Setting and adjusting the valve lash is often overlooked as a simplistic and unsophisticated task for proper engine maintenance, yet much can be gained by paying attention to valve lash. Good initial set up and keeping a close eye on the valve lash can alert you to a problem before it leads to a pernicious death of your powerplant.
Valve lash, which is the clearance between the tip of the rocker arm and valve stem tip, is a delicate balancing act between durability and maximum power. Most camshafts will come with a cam spec card that has a recommended valve lash setting.
Excessive valve lash will cause wear in the entire valve train while setting the lash too tightly will cause the valves to hang open and lose an excessive amount of power if it runs at all.
Regardless of what you’ve heard, there’s no mystery to setting valve lash on flat-tappet cams. Whether you’re dealing with hydraulic or mechanical flat tappet cams, we’ve got the procedure that will make this very important task as smooth as butter.
Install the adjusting nut by tighten the nut “finger tight” to the point where the pushrod has no lash, but will still spin with your fingers. Repeat this process until all pushrods are seated and all rocker arms are installed.
Finally, it’s time to set the valve lash. Our experts have told us that the best way they have found is to set the lash, one cylinder at a time, in the correct firing order. Make sure that the dampener bolt is installed in the crankshaft, turn the engine over by hand in the direction of its normal rotation.
Following the method outlined in the video will help your pushrod engine run consistently and longer between overhauls.