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ctgriffi 06-15-2012 09:39 AM

Just trying to help a friend: valvetrain busted
This is a long story, but let's just say I've got some friends that are in a bad way financially (lost his job awhile back). They've got a 2003 Jeep Liberty Renegade w/169K that's been out of commission for 15 months; a CEL came on one day and a loud tapping started coming from the motor. Dealer wanted $4K for a new 3.7L, and that just wasn't doable. So, I said I'd take a look...

We towed the Jeep to my garage yesterday, and tonight I pulled the driver's side valve cover to find a serious mess: Four rocker arms bouncing around, one valve lifter just laying in there, and three of the four cam bearing caps were basically toast. Of course, there were chunks of metal all over the place, so I spent a lot of time trying to remove all the bits with rags and the shop-vac.

I'd really like to do whatever I can to help them out, but I need some expert repair advice! What are the options here? Can I install new rocker arms and bearing caps, change the oil, and cross my fingers? Are we looking at a new camshaft or even a new cylinder head? What to do?

Nobody's expecting this thing to get back to 100% again. They just need it to be drivable so 1) they can have transportation again OR 2) they can liquidate the vehicle and move on...

Sorry for the long post. Appreciate your time. I've got some photos I may upload later, if that'll help.

Frango100 06-16-2012 10:05 AM

Re: Just trying to help a friend: valvetrain busted
Not an expert on this, but just trying to think together. Any idea what was the root cause of all this mess? With all i heard sofar it looks as an oil feed problem at least to this head. The other cylinder head is ok? With the bearing caps toast, it will probably be the same with the head bearing side. Depending on the condition of the bearings, you probably have to change the head. How do the camshaft bearing surfaces look like? Are they scored or any signs of overheating (discoloration)?
If the problem was oil pressure related, you can have more damage at the other head or crankshaft bearings as well.
So you probably first have to find the reason for the malfunction and find all subsequent damage and then decide what to do from there.
Is maybe a junkyard engine an option?

scjeep4.7HO 06-16-2012 10:43 PM

With this much damage it's hard to not say professionally replace the head. many of the issues mentioned could have cause the issue and then it compounded or it could have been another initial problem altogether. Honestly at this point you could try to resemble it and see what happens. Hell in all honesty the damage it's more then likely already done, so why not. The bearing journals are probably trash along with the cam so you probably not going to damage something already trashed. Visually Inspect the the hydraulic lash adjusters (lifters) the three corresponding bores for damage and check the cam follower for damage and check the roller portion of it.

HTC Thunderbolt 2

ctgriffi 06-17-2012 07:18 PM

Re: Just trying to help a friend: valvetrain busted
Thanks for the help, guys. I've given it some thought and talked to some folks...I don't think it's worth putting any time/money into this motor. It's got 178K on it already, and I'm sure that a bunch of those metal chunks have made their way through and done more unknown damage. And, like you said, scjeep, it's not clear what caused the trouble in the first place.

Too bad, though, 'cause this is one nice-looking Liberty-Renegade. They're gonna have to come up with money for a used engine...or just sell the thing as-is for a few grand.

Thanks again for taking the time to read/respond.

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