View Full Version : Lifter Pre-load
JoeliusZ28
10-21-2008, 07:33 PM
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?
lethal93ta
10-21-2008, 08:17 PM
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.
James Montigny
10-21-2008, 08:37 PM
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.
Fixxer99TA
10-21-2008, 09:06 PM
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.
Z28pr0jekt
10-21-2008, 09:18 PM
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
Fixxer99TA
10-21-2008, 09:22 PM
Yeah 1/2 is a little too much I think, somewhere in the area of 1/4 is fine....
Fastbird
10-21-2008, 09:53 PM
Stock lifters I'd go 1/2 turn past zero. IIRC factory called for 1/2-3/4 turn.
JoeliusZ28
10-21-2008, 11:15 PM
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.
lt1-xjs
10-22-2008, 05:35 PM
Stock lifters I'd go 1/2 turn past zero. IIRC factory called for 1/2-3/4 turn.
I've always set mine at 3/4 turn.
joelster
10-22-2008, 07:25 PM
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.
Fixxer99TA
10-22-2008, 07:33 PM
Right, just take the noise out of them. Every car is going to be slightly different too. Wear/age ect... Your safe if the engine sounds like a sewing machine, but anything more and your out of adjustment.
Z28pr0jekt
10-22-2008, 08:36 PM
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.
and you can run into problems at high rpms with them that loose
kinglt1
10-22-2008, 08:43 PM
I thought shbox says to adjust stock lifters to 1/2 turn or so? Comp r's should be around 1/6 or 1/4. somethin about the stock lifter plunger has more travel than aftermarket lifters, so they need more preload.
bolton94Z
10-22-2008, 08:56 PM
I thought shbox says to adjust stock lifters to 1/2 turn or so? Comp r's should be around 1/6 or 1/4. somethin about the stock lifter plunger has more travel than aftermarket lifters, so they need more preload.
This is what I went by too I started with 1/4 turn and then decided 1/2 was the best for me my rockers are 1.6 crower self aligning rocker.
NicksTAgt
10-22-2008, 09:29 PM
*Edited* Make a for sale thread. No hijacking for sales purposes especially.
Admin
Tyler Wheat
10-22-2008, 11:04 PM
I went 1/4 to 1/2 on my pro-mags. I always thought the factory was 1 on a standard rocker. Not sure, though.
James Montigny
10-22-2008, 11:08 PM
*Edited* Make a for sale thread. No hijacking for sales purposes especially.
Admin
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NicksTAgt
10-23-2008, 09:18 AM
indeed :doh:
Tony Shepherd
10-23-2008, 09:29 AM
I have always set the stock lifters at 1/4 past 0 lash and the comps 1/8 past 0 lash.
JoeliusZ28
10-23-2008, 12:21 PM
I have always set the stock lifters at 1/4 past 0 lash and the comps 1/8 past 0 lash.
Im pretty much gonna believe anything this man says haha.
Just to make sure of my methodology... since you cant do the "spin test" with the engine running, do you just listen for the slack to go away and then add whatever ammount of turn past that?
Tony Shepherd
10-23-2008, 03:56 PM
Just to make sure of my methodology... since you cant do the "spin test" with the engine running, do you just listen for the slack to go away and then add whatever ammount of turn past that?
You are correct.
JoeliusZ28
10-23-2008, 04:35 PM
thanks tony
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