Lifter Pre-load

Just wondering what you guys think is the optimal lifter pre-load for stock lifters (pro-mag rockers). Right now I have my lifters adjusted at 1/6 of a turn pre-load, and im paranoid that might not be enough. Been driving it that way for about 1000 miles and it definitely has the "sewing machine" sound from inside the car... but ive heard this is perfectly normal.

I might be going to the track this saturday (and hopefully get my tune somewhat dialed in). I dont want to collapse a lifter if i can help it haha.

opinions?

I always ran 1/4 turn, it ran better at 1/4 than it did at 1/2 on mine. most people say 1/2 but it was to much on mine. 1/6 isnt enough tho.

Don't overtighten; zero lash + 1/4 is as far as you want to go.
Lifters "pump up" as RPM increase, which will cause the lifter preload to battle against
the spring pressure, which leave valves open at high RPM.
That can mean loss of power at the top end or worse .... BANG BANG BANG.

The "sewing machine" sound is normal.

1/4 on mine, sewing machine too. Stock lifters/GMPP 1.6 RRs/Hotcam/LT4 springs with all the LT4 goodies (obviously).

Runs balls to the wall up top though, no problems here.

i think i set mine to 1/4 it was either that or
3/8 (1/4 + half of 1/4)

i have chromemoly pushrods, crane 10308 springs, ls7 lifters, and promags
I have never heard my valvetrain quieter than it is after this adjustment

Yeah 1/2 is a little too much I think, somewhere in the area of 1/4 is fine....

Stock lifters I'd go 1/2 turn past zero. IIRC factory called for 1/2-3/4 turn.

should i bother re-adjusting from 1/6 to 1/4?

I was thinking about trying the engine running method to save me a lot of time.

Quote:

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Originally Posted by Fastbird

Stock lifters I'd go 1/2 turn past zero. IIRC factory called for 1/2-3/4 turn.

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I've always set mine at 3/4 turn.

My engine builder absolutely swears by just barely taking out the "noise". He basically goes to zero lash and then, maybe like 1/20th of a turn, no more than that. You CAN run into problem at really high-rpm if you have them too tight.