| z28pete |
Aug 9, 2007 10:45 AM |
Push Rod Checking
Pushrods, from Comp Cams
http://www.cmotorsports.com/images/pushrods.jpgThe pushrod is the weakest part of the valve train, and in high RPM applications, the stock pushrods can bend under the high load. When doing a cam swap or installing high ratio rocker arms, be sure to check your stock pushrods to make sure they are straight. Simply roll them on a flat surface, and if they don't roll well, they are bent and need to be replaced. The stock pushrods are strong, but higher output engines should upgrade to a one piece chromemoly setup.
A major problem in high RPM engines is incorrect valve train geometry. Make sure that you have the correct length pushrods installed. The easiest way to check is to take a magic marker and color the tip of one intake and one exhaust valve. Then, install your pushrods and crank the engine over a few times. Now uninstall the rocker arms and look at the tip of the valves that you colored. The marker will be worn away where the rocker arm was in contact with the valve. This line left should be in the center of the valve. If it is towards the exhaust side of the head, you need shorter pushrods, if it is towards the intake side of the head you need longer pushrods.
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