SPANKY LS1

iTrader: (24)

About two weeks ago, I installed my new H/C package. All of the following parts were new: APE S1 heads, FMS cam, 7.400" chromoly pushrods, new OEM lifters, and HS 1.7 rocker arms. Because the lifters were new, I could not check preload because the lifter wasn't "pumped up", and was "collapsing" as the rocker arm was torqued down, so I just torqued the rockers down to ~22 lb/ft. I'm wondering if my preload could be off (it may or may not be, but its something to check, IMO). How do I check/set preload on a non-solid lifter setup? How do I adjust it if need be, shims? How much preload do I need? Hiw much could it be costing me on the dyno?

Thanks, Shawn

destroyerSS

iTrader: (2)

with the OEM lifters i would assume that since you have ran the car i would go back and loosen the lifters and retorque now that your lifters are full, not sure though. I do know that saturday morning i'll be setting the preload on my car.{Comp R's and harland's}

Dustin Butts

iTrader: (5)

It doesn't matter if they're pumped up or not. The easiest way for me is like this:

Pull the drivers side valve cover.

Get the cylinder to TDC.(Turn the crankbolt til the intake valve is closed and the exhaust valve is just starting to open.)

Take off the #1 intake rocker arm.

Pull out the pushrod.(Before you pull the PR out make a mental note of the area of the PR that is near the PR hole in the cylinder head.)

Take masking tape and wrap it around the PR in the area of the PR hole in the head.

Put the PR back in the hole and put the rocker arm gently on the PR.

Tighten the rocker bolt til you barely feel the PR touching on the lifter.

Now take an x-acto knife, pencil or sharp felt tip pen and mark a line on the tape on the PR near the hole in the head.

Now tighten the rocker all the way down and torque it properly.

Wait about 1 minute and make another mark on the tape on the PR.

Now remove the rocker again and pull out the PR.

Measure the distance between the two marks on the tape.

That is your preload. IMO it should be around .03-.06(1/32-1/16")

This is not a super scientific or super accurate method, but it works. Usually a couple .01's or so either way won't hurt. A 7.35 or a 7.40 pushrod is all 99% of people will ever need or use.

PREDATOR-Z

Harland Sharps are non adjustable

Now that your car ran for awhile, you can retighten them.

Way to do that is super easy.

1- Take off valve covers
2- loosen rocker bolts 1/2 a turn and retighten to 22 lbs/ft
3- put the valve covers back on

That is all.

Now I see you have after market heads. A couple of Qs:

1- Were they milled?
2- How much?

Dustin Butts

iTrader: (5)

Comp is now making pushrods for our cars in .025 increments. So you could get a 7.325, 7.350, 7.375..etc if need be. Ain't that neat...?