It's been a while since I've done this, so I need a refresher course. It'a a ZZ4 roller cam motor. Had a cracked block, I changed the block. Now it's back in the car and ready to fire up for the first time. What's the best way to adj. the valves before firing it up for the first time? Thanks, Dean
The way I have always done it is while assembling is to get the lifter located on the base circle of the cam, tighten the rocker arm down while twisting the pushrod between your thumb and index finger of your other hand to feel when it get to 0 lash then go 1/4 to 1/2 turn past 0 lash the on the rocker arm. Hope that helps. Walter
1/4 to 1/2 turn is good i know there is an easier way of adjusting valves , but i can never keep it straight this is how i do it: bring #1 up to TDC of the compression stroke , you know it's on the top of the compression stroke and not exhaust because the valves on #6 are rocking... set them... then rotate 90 degrees to TDC of #8 ,# 5 will be rocking. keep doing it 90 degrees at a time through the firing order #1 TDC , #6 rocking #8 TDC , #5 rocking #4 TDC , #7 rocking #3 TDC , #2 rocking #6 TDC , #1 rocking #5 TDC , #8 rocking #7 TDC , #4 rocking #2 TDC , #3 rocking you will turn the engine over twice .then bring it back up to TDC of #1 and you are ready to drop in the distributor
That's how I do it too, and it should work fine on this engine. On a really bigass solid cam it's better to get the lifter on the cam base exactly opposite the lobe, so this method is not always surefire....cam companys have the appropriate directions with their cams.
Good advice so far...I add this-I cant stress how important just the 1/2 instead of 3/4 turns, is as the amount to INITIALLY tighten the adjusting nuts on rocker arms.... If overtightened, before running ,even slightly they can damage the lifter [permanently].....preload. the "preload" can be felt by rocking the rocker arm with your fingers-you'll notice the spring tension in the lifter when it touches the pushrod at zero contact... It's a lot safer to do it this way [and maybe have to re tighten em] as to risk the possible alternative.....
For what it's worth, I've seen guys do it this way, get lost somewhere, fire the motor, and bend a bunch of pushrods. Sometimes, it's better to do it the slow way, and adjust each cylinder individually.
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