So you’re dialing up the details on a fresh small-block Chevrolet build; you’ve got the short-block together and have moved to the top end of the engine. There’s just one small detail you’re not sure about: how to properly adjust each pushrod guideplate to ensure valvetrain stability. That’s where August Cederstrand and the fine folks at Edelbrock [1] come in. They’ve put together a Tech Tips video on how to set up your guideplates to do their job with a minimum of muss and fuss.
The guideplate has one simple job: to keep your pushrods aligned properly so they actuate the rocker arm, and keep the rocker arm stable as it follows its arc. Guideplates are necessary in many high-lift, high-spring-pressure environments, especially when valvetrain geometry has been altered due to cylinder head modifications. Correct valvetrain geometry is the key to long engine life, so the small step of setting up the guideplates is important. One thing to note–guideplates are manufactured from case-hardened steel for durability and require the use of hardened pushrods, or the guideplate will eat through the pushrod material.
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The adjustment process is simple. Once the heads are installed onto the short-block, roll the engine to Top Dead Center on the compression stroke for the particular cylinder you wish to adjust, then loosen the rocker arm studs slightly so the guideplate can be moved, but not so much that the guideplate is flopping around on the stud. Slide the rocker arms onto the studs for that cylinder (you don’t need to bolt them down, just slide them on), then tap the guideplate into the correct position.
Cederstrand says that there should be at least .005-inch clearance between the pushrod and the wall of the pushrod hole in the cylinder head. Once the proper clearance is set, remove the rocker arms from the studs, then tighten the studs down, following with a torque wrench set to the proper measurement for your particular studs. You must ensure the guideplates do not move during this step.
At this point, install the rocker arms onto the studs and verify that the rocker arm tips are centered above the valve stems, and double-check the alignment of the guideplate to cylinder head and pushrod. Check the alignment for each cylinder, ensuring the engine is set to TDC first. It’s a simple process, but a necessary one. Check out the video for more.