I'll try to be brief and provide all the necessary facts for some diagnosis. Blew a head gasket a while back, had the heads redone, new lifters, new cam and put it back together. Took the car out for a drive after a break in and blew a freeze plug. Shut it down, replaced the freeze plug roadside started the motor and it ran fine for a few minutes. Started it an hour later and the lifter clatering was horrible. Took it home, tore it down to the lifters and found two collapsed lifters. Replaced them, put it back together and still had a gap on those two lifters that caused a ticking sound. Then I replaced the two rockers that deal with those lifters. One became fine and no gap existed, but the other one still had about a mm of play. I ended up getting another push rod, but haven't installed it yet. I don't know if it will be longer than the one I have until I do the install. I'm told that they really don't wear, but I'm not sure if that's correct. The oil pump gives me pressure of 30lbs cold and 10 or less when hot. Specs in the manual indicated the minimum should be 30 -35 and 15. I think I'll rebuild the oil pump next just in case I'm not getting the proper amount of oil pressure. Any thoughts or comments are appreciated. Thanks.
I would get that engine out of there and replace ALL the "freeze" plugs before spending another minute doing anything else.
Are the noisy lifters on the "end" (oil flow wise) of the rocker arm assembly? If so the oil journals may be starving them of oil! They may be plugged.
This is probably a silly question, but how do I clean those journals if in fact they are starving the lifters? I've got oil with zddp in there now with some seafoam. One of the lifters was on the end where the oil comes up and I know oil should be getting to that one. The other is in the middle of the rocker arm.
Ok now that you indicate it's in the middle or at the beginning, it should not be the problem. If it was blocked it would starve all the valves and rockers behind the blockage. To clean them you could have them hot tanked and then pressure washed!