Seabee73

I have a 2004 Grand Cherokee with the 4.7. A while back, I was driving to work and suddenly lost engine power. Limped it about a mile back home and started to tinker with it. Was told I could possibly have been a failed cat converter. Parked it for winter until it warmed up.
Warmer weather came. Pushed it into the garage. Unbolted the cat at the exhaust manifolds and tried to start. Just cranked and cranked. Pulled off driver side valve cover. Chain off cam sprocket and laying between sprocket and first bearing. Then noticed that both plastic chain guides were missing and a piece of the bottom guide was laying in oil passage.
Took off passenger side valve cover. Both plastic guides are there but top was missing the end piece and nowhere to be seen. Started to disassemble the front of the engine to replace timing chain then realized that valve and piston damage may be possible. The engine is a remanufactued with just over 50k on it. It's out of warranty.
What could have caused the guides to break? And how much internal engine damage could there be?

Willys55

if it jumped time, even by just a few degrees, the valves will hit the pistons. You will need to rebuild it or find a good running donor from the salvage yard. As far as those chain guides breaking, any number of thins could have caused it, they could have been compromised by extreme heat, could have been hairline crack when new, or worse effect would be over rev, but that is hard to do with the way pcm are programmed with rev limiters

Seabee73

Thanks for the info.