View Single Post
TurboKraft TurboKraft is offline
Registered User
TurboKraft's Avatar
Join Date: Mar 2005
Location: Phoenix, AZ
Posts: 2,534
Was this performed on a warm engine or cold?
We use 6% as our upper limit on a cold engine.
Normal after a rebuild is 2-3% on new P&Cs, and maybe 4-5% if re-ringing the existing P&Cs.
8% seems a little high, but there's information missing: is it leaking past the valves, or the rings? Did the tech try tapping on the ends of the valves (rockers) to see if it's past the valves, and did the numbers change?
We just in the shop had a 930 that had barely been driven over the past 18 months, and very gently -- lots of carbon. Leakdown on an exhaust valve was 12%, and after a few taps the carbon cleared off the valve/seat and it was 4%.
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: -
Old 10-03-2011, 09:15 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)