Leakdown Testers

[Mike Pearson]

Originally Posted by reknapp52

Turns out my brother has a Matco tester that I will be using. Do I need to warm the motor before running the test? It's been parked in my garage for about 3 weeks without being started. Also, what numbers are acceptable? My motor is 447 C.I. with 14.3 compression.

Depends a lot on the ring type and end gap. Also piston to wall clearance will effect the readings. 10 or better is what you are looking for. You don’t want any blow by on the intake valve. That is a killer. Also equal across all cylinders is another good sign. Leak down is a tool not a tell all.