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Connecting Rod Installation

The following is a method of verifying proper valve train geometry. After you have estimated the required pushrod length using a Lunati Pushrod Length Checker, use this method to verify that the valve train geometry is correct (using the rockers you are using in your engine.)


STEP 1

Step 1

The first step is to install a solid lifter and an adjustable pushrod. Mark the tip of the valve with a marker.


STEP 2

Step 2

Install your rocker arm and set it up with zero lash. Rotate the crankshaft clockwise several times. Remove the rocker arm. The contact pattern of the rocker tip will be where the marker has been wiped away from the valve tip. The pattern should be centered on the valve tip, and as narrow as possible. If it is not, experiment with varying the pushrod length to yield the best pattern.


STEP 3

Step 3

Rotate the crankshaft clockwise several times. Remove the rocker arm. The contact pattern of the rocker tip will be where the marker has been wiped away from the valve tip. The pattern should be centered on the valve tip, and as narrow as possible. If it is not, experiment with varying the pushrod length to yield the best pattern.


STEP 4

Step 4a

Pushrod Too Long: Notice how the pattern is wide, and shifted to the exhaust side of the valve tip


Step 4b

Pushrod Too Short: Notice how the pattern is wide, and shifted to the intake side of the valve tip.


Step 4c

Pushrod Length Correct: Notice how the pattern is narrow and is centered on the valve tip.