When doing the piston ring test of putting kerosene in the cylinder to see if it leaks by the rings after 15min. no leak by but over an hour later it did .Are the rings good?

Answer 1

That was a good test if you had a Model T Ford. Using kerosene washes all the oil away from the piston, piston rings and cylinder walls. Not a good idea during start up. These days we use a compression gauge. Take a compression reading of all cylinders with spark plugs out, coil(s) and fuel injectors disconnected. If the first compression reading on a cylinder comes up low, squirt some motor oil into the cylinder and take a second reading. If the reading doesn't change much you have bad valves. If the reading goes up substantially you have worn/cracked rings. What you want to see is all the cylinders having a reading within 15% of the highest and lowest readings.