This is great for checking rings but you neglected to address the valve seats or the head gasket. For instance, if you hear air coming out the valve cover oil filler neck/oil dip stick, then that is rings. If you hear air coming out the exhaust, then that is an exhaust valve issue (bent valve/carbon build up on valve/seat, worn seat/valve, etc...). If it's coming out the air intake, then an intake valve issue. And if your hear air or see air bubbles in the cooling system, then a head gasket issue. You can also check to see if you hear air coming out the adjacent cylinder(s) spark plug holes for head gasket or large cylinder wall crack/hole. I just did a leak down on an engine and saw this very issue. Pressure in cylinder 1 with air coming out the exhaust, plugged the exhaust and then got air out cylinder 2 spark plug hole..... NO BUENO
Yes, part of the system analysis… add oil to the cylinder to rule out the rings… then tap on the valves to confirm they are seating / sealing (oh, don’t forget to evac the oil before replacing the spark plug)
Awesome video, gents!
A great explanation of a useful test procedure. Nice one 👍🏻
This is great for checking rings but you neglected to address the valve seats or the head gasket. For instance, if you hear air coming out the valve cover oil filler neck/oil dip stick, then that is rings. If you hear air coming out the exhaust, then that is an exhaust valve issue (bent valve/carbon build up on valve/seat, worn seat/valve, etc...). If it's coming out the air intake, then an intake valve issue. And if your hear air or see air bubbles in the cooling system, then a head gasket issue. You can also check to see if you hear air coming out the adjacent cylinder(s) spark plug holes for head gasket or large cylinder wall crack/hole. I just did a leak down on an engine and saw this very issue. Pressure in cylinder 1 with air coming out the exhaust, plugged the exhaust and then got air out cylinder 2 spark plug hole..... NO BUENO
You neglected to take into account leakage by the valve seats.
Thank you !!
The valves can leak as well.
Ans so can a head gasket.
Yes, part of the system analysis… add oil to the cylinder to rule out the rings… then tap on the valves to confirm they are seating / sealing (oh, don’t forget to evac the oil before replacing the spark plug)
Leak down test is standard for aircraft (Piston) engines.. that’s because you can’t pull over when you break down 😢