knock knock

92 4.0 with a discernable knock.

speeds up with increased rpms but does not get 'worse'.
pulling plug wires does not cause a change.
had the cracked header repaired.

does not go away under load.
checked the flexplate bolts...ok.
does not get better or worse with increase rpm or decrease.

any ideas?

thanks

How is your oil pressure looking? At cold idle, hot idle, etc

Hard to say without hearing the "knock" is it a low end knock, if not maybe something as simple as an exhaust leak or loose spark plug

oil pressure starts out at 50ish cold then drops to 20ish warmed up.

plugs are tight and repaired the exhaust leak.

here is a poor recording:
http://s2.photobucket.com/albums/y16/ChipsXJ/?action=view&current=000_1316.flv

WOW---That sounds like no oil getting to the top end.

pulled cover before lunch.
will check push rods after lunch.
check rockers for obvious type damage?
anything else while I there?

getting oil......how much should it be getting? should it be splashing all over the engine compartment at idle?
it is not....just kind of running off top of the rocker and down into the pushrod channel....not strong though.

all push rods straight, no obvious damage to fulcrums or rockers.

I noticed some pusrods missed going onto the lifters by just sliding them into the pushrod hole and I had to 'find' the top of the lifter to rest the pushrod in........is that normal?

could it be lifters?

just about ready to swap the motor out.

anymore ideas?

I was going to pull the engine and swap in another 4.0 that I have in a donor XJ.

I might go ahead and pull the head tomorrow and look at the lifters......since I am going to pull the engine I would be tearing it down anyhow at some point..........what does a 'collapsed' lifter look like?

I read somewhere that it would be identifiable by a loose push rod. all pushrods seemed tight.......but I could twist some of them pretty easily...is that normal?

and will I need to do anything other than swap in new lifters if that is the problem?