Sliding

What exactly do You mean by "zero lash"?

scorp508

With the lifter on the base circle of the cam there is 0 space between the tip of the pushrod and the rocker arm.

Sliding

Thanks, thats what I thought.
Scorp, You also have 219 cam, right?
Did You also adjust valves at zero lash + 1/2 turn ?

I have a problem with very noisy valves/lifters. I have reused old lifters
but they were never noisy before cam and heads job.

I still didn't get the timing right so that may be the problem !?

scorp508

Yep got the 219 cam. I go to 0 lash + 1/4 turn. :)

C10 JDR

is that just for the 219 cam or any cam?

65Z01

The object is to position the piston midway between it's upper and lower limits in the lifter.

I tighten to 1/2 turn + about 1/8 turn. I've found that I can determine zero lash to within 1/8 turn so this puts my preload to 1/2-3/4 turn, which is within limits for my L98.

scorp508

Any really. Some people go more on the turn which opens the valves a little faster and a little more, but puts a small amount more strain on the valvetrain and more parasitic loss. I go with less turn for less loss and supposedly faster rev'ing.

Sliding

I found this technique on forum and I used it with 1/2 turn.

Did anyone else use this technique, and is it good?

scorp508

Yup, thats perfectly fine. Thats how I set mine up before firing it. I do though go back and reset them with the engine running. I always tend to get 1 or 2 a little loose so they clack some. I'll pull a valve cover off while its running and tighten them ALL a little too tight so that they're qutie and then just start with the front and work my way back loosening them slooowly until it clacks and then tightening it sloooowly until it is silent (the point of silence = 0 lash) and then I turn it another 1/4 slowly.

Strick

Wouldn't it be nice to have a valve cover with an opening for adjusting valves with the engine running?

C4Crazy787

:iagree:

rocco16

It's very nice. Years ago I bought a single valve cover and cut a long slot in the top for access to the rockers while the engine is running. Cheap tool.

By the way, Scorp, tightening down a hydraulic lifter will not increase lift, valve acceleration, or duration. (unless you bottom the lifter out, plus a little more)
Someone gave you some erroneous info.

Larry
code5coupe
:seeya


[Modified by rocco16, 1:12 AM 8/4/2003]

scorp508

Eh? I'll let a few more chime in before I comment. :)

Sam Lam

I have a stock cam and lifters in my 89. The Zero + 1/2 gives me very noisy lifters...I have tried it! My "least valve noise" results come from zero + 1 full turn as recommended in the Helms manual. I cannot feel the difference in performance between 1/2 turn vs 1 turn in a stock engine! My $.02 worth!

tkrussell

I have always heard that to maximize hydraulic lifter rev potential, the method was to zero lash plus the bare minimum (1/8 to 1/4 turn). The Chevy Power books among others recommended this technique. Makes sense, in that there would be very little to pump up.

Don't know what the business of increasing the turns to increase cam duration and/or early lift is all about.