Adjustment of mechanical/solid-lifter valve lash on
216/235/261 Chevrolet truck engines
(for stock cams)
1. Make sure that each rocker arm surface that mates with the top of the valve stem is smooth. Grind smooth and polish, if necessary.
2. Warm up engine to a stable temperature and then run the engine for 30 minutes (this is important) .
3. Stop the engine.
- the exhaust valves are on the ends of the head (look at the intake and exhaust manifold)
- use a flat feeler-gauge
- the settings below are in inches
- the settings below might be different for different years' engines
- the settings and instructions are for standard 216/235/261 cams and rocker-arm assemblie
- if the engine has been rebuilt and/or the rocker-arm assembly has been removed/replaced, the clearance settings will have to be set "cold" and 0.005" should be added to the clearance settings given below
Valve Lash - Clearance settings
- see links to GM document at the bottom of this page
- different Chevrolet documents often give different settings even in the same year
216 cubic inch engines
Intake: .006" to 008"; .010" for heavy duty operation
Exhaust: .013" to .015"; .020" for heavy duty operation
235 cubic inch engines
Exhaust: .016" or .018"
261 cubic inch engines
Exhaust: .018" (up to 1 ton trucks); .020" for 1 ton and larger trucks
4. Set the motor to fire on #1 cylinder. If the following valves are not fully closed, rotate the engine one full revolution (the crankshaft moves two revolutions to fire all 6 cylinders; the camshaft moves one full revolution for every two revolutions of the crankshaft).
Set the lash on:
Then, rotate the crankshaft one full revolution.
#6 cylinder should be in firing position (the following valves should be fully closed).
Set lash on:
The following information are links to material kindly provided on the Internet by Keith Hardy (thank you, Keith)
Note that the following clearance settings "specifications" are often given as different values in different GM manuals during the same year.
The following procedure is similar for almost all years of 41-63 Stovebolt Six engines
Tim Lederman (firstname.lastname@example.org)
26 May 2001 (last revised on 14 July 2009 - links to Shop Manuals were added)