Pontiac GTA Enhancement information and discussions with Technical DIY and performance tuning information for the hardcore Pontiac GTA Owners and Enthusiasts.
Forum | Register Now | Members | Search | How Do I... | Calendar

Go Back   The GTA Source Page Message Forums > GTA SPECIFIC > GTA TECH

GTA TECH Want to discuss technical topics about your GTA.... engine tuning, mechanical upgrades, problem areas, etc.? Then post it HERE!

Thread Tools Display Modes
Old 12-11-2000   #1
Posts: n/a

Adjusting Valve Lash

I just got done installing a TPIS ZZ-9 Camshaft in my L98 TPI (1988 GTA 5.7L). I have Comp Cams 1.52 Ratio Self-aligning Roller Rockers. With the increased lift on the camshaft, the rocker arm travels so much more that I can't get a socket on the adjusting nut on the rocker arm. I tried to adjust the valve lash while the engine is running but it is impossible. The socket keeps being thrown from the rocker arm. I called TPIS for some advice but they told me to:
Adjusting lifters is the last of the assembly steps. It is also a good place to get messed up. The following procedure works for all 4-stroke engines:

1. Insert all pushrods.

2. Pick any cylinder to start with.

3. Turn motor over until you just see the exhaust pushrod move.

4. Install the intake rocker arm.

5. Install the rocker arm adjusting nut.

6. Tighten nut until all free play is gone. (Be careful not to collapse lifter)

7. Turn motor over until intake pushrod opens all the way and then just close. Now repeat steps 4 through 6 for the exhaust rockers.

8. Do all the other cylinders.

9. Now tighten all adjusting nuts one more turn.

Should I follow this advice? Will i have to do a readjustment after the engine is running or can I stick to this? Thanks.

  Reply With Quote
Old 12-12-2000   #2
Multi-Vehicle Member
Join Date: Oct 2001
Location: Near Tulsa, OK
Posts: 267


This procedure works. Once you've run the valves their done forever on a hydraulic lift cam. When you tighten the rocker nut until the "free play" is gone means, when you can no longer spin the pushrod with your thumb and index finger with little effort. After this I will always turn the nut between 1/2 of a turn and 3/4 of a turn more. This is not the best description of the valve setting process I have ever heard. It leaves room for too much error. Check your local part store for an engine rebuild book with a more descriptive process. I like to use ones that reference checking specific cylinders for top dead center as a back-up for what cylinder you should be cranking down.
Has-been GTA Owner.Brent
Brent87LT1 is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -5. The time now is 07:26 AM.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.