Table of Contents
- How Do I Identify Rocker Arm Style ?
- Where can I find specifications on valve adjustment lash ?
- Why do I have to Adjust the valves ?
- Who would want to adjust valves ?
- What is a Cam Card or Spec Card ?
- When and why is this adjustment necessary ?
How do I identify Rocker Arm Style and other stuff?
The top one is hydraulic and the other one is mechanical. (stock type)
(Brent-this is just a polaroid picture....will have better later on)
Driver side assembly for hydraulic FE and observed problems.
N/A
Passenger side assembly for hydraulic stock style rocker & shaft.
N/A
Passenger side stock FE head for Hydraulic setup.
N/A
DOVE Roller Rocker Assembly Factory Assembly Instructions which include the torque specs.
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Where can I find specifications on valve adjustment lash ?
Camshafts come with a "Cam Card", be sure to keep it and when you do find your specifications (cold or hot) write them inside & under the Valve Cover with a black magic marker for future reference.
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Why do I have to adjust valves... ?
Because I said so and the engine will operate like it's suppose to. The entire valve timing and performance of the engine revolves around the valves opening & closing at a perfect point in time. To much gap and the engine can be lazy etc. You will also find many problems before the become catastrophic such as a cam lobe going down, a roller lifter starting to go bad and a rocker valve face going bad etc.
The lash should not change very much from setting to setting and consistent lash means something is right and not wrong! When we run aluminum heads we also run a tighter lash to compensate for expansion differences etc. Every after market Cam has a lash specified on the cam card and if you don't have a cam card then we will have to find an optimum lash by some trial and error. That's another story though!
Who would want to adjust valves ?
A responsible Cobra owner who wants to "Walk the Walk and Talk the Talk" and has a vested interest in being sure his engine is in great working order. Don't let "Mechanical" turn you off...it's a great thing to learn what your engine is doing and something you will always know how to do. (keep the little reminder note in your billfold!)
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What is a Cam Card ?
Here's a cam card from Comp Cams....notice valve adjustment is specified at .020" on the intake and exhaust. Notice the recommend valve springs are specified as 929-16. The information you need to degree an installed camshaft is available too.
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When is the adjustment necessary ?
Valve lash on mechanical camshaft rocker arms needs to be checked at least twice year and more often when you plan to race or need the engine running at optimum power. For the average Cobra guy it should happen more often because they don't know how to drive slow and are always stretching the limits of these engines! Lash is important if you want the most power and the longest life possible.
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Author George Anderson.
Copyright © [Gessford Machine Inc.]. All rights reserved.
Revised: November 11, 2000.
