Escaped Rocker Arms.

[Gaz440]

Hi Guys,
I'm Gary from Victoria Australia. It's my first post here so here goes....
a few weeks ago while driving home from work my 06 JK's engine suddenly died. It gave a faint knock before I shut it off and rolled to a stop, suspecting a broken timing chain, I then had it towed home.
I've finally got around to pulling the valve covers today and too my surprise I found 3 rockers were loose in the head, 2 on the right and 1 on the left.
What would cause this? It was I very hot afternoon (40°c or 104°f) but it wasn't running hot.
The oil was down a bit but nothing concerning.
Would a sudden lack of oil pressure let the lifter thingys pump down and give the arms enough slack to pop out?
Thanks for any advice in advance.
Cheers.

 

[KJowner]

Valves hitting pistons is often the cause of this.

 

[DadOSix]

Hi Guys,
I'm Gary from Victoria Australia. It's my first post here so here goes....
a few weeks ago while driving home from work my 06 JK's engine suddenly died. It gave a faint knock before I shut it off and rolled to a stop, suspecting a broken timing chain, I then had it towed home.
I've finally got around to pulling the valve covers today and too my surprise I found 3 rockers were loose in the head, 2 on the right and 1 on the left.
What would cause this? It was I very hot afternoon (40°c or 104°f) but it wasn't running hot.
The oil was down a bit but nothing concerning.
Would a sudden lack of oil pressure let the lifter thingys pump down and give the arms enough slack to pop out?
Thanks for any advice in advance.
Cheers.

You may find a stuck or collapsed lifter (lash adjuster) on each of the loose rockers.

Ddpending on your maintenance habits , and those of any previous owners, there is likely varnish or gum in a collapsed one.

Newer engines had rockers with smaller holes at the push rod end to force more oil to stay in the lifter.

The whole mess can be swapped out without pulling the heads. I did my 06 and 04 06 was running rough and slipped a rocker one cold winter nite. It already had newer rockers but background maintenance was unknown. So he got a full set of lifters that weekend.

 

[u2slow]

The lash adjusters are a common one. Several youtube vids on them. Cheap and easy job really.

However, I thought at first I had this problem, but i had dropped a valve seat instead. That caused the valve to not rise all the way and the rocker wobbled off. I had to swap the head.