add to what? me, dumbguy, my mechanic, smart guy.
Solid lifter camshafts have a clearance specification given by the camshaft manufacturer.
The camshaft that I am using for example has a clearance given of .022". That is hot or more correctly with the engine at normal operating temperatures.
Now I happen to be running aluminum heads. Aluminum heads will expand when "hot" by .006" or more correctly when cold, they will be .006" smaller.
So the correct clearance to measure with the feeler gauge cold is going to be, .016".
Now an iron head will expand also and that is going to be about .0015". Using .002 is safe. So the cold clearance for an iron head with that cam is going to be .024". Got that part?
Next, you need to be able to determine zero clearance. You are going to insert the feeler gauge between the valve stem and the tip of the rocker arm. Then tighten down the adjusting nut just until you can no longer rotate the push rod with your finger tips. That is zero clearance.
Now here's the tricky part, IF you are using locking nuts with allen set screws in them, as you tighten down the set screw, you are going to open the clearance slightly. Enough to be able to rotate the push rod. The number is actually going to be about .001" of an inch.
Some will leave it there, but if you want to be dead nuts on, you are going to have to compensate for that by closing down the clearance with the feeler gauge another .001".
If you have got all of that, the Ford Shop manual has a specific order in which you adjust each valve. It's going to require you to use eight different positions of the crankshaft to adjust all 16 valves.
Some mechanics will tell you to throw that procedure away and just adjust each set of valves (1 intake, 1 exhaust) at top dead center of each piston stroke.
Now I've got to presume that Ford wouldn't have wasted the ink and paper to print the procedure on if it wasn't of significance. I consider it a text and the text as Gospel. If you want to be strayed by the dark side, I can't fight it's power. Do as you will. I go the straight and narow...on adjusting solids anyway.
Back in the olden days before electricity, racers could gain torque or rpm by adjusting the valves loose or tighter. Even if that works, you run the risk of snapping a rocker arm stud if it's too loose or burning an exhaust valve seat if too tight.
The normal inaccuracy you are going to have setting them at spec, is going to give you enough variation right there, so don't even think about this Vodo procedure of looser or tighter. Leave that to the Chevy guys who always needed to cheat anyway they could?
Oh, one other thing, specs are always given for an air temperature of 70 F. So if you choose to do this at 20 F or 100 F, expect some inaccuracies.
You are also going to get some people yelling from the cheap seats, booing as it were, that you need to do this with the engine running. Here's the word that you use with them. Poppycock.
Now go to it Pilgrim. Life's an adventure. So is adjusting valves. Let us know the new cuswords you invent while doing this. There's a good one I use after my finger tips are all raw and my back goes out from leaning over the fenders for too long. Decorum won't permit me to share those with you here.
Oh. There are at least two versions of the 289hp Ford cam that I know of. Different clearances spece'd on both.
...and sure you can adjust them hot BUT them things IS hot and you better have asbestos finger tips. Trust me on this point. Oil temp is 210-220. Your pushrods won't glow but your finger tips will. You can compensate for a lot of things but you can't fix stupid.