Pulled the valve cover for what was initially a head gasket job.

pushrod #5 (back to front) was dislodged from rocker head

while replacing the rocker arms and pushrods i notice that rocker head #5 sits loosely on the spring/pushrod

an eye check doesn't detect a low-sitting spring, bent rod, or a screwed rocker arm

would this mean the lifter is bad, or possibly gunked up?

are there any treatments that can be done without pulling the lifters?

 

Not quit sure i follow you. got a pic?


Cheap lifter fix (some times works, some times doesn't)...idle some Seafoam or ATF in the oil. Or any really good detergent to break up sludge n gunk. then change oil

 

Are both the intake and the exhaust rockers like this on #5 or just one of them?

Do you have #5 piston at top dead center, compression stroke when you observe this?

You should remove the applicable rocker and rod and look down to the top of the tappet using a bright flashlight. See if the pushrod seat retaining snap ring has come loose or the seat is damaged, or both. Compare the postion of the seat in the tappet to another known good tappet as a reference to see if the seat is at the top of its travel. Normal lash/preload travel of the seat is about .040-.060".

If the pushrod seat/retaining ring are intact have a helper rotate the crankshaft at the crank vibration damper while you look at the tappet from above and see if the tappet moves freely. Place and hold pressure on a pushrod on the tappet while the crank is being rotated and see if you can feel the tappet moving up and down (compare to another tappet as a reference). Rotate the crankshaft two complete revolutions.

If the tappet up and down travel is not the same as a known good tappet, the cam lobe for that tappet may be worn.

If the tappet movement seems okay, and the pushrod seat and its retaining ring are okay, but the pushrod seat seems to be stuck about .060" down from the top you may want to try to free it up by pouring some Marvel Mystery Oil on top of the tappet and apply a pumping action to a pushrod on the pushrod seat to see if it will free up. If it won't it looks like the seat is stuck in position or damage to the internals of the tappet has occurred.

See cutaway of a hydraulic tappet (lifter) below.

 

Awesome right-up CCKen! As it so happens my #5 from rear is loose as well, probably 1/8" play.

 

yea geeky i measured it roughly with a ruler and it was about an 1/8" inch.

my writeup posted on jeep forums:
found a tip from cherokee forums, i poured half a bottle of seafoam down rod-hole #5, then torqued the rocker heads and then finished buttoning her up (not before having to reposition the f$%^ing intake manifold - redlined on first startup). It ran with a loud loud knock for about 20 minutes and then it went away, had to be careful not to put it over 2.5krpm or else the sound got worse. so fortunately for me my lifter was simply just gunked up, the same gunk that threw rod #5 in the first place. Now just to get an oil change tomorrow and beg for another 100k miles