[30 Closed Cab PU]

More info. What I had happen to me.


I had my motor rebuilt last winter. The motor did not have adjustable tappets, so adjustable tappets were installed. When I got it back after about 200 miles the motor started a tapping noise. I went back to the place that pulled and re-installed the motor for me, and they adjusted a tappet via the valve access cover. Within another 200 miles it started tapping again. They told me to keep driving it, it would not hurt anything. The tapping did not get worse.


So I drove it for awhile, and contacted them again, they towed the truck to the motor builder and the motor builder replaced a couple if tappets. Issue appears fixed, 1500 miles no tappet noise.


So even with new parts and using the non-locking nut design, my motor still had this problem.


Since it looks like you have your motor apart/out of the car, valve access cover off, checking the gaps should be fairly simple. If you had an issue you would have heard a tappet(s) loudly tapping if the gap widened, or the motor would not run evenly if the gap had closed causing the valve not to open or fully open. There maybe other symptoms I am unaware of, am not an expert.


If you end up replacing the lifter with the other design, there is a preferred manufacturer.


Here is the info - "at one time there were 3 suppliers, two Chinese and they are problematic. Typically too small on the diameter which causes wear on the cams, and also issues with holding adjustment due to quality issues in production causing them not to hold properly.. They mention using USA Colony Adjustable Tappets, available through Snyders and Berts, best to ask before ordering."


Also preferred adjustment is .013 Intake, .015 exhaust.


Hope this helps.