lifters don't plunge??

[maddux31]

I installed new cam/12 new lifters when I rebuilt my motor 1,200 miles ago and had an overheat/head gasket failure.  Tore the motor down again this past weekend.  Discovered that one of my lifters was still dry at the orifice feading the pushrod on the intake/#1 cylinder.  Pushrod was also dry.  I bought a new lifter due to the one that was seized up, it is a GM part.  This particular lifter (GM) plunges when moderate pressure is applied to the top of it.  The other 11 lifters (sealed power/federal mogul), do not plunge even with 3x as much pressure applied to the top of them.  The two different brand parts are identical in appearance.  When I installed the 12 lifters on the last rebuild I did not check the amount of pressure needed to depress the plungers.  I do know that they would move because when I   tightened the rocker retaining nuts down I remember a couple of the lifters on the "up" stroke were allowing their plungers to depress when torquing rockers to specs.  My question is how much pressure should it take to depress these plungers and should I pay 3x as much to replace the "hard' plunging sealed power lifters with the "easy" plunging GM lifters...... can't wait for GMpartsdirect to ship because I have to have this thing running by Fri.  Car ran fine with the lifters in for the 1,200 miles-- no lifter noise at all.   TIA Dale Malcolm.  Omaha, NE.

[Chris A]

The other 11 lifters are probably primed/pumped up, so they shouldn't depress easily unless they are worn.

I would chuck up an oil pump rod in the drill and run the oil pump with oil in it to make sure everything was getting oil at this point. I wonder if the galley is clogged or the lifter was clogged. Surprised it didn't fail catasrophically with no oil in it.

[maddux31]

The other 11 lifters are probably primed/pumped up, so they shouldn't depress easily unless they are worn.

I believe the lifter is defective, did the drill thing earlier today and all is well.  The oil had been changed at 200 and 500 miles due to the rebuild and  also had a 1/3 pint of E.O.S. in it.  Helps prevent friction.  Upper engine had plenty of moly in it when I started the engine up also.  I didn't know how much pressure these lifters have in them when primed.  Do you spray your head gaskets when you set your heads, or do you set everything dry.  Just curious because I've heard different methods from different people.  Thanks for the info on the lifers, Dale