[HWYSTR455]

Originally Posted by "QUICK-SILVER"

Need to measure preload NOT "or" 1/2 to 3/4 turn.

Rocker stud size and rocker ratio will change preload a bunch.

1/2 to 3/4 is factory BBC directions for 7/16ths studs and 1.7 ratio rockers.

Need the OP's lifter specs for preload. Then measure one to see what turn is needed to get it right. Rest can be done by turn amount after that.

Clay

Let me start here. Ok, as John Callies has outlined in the past:

"If your adjuster nut is 7/16 x 20 threads per inch, then divide 1 inch by 20 threads per inch. One complete turn down on a 7/16 by 20 adjuster nut will move .050"."

So, in general, HFT lifters require between .030-.060 preload. 1/2 a turn would be .025, and 3/4 would be .0375, well within the required range, without going to far. You could go all the way to 1 full turn for .050, and again, would be within the required range.

Doesn't matter what kind of rocker you have, from the stud to the pushrod on the rocker isn't where the ratio is changed for 1.5 to 1.65 or 1.7, it's towards the spring side the ratio changes.

69 Limelight - Yes, that is what you posted, but my comment was to TAQuest:

"Rotate the engine again until the intake valve has fully opened. Now you can adjust the exhaust valve to zero lash, then 1/2 more turn."

Which was posted in response to your comment. The difference, which we both caught, was that the adjustment was made at the point the intake was fully open, not 'almost all the way closed'. And that was what I was trying to point out. (as others were as well)

TAQuest, I suggest you go back over the exhaust adjustments.

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