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Does anyone have any experience setting the lifter preload and torque spec for poly lock rocker nuts? Recently had one of the bodies crack on one of the rocker nuts and want to replace all the nuts for good measure but I don't have experience with the poly locks. Any info would be great.
I understand poly locks didn't come from factory in the LS, the valvetrain on mine is aftermarket for the Texas speed cam that's in it. So thus the reason why my car has poly lock rocker nuts. I'm just simply asking how to properly torque them and set the lifter preload.
I've never seen such a setup on an LS.
Typical installation would just have a bolt there, and preload is adjusted by selecting the correct pushrod length.
Whose setup is that?
At any rate, you would typically set it X number of turns from 0 lash, cam on the base circle, to establish preload. Then crank the set screw down, and give the poly lock a bit of an additional turn to lock the two together. Had more than a few Rat motors with that setup and that was how it's done.
I understand poly locks didn't come from factory in the LS, the valvetrain on mine is aftermarket for the Texas speed cam that's in it. So thus the reason why my car has poly lock rocker nuts. I'm just simply asking how to properly torque them and set the lifter preload.
Many years ago, when the LS1 was in its infancy, I remember seeing a magazine article about going back to rocker studs, and setting preload (and rocker arm geometry!) like the Gen1 SBC. Other than that, I've never seen that done on an LS motor. Are your rockers stud mounted?
Started about 20yrs ago that every enegin my neighbor and i build we put adjustable poly nuts. For the simply reason don't have to mess with pushrod length when changing cams. My arm is my torque wrench so cant help u there. More money ,but no headaches. There is a slight learning curve on tightening which u r running into.
Don't overthink it. Tightening has nothing to do with adjustment. So don't be scared to give it a little bite. But not crazy.
I'll also add that the top end of the stud, the "face" that the set screw tightens against, needs to be pretty flat. Last time I ran Polylocks, I surface ground the studs at the upper end.
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Rocker Nuts coming loose
