sbc / bbc valve train adjustment

[rage'nrat638]

The adjustment is 1/2 turn down from zero lash. (GM MANUAL SAY'S 1 TURN)

In order for the hydraulic lifter to work correctly, it must be centered.
If your valves have come out of adjustment after several thousand miles of
operation, suspect your rocker arm nuts, and replace them. They do wear out
after constant adjustments.


When adjusting your valves, tighten all adjusting nuts until all lash is
removed by feeling the rotation and up and down movement of the pushrod. Next, set your engine on
TDC #1, pointer at "0". You can now adjust the following valves:


INTAKE on cylinders 1,2,5,7
EXHAUST on cylinders 1,3,4,8


Loosen the adjusting nut until lash is felt by rotating the pushrod. Then
tighten the adjusting nut while rotating the pushrod until all lash is
removed. Now tighten the adjusting nut 1/2 full turn. This "centers" your
lifter.


After you have adjusted the above valves, rotate you engine 360 degrees
bringing the pointer around to the 0 TDC mark. This is TDC #6. Adjust the
following valves in the same manner:


INTAKE on cylinders 3,4,6,8
EXHAUST on cylinders 2,5,6,7


Your valves are now adjusted properly.
good luck and may the force be with you
as per the g.m manual..

[woodridge]

I have used this for years and is the best way. Thanks for posting this, I always have to go to the book.

[Billla]

Originally Posted by rage'nrat638

The adjustment is 1 turn down from zero lash.

As noted previously, this is not true for all cams.

[corn]

Originally Posted by Billla

As noted previously, this is not true for all cams.

High RPM engines usually run between 1/8-1/2 turn. I generally run 1/2 turn on everything...

[65-72 chevytoys]

WHen you say zero lash which is the same as remove all lash. THat is when you can feel the push rod rotate underneath the rocker and tighten the nut until the push rod just stops the rotation correct?

[Billla]

Originally Posted by 65-72 chevytoys

WHen you say zero lash which is the same as remove all lash. THat is when you can feel the push rod rotate underneath the rocker and tighten the nut until the push rod just stops the rotation correct?

Zero lash is when there is no vertical movement of the pushrod, typically when you just start to feel drag when rotating the pushrod. Tightening until you can't turn the pushrod is far too tight!

[65-72 chevytoys]

Ok assuming I have the right TDC on the compression stroke. I tightend each rocker nut until I felt drag on the pushrod then tightend another half a turn. I am thinking this is what mark is talking about. However Billa once I tightend the extra half turn I could not turn the pushrod anymore. Should I loosen it up again so the pushrod turns? Then when I rotated the engine 360 to finish the rest of the valves the pushrods on #1 cylinder can turn again. Now I am confused?

[Billla]

Originally Posted by 65-72 chevytoys

Ok assuming I have the right TDC on the compression stroke. I tightend each rocker nut until I felt drag on the pushrod then tightend another half a turn. I am thinking this is what mark is talking about. However Billa once I tightend the extra half turn I could not turn the pushrod anymore. Should I loosen it up again so the pushrod turns? Then when I rotated the engine 360 to finish the rest of the valves the pushrods on #1 cylinder can turn again. Now I am confused?

You're doing everything right You shouldn't be able to turn the pushrod once you've established the preload with the 1/2 turn.

What you're doing here is pushing against the spring inside the hydraulic lifter.

[65-72 chevytoys]

Thanks that cleared up the confusion. Now I have to make sure I had the right TDC. I think I did because both the intake and exhaust valves were closed. If I had been 180 out the exhaust would have been open correct? and should I go past 1/2 turn to 1 full turn?

[Billla]

Originally Posted by 65-72 chevytoys

Thanks that cleared up the confusion. Now I have to make sure I had the right TDC. I think I did because both the intake and exhaust valves were closed. If I had been 180 out the exhaust would have been open correct? and should I go past 1/2 turn to 1 full turn?

Correct; if both valves were closed (on the base circle) then you are on TDC compression...right where you need to be.

[65-72 chevytoys]

Thanks Billa you have been a big help. I have the valves adjusted and right. Now all I need to do is start the engine and see if that fixed my lifter noise.

[Billla]

Originally Posted by 65-72 chevytoys

Thanks Billa you have been a big help. I have the valves adjusted and right. Now all I need to do is start the engine and see if that fixed my lifter noise.

We'll be rooting for you - let us know how it goes!

[prostreet1967]

im guessing since the firing order is the same for a small block and big block u adjust the same valves on number 1 and 6