]hmm it seems i have overlooked some details. this is
it seems as though some of them have preload going on and some dont.
-Check post#9, and note TB says if the pushrods are the right length.
-You might want to look carefully at the pushrod cups in the tops of the lifters. You may find that in the loose ones, the cup is down further than in the tight ones.The reason for this difference is that the oil has gone out of them. To check this you have to treat the engine as eight --one cylinders. The best way to do this is to put a piston/ any piston at the top of its stroke, and on the compression cycle. Both valves will now be closed, and the lifters will be on the base circle( backside of the lobes). Now you look into the cups, as you grab the rocker arm and attempt to force the pushrod down into the lifter. If/when you find a loose one, it will push the cup down into the lifter, and the little spring inside it will return it as you release the rocker arm. The reason this is possible is because the oil has drained out of it. On those that are tight, the oil is still inside them. Next you rotate the engine 1/4 turn, to the next cylinder in the firing order and repeat the test. And so on.
-Now, this tight/loose business may all be normal. The trick is to prove it. Pick any cylinder, that has a piston at the top and is on compression stroke. And with all the valve gear installed. Now shine a light into the lifter, and observe how far down inside the lifter, the pushrod cup has traveled. To determine this, you will have to know what this area looks like, when the cup is fully at the top. From your previous post I think you already know this but Ill go into it anyway.So grab your chipped lifter and inspect it for that condition, then reinspect the one in the engine and compare.When you are confident that you see the difference, then you can figure out how to measure it.
-The whole reason behind hydraulic lifters, is they are quiet.They be quiet because they are self-adjusting. The way they are able to self-adjust is via the engine oil coming inside them, under pressure from the oilpump, and pushing that little pushrod cup up against the pushrod until all the slack has been eliminated. Of course if the cup comes all the way to the top, then there is no longer any adjustability left in the system. So we as builders, and modifiers, have to engineer the adjustability back in.We do this by adjusting the pushrod length. The length needs to be long enough to push that cup down far enough that the adjustability will last at least until the next rebuild.
-Now getting back to the measuring. I use wire feeler gauges. The kind that are used for measuring sparkplug gaps. Just start sticking them in there one at a time, from biggest to littlest, until something fits. That number is called the lifter preload.Again Im sure you know that already.You may not be able to measure them all with used or in-service lifters, because some of them may be full of oil.If you let them sit under spring pressure, sooner or later they will bleed down.Some take minutes, others hours or even days. So if you really want to measure them all, you will have to force the oil out. If you can spin the pushrod its loose enough to measure.If all your parts are unmachined, I see no reason to check more than a couple or a few. On the other hand, if the heads or decks have been cut, then I would check, as another poster recommended, at least the 4 corners of the assembled engine.As to lifter preload, I did a search and the numbers are all over the place.( from .005 to .080, and even .100 was mentioned).I guess I cant help you with that at the moment. If I had to voice an opinion,on a roller lifter I should think .020 to .040 would be plenty.Your p-rod supplier might be able to give an accurate number. Perhaps someone else will chime in.
-I have adjustable rocker arms, so set my preload almost right at the top, a half turn on the screw, maybe .015 ish,, knowing, as the valve-train parts wear, I will have to readjust them, occasionally.
