip to finish all 4 cylinders, but my only other
alternative is to use an electrical tire pump from Campbell Hausfield
and try to fill the combustion chamber that way. Since the pistons
will be at top dead center, I would think that the volume of air
needed would be minimal; like under 200ccs, but I could be
wrong.  Probably not a bad idea to lock the crank too.  Will report
findings when the job is done.

Thanks

DM&FS