Valve adjustment damage?
Thread Starter
Melting Slicks
Joined: Mar 2005
Posts: 2,187
Likes: 7
From: Chetwynd B.C.
Valve adjustment damage?
Recently set the valves on a 454 at 3/4 of a turn after slack on the push rod. Drove it for 15 miles and learned the mechanic said he was going by "memory" that is should be 3/4 of a turn. In the book and also here on the site (after a search) I have read that it should be 1/4 turn. Could there have been any damage caused by this 3/4 turn in the short mileage? I have a HUGE loss of power and even after reseting to 1/4 turn I still have no power. 
shmoky
shmoky
Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
Recently set the valves on a 454 at 3/4 of a turn after slack on the push rod. Drove it for 15 miles and learned the mechanic said he was going by "memory" that is should be 3/4 of a turn. In the book and also here on the site (after a search) I have read that it should be 1/4 turn. Could there have been any damage caused by this 3/4 turn in the short mileage? I have a HUGE loss of power and even after reseting to 1/4 turn I still have no power.
shmoky
shmoky
Mine are set at 3/4 past 0 lash.
What procedure did you use to adjust them?
Here is the procedure from Crane
http://www.cranecams.com/?show=techarticle&id=2
Melting Slicks
Joined: Sep 2003
Posts: 3,050
Likes: 2
From: Orange Ct
One turn is the usual stock setup on most Chevy engines. This will give the most miles without an adjustment. It also works as a rev limiter. When the lifters pump up at high RPM they will hold the valves open and prevent costly damage (saves on warranty costs). Adjusting to 1/4 turn will allow higher RPM but still allow for wear and keep the valves quiet. Most use about 1/2 turn.
