Adjusting valves - zero lash?
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
Re: Adjusting valves - 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.
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 !?
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Adjusting valves - zero lash? (Sliding)
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.
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.
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
is that just for the 219 cam or any cam?
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
Re: (scorp508)
In the shop manual there's a technique that I use that only requires the engine be turned over (360 degrees) one time. You start with the timing mark set on zero with the #1 cylinder at TDC. (pull the first spark plug on driver's side to know when it's at TDC) In that position you adjust the following valves: Exhaust 1,3,4,8 Intake 1,2,5,7. Rotate the engine 360 degrees to zero. (This puts # 6 at TDC) adjust the following valves: Exhaust 2,5,6,7 Intake3,4,6,8. Done!
Did anyone else use this technique, and is it good?
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Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Re: (Sliding)
Did anyone else use this technique, and is it good?
Race Director
Joined: Dec 2002
Posts: 13,348
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Re: (C4Crazy787)
Wouldn't it be nice to have a valve cover with an opening for adjusting valves with the engine running? :iagree:
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]
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
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)
Melting Slicks
Joined: Apr 2002
Posts: 2,118
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From: St. Charles, MO Route 66 Corvette Club
Re: (scorp508)
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!
Racer
Joined: Jun 2002
Posts: 428
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From: Dallas Tx
Re: (scorp508)
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.
Don't know what the business of increasing the turns to increase cam duration and/or early lift is all about.
