Riddle me this

["Engfehr, John (J.D.)" <jengfehr@ford.com>]

Why is the compression still so good?
 Remember, compression is taken with the engine spinning at , say 200
rpm - 300. Leakdown the engine is not moving. It is easier for the rings
to seal while in motion and with 200 psi load on them, compared to a
static leak down test.

John Engfehr