I have a Firebird with the Pontiac 400 engine. I am just putting the
engine back together after a crank regrind. Haynes tells me just to
tighten the rocker arm pivots nuts to 20 lb-ft which is what I did last
time I had this engine apart and I am wondering if this is what caused
the 2 bent push rods. I have read elsewhere that I should tighten the
rocker arm nuts so that there is no play in the push rods and then
tighten them another half turn. I have tried this but they are nowhere
near 20 lb-ft. (except for the 2 where the nut has "bottomed out" at
about a quarter of a turn). I am worried that they are going to rattle
loose. What is the correct way to set them.
Thanks for any information.
The 20 ft lbs is correct. The 400 has a non-adjustable valve train. The
other procedure is for adjustable valve train engines like the Chevy. If
you bent push rods something else was wrong. Did you over rev it?
If ANY of the original factory valve train has been replaced you need to
switch to an adjustable valve studs.
You need to intall Big block Chebbie rocker studs with crimp nuts. Then
you turn the engine in 90 degree increments and adjust the respective
I worked on a friend's 350 Pontiac and tried to adjust the valves like
it was a Chevy small block. The rocker nuts all backed off and he made
it back to my place on three cylinders.
The Summit tech line told me there were special locking nuts available
or I could probably just torque them all down. So I tightened them all
the way and it worked fine.
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