Following is a letter, used with permission, from one of our readers:
Here's a friendly warning for the new Johnson lifters appearing on the market. Instructions included with the lifters call for drilling a 3/16-inch hole for the adjusting pin 3/4-inch
from top of lifter housing in the engine block.
Ready to adjust the valves. The pin, a #8 penny soft iron nail, and the holes don't line up!
The holes in the block should have been 1-inch from the top of the lifter housing. The new lifter ports are .060" lower than the old Johnson lifters. Only a mild grind cam in this engine.
So, take the engine down and redrill the holes in the block. Clean drilling particles and reassemble.
Next, the adjusting screws are very tight on some of the lifters and adjusting the first one was so tight that a burr occurred from holding the pin. I could feel the burr turning the lifter adjusting nut in the housing. I removed all lifters and sanded the burr off and used a Dremel grinder to radius all very
sharp edges of lifter's ports and then a brass bar thru lifter's ports to give adjusting nut left, right 1/2 turn.
Experiencing this, I'll still use these new lifters. Hopefully this will help others be aware of this on the new lifters.
There are, to my knowledge, at least seven different adjustable lifters available now for our Flathead
They are not all the same and some are not usable.
One of the hollow adjustables now being sold has a Rockwell C hardness of 36. This is not enough to survive in service. A fine tooth file can be used on a bottom corner. If the lifter files readily, it is too soft. If the file "skates" and does not cut, the lifter may be hard enough.
To save some assembly problems you may want to observe some of the following.
Make temporary cam bearings hold
the cam so that you can check lifter location. You can use thin cardboard, like from a cereal box, to hold the cam in the approximate location. With the cam temporarily installed, put a lifter or two in place to see where the holding holes might best be drilled in the bosses. Try each bank, sometimes they are different.
After you have drilled and deburred the lifter bores and done all of the other block machine work, the block will need to be cleaned for assembly. After that is done,
and the cam bearings and camshaft is installed, assemble one intake and one exhaust lifter and their valves.
Turn each lifter adjusting screw a little to "break it loose" as Les did. Some new lifters have excessive torque values at first, especially if they have been stored a long time since manufacture. Set the valve lash on those two, holding the lifters from turning through the holes in the lifter bosses. I like to use an allen wrench. It is tough enough to not shear and
has that right angle "handle" to help get it in and out.
Remove those two valves and lifters. Measure each of the lifters overall length and preadjust each intake and each exhaust lifter to match. This is much easier to do on the bench than inside the valley.
Then, when you have put all of the lifters and valve subassemblies in the block, you should have much less adjusting to do and it will be with lifters that have had the adjusting screw turned.
Why does Les
tell us that the cam is a mild grind? He is letting us know that the cam has a near stock base circle and a smaller base circle is not the reason that the lifters are dropping down too far for the holes to line up.
If you do have lifters that have adjusting screws too tight, or too loose, return them to your supplier for replacement or refund. If the torque to turn an adjusting screw is less than about 25 inch pounds, it may not hold it's adjustment in service. Many of the new lifters
have torque values in the range of 50 to 70 inch pounds.
If you have lifters that are too soft, do not use them either. Return them to your supplier for a refund.
I believe that almost all suppliers of parts to our hobby are honest and are doing the best job that they can. Give them a chance to make things right and I believe that they will.
Thank you, Les, for sharing your experience with us.