Johnson Lifters Guide: Lifter Adjustment
  • Consult cam card for specs
  • Rotate engine to cyl. 1 exhaust valve opening
  • Adjust intake
  • Rotate engine to cyl. 1 intake valve closing
  • Adjust exhaust
  • Repeat per cylinder

Adjusting Solid Lifters

The Cam Card that comes with your camshaft will list the specified “hot lash” or running clearance for your solid lifter (mechanical) camshaft. To set your valves follow the universal “Exhaust Opening/Intake Closing” procedure. This method ensures that the lifter is on the base circle of the cam when you make the adjustment. The adjustment procedure is the same for both flat tappet and roller solid lifters.

Working on one cylinder at a time, rotate the engine in the normal rotation until you observe the exhaust pushrod start to rise or the exhaust rocker start to depress the valve. At this point make the correct adjustment to the intake valve. Tighten the rocker nut with the correct thickness feeler gauge inserted between the rocker arm and the valve tip until you feel a slight drag when moving the feeler gauge.

Then continue rotating the engine in the direction of normal rotation until the intake valve is fully open (valve spring fully depressed) and is just beginning to close (rocker arm and spring rising).

Now set the exhaust valve using the same procedure. If the exhaust valve calls for a different valve lash (often slightly looser) be sure to switch your feeler gauge to the correct adjustment.

Repeat this adjustment on the rest of the cylinders. Racers often find it convenient to work down one side of the engine and then switch to the other side of the engine when making lash adjustments.

When you start the engine the lash will change according to temperature and the type of cylinder head. Run your break-in procedure and then re-lash the valves while the engine is still hot.

Adjusting Hydraulic Lifters

Hydraulic lifters require proper preload adjustment for optimum performance. Preload is required to eliminate valve train noise and wear and to provide the proper hydraulic function. However, excessive preload can cause low vacuum, rough idle and valve train damage. Hydraulic lifters are adjusted the same way as mechanical lifters, but there is an additional step.

Working on one cylinder at a time, rotate the engine normally until the exhaust pushrod just starts to rise or the rocker arm just begins to open the exhaust valve. Now tighten the adjusting nut on the intake rocker until all the clearance is eliminated. You can tell this by rotating the pushrod between your fingers while tightening the nut. When you feel a slight drag, you have eliminated the clearance. Then tighten the nut the additional clearance specified by the cam manufacturer. This is typically one quarter to three quarters turn down.

Once you have set the preload on the intake valve, follow the same procedure for the exhaust valve by rotating the engine until the fully open intake valve just starts to close. Then make your preload adjust on the exhaust valve. Some racers like to adjust their hydraulic lifters to zero lash to guard against pump up. We recommend at least some minimum amount of preload to keep the plunger from riding on the retainer clip and risking potential failure.

Setting Preload for a Non-Adjustable Valve Train

The recommended method is to determine the pushrod length at zero length using an adjustable checking pushrod. Once you have determined the zero lash pushrod length, order a set of pushrods with the additional length to provide the specified preload.

For example if you determine that the zero lash point is achieved with 7.25 inches with the adjustable pushrod simply add your preload requirement to that length, i.e. 7.25 + .050-inch or whatever preload your cam manufacturer specifies.

For GM LS engine with non-adjustable rockers, the recommended practice is to find zero lash with an adjustable pushrod. Then order longer pushrods with the desired preload built in. Iron block engines do not expand as much so you can specify a preload of 0.015-inch.

For aluminum blocks order pushrods that are 0.025-inch longer as the parts will grow into the desired preload as the engine warms up.

This same method can be used on all non-adjustable rocker engines to obtain the desired preload by ordering the proper pushrod length, thus guaranteeing the optimum valve adjustment for your particular engine.

How to Identify Which Valve You're Adjusting

The most common procedure for adjusting lifters one cylinder at a time is the Exhaust Opening/Intake Closing method. This method sets the intake valve when the exhaust valve is just starting to open and the exhaust valve when the intake valve is open and just starting to close. This guarantees that the lifter is on the base circle of the camshaft for each adjustment. Adjustments are made one cylinder at a time by rotating the engine or bumping the engine over with the starter until you observe the proper valve action at the rocker arm tip. 
The exhaust valve will always be located above an exhaust port as seen here.
Your feeler gauge should feel a slight drag as you push it between the rocker and the valve tip.
When the exhaust rocker just starts to depress the exhaust valve, set the intake valve adjustment.
Wth the rocker adjustment nut backed off you can turn the adjuster until you feel a slight resistance at zero lash.
When the adjacent intake valve is fully open and the rocker starts to rise, set the exhaust valve adjustment.
At 50% of net valve lift your rocker arm tip should sweep to the center of the valve tip as shown here.
Johnson Lifters® products are covered by a general warranty that states that its products will be free from manufacturing defects in materials and workmanship. The length of this warranty for automotive parts is as follows: Johnson Lifters are guaranteed for the life of the engine and will be replaced if any failure is deemed due to manufacturing defect and sold under the Johnson Lifters® name.

All Johnson Lifters warranties assume that the product(s) were properly installed, subjected to normal use and service and that they have not been modified, neglected or used on racing or competition applications. The warranty covers only the product itself and not the cost of installation and/or removal or any claim of collateral damage.

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