[glhs#116]

Originally Posted by HWYSTR455

Wow, bummer. Couple things that I'm not clear on, so going to ask. You say you started with 1 full turn of preload, and then after that you added another 1 3/4 turn? So the total was 2 3/4 turns? That's way too much if that's the case. As a reference, posted this a few times, the amount of preload for each turn depending on the stud threads:

http://www.johncalliesinc.com/pdf/Ad...licLifters.pdf


b. 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".
c. Next, divide .050" divide by 4 to calculate the distance for a quarter-turn of the adjuster nut (.050" / 4 = .0125").
d. For a 3/8 x 24 adjuster nut, the calculations are:
1" / 24 TPI = .042" per full turn and .042" / 4 = .0105" per quarter-turn.
e. Use the chart below to determine how many quarter-turns to tighten the adjuster nut after Zero-lash:
Cast Iron block and Cast Iron Head = .020" - .025"
Cast Iron block and Aluminum Head = .030" - .035"
Aluminum block and Aluminum Head = .045" - .050"

HFT lifters generally require @ .030-.060 preload. So, max I would think would not exceed 1 1/4 turns, roughly.

You commented:

"I adjusted the rockers with one turn preload one at a time in firing order turning the engine over by hand 90 degrees each time."

Can you explain that better please? Your process?

EDIT: Keep in mind the extract above is when using Morel HYD Roller Lifters, which call for @ a preload of .020-.025, and for an iron block, with aluminum heads, add .010-.015. So for a HFT lifter, roughly .075 is max.

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I will certainly revisit the preload but none of them were bottomed out and the car runs and drives normally.

As far as the sequence, it's one Cliff posted somewhere. If you are at compression TDC for #1 then both its rockers are at base circle on the cam. You can adjust those. Then rotate engine 90 degrees and do the same for the next cylinder in the firing sequence. In two full rotations you have done all the valves on the base circles..

Sam