Joel wrote:Have you considered inserting the 0.016 feeler gauge whith the engine running, it will change the sound of the valve in question, if that is the problem.
That is an excellent way to screw up a good feeler set, particularly if the tappet face is recessed due to wear, as it appears is the case under discussion.
Pete Silfven rightly suggested eons ago that if you know the thread pitch you can work out how to adjust the tappet [in the normal adjustment position] without feelers.
Screw up to reduce clearance & get no play, then back off 2 [for 0.014"] & a smidgen more, castellations [flats on nut] for 0.016".
This method will allow for in service wear & get a more accurate adjustment.
You could also use a dial gauge to achieve the same outcome.
If one knows the threads per inch which in this case the tappet is 24 [3/8" X 24] when you turn the adjusting screw one complete turn or rotation, the tappet has moved 0.042" [1.00"/24]
If you move the 6 sided or 6 flats adjusting screw 1/6 of a turn in or out the tappet gap will increase or decrease by 0.007"....2/6 of a turn 0.014"....2.3/6 of a turn = 0.016" so TO ADJUST VALVES WITHOUT FEELERS
Turn the engine until number 1 is @ TDC & number 4 valves are rocking [this means number 1 is TDC compression]
Turn both number 1's tappet adjustment screws to reduce [or increase] clearance, until you just can't rotate the tappet.
Now holding the in block tappet with your tappet wrench loosen the tappet screw 2.3 flats [the screw has 6 flats that the wrench fits on] & your valve clearance will be 0.016" [perfect]
Do this for both inlet & exhaust on number 1 valvesI usually mark the crank pulley with chalk top & bottom @ this stage.
Turn your engine clockwise 180* until the bottom chalk mark is now @ the top & adjust number 3 valves [the same way as you just did number 1's].
Turn the pulley a further 180* so the chalk marks are reversed & adjust number 4 valves.
Lastly turn the pulley another 180* & adjust number 2's valves.
All done in 5 minutes & I hope that description is decipherable for our European mates & some of the yanks.
Possibly will rock the king over the 20K too!