Well I went to start my Grand Cherokee up one day late in April and while backing out of the driveway - BAM!!! Sounded like I put a rod through the damn block!

102k miles on it - maintained to the hilt and BAM!!!

So anyway it took me about a month to dig into it (removing the heads on a modular OHC engine is a b*tch to say the least). This is what I found:




What had happened was the valve seat on cylinder #2 dropped out of the head and took out the piston, broke into pieces and the pieces went up into the head - up into the intake manifold and took out the other head!

So the heads went to a local shop for a total rebuild and got ALL NEW valve seats and one valve on cyl. 2.

Decided rather than just rebuild cylinder 2, I'd to a TOTAL REBUILD and bought an over-haul kit from Rock Auto. So by late May I started to strip the entire engine down to the block - save the crank shaft (which is forged on a 4.7 HO engine so it was fine).



Started the rebuild around the first week of June and by the end of June I had this with all 8 new pistons in place:





Got the heads back and today I finally got it together enough for a "test crank" and low and behold - the thing fired right up! I still have some work to do to button it up and have to figure out how to fab up some re-mounting up front to get a couple of pusher fans I bought to fit and have some re-wiring to do - but at least it's running!!!



To those of you with Chrysler 4.7 V8s BEWARE - the Jeep forums are filling up with guys who have dropped valve seats and we are finding a lot of guys with 4.7s that are getting some age on them starting to report the issue on this forum!!!

 

Good to hear its back together and running.. That piston looks just like the 2 that came out of my old mans Hemi.

 

Yep, sadly I'm finding out that ALL aluminum head engines developed by Chrysler during Daimler (Mercedes) ownership are prone to this. Usually it happens after an over-heat as the aluminum heads expand and the steel seat(s) drop right out - but not always. My Jeep NEVER got over 220* and that was just once when my radiator split.

I'm hearing every day across multiple forums of 3.7, 4.7 & Hemi engines dropping valve seats. Even the new Pentastar V6 is having the issue and I've seen some with as low as 20k miles lose a valve seat! Great - I have so much damn money invested in my Hemi - but at least I have a 180* thermostat and a big a$$ e-fan and it NEVER even gets up to 195*, even when towing - but it's always going to be in the back of my mind now when I drive it...

So the final $$$ tally is as follows:

Heads rebuilt with new valve and all new valve seats - $500
Rock Auto complete engine over-haul kit - $800
Mopar water pump and hoses - $200
NGK Platinum spark plugs - $60
Two 7" 1550 cfm pusher fans - $40
Labor for a friend who used to work at a Jeep dealership who helped me for about 8 of the close to 30 hours I had in this ordeal when I was stuck or unsure of what the hell I was doing - $250
New battery - my ORIGINAL 10 year old battery finally died while the Jeep sat for about 3 months and won't take a charge - $80
2 bottles of purple ice for the radiator and HOAT coolant - $ 50

I think that about covers it at $1980...

BTW I know a guy locally with an '01 4.7 who had the same thing happen who took it to the dealer. They ONLY replaced the one head on the side that dropped the seat with a re-manned one and only rebuilt the one cylinder that failed (as opposed to the TOTAL rebuild that I did who soaked him for $4400!!! We also have a Ram member (4.7 also) who pretty much had the same thing happen and the same repair who paid out the wazoo too, I don't know what his final bill was.

 

good post Hammer, your Jeep is a H.O. right? If this ever happened to me I think I would look for a H.O. 4.7 with 60k on the clock or so..I wish mine wasn't the 230 HP model

 

Good luck with that. When I started exploring my options I first looked into picking up another HO. There was ONE I could find and it was like 1400 miles away, had 140k miles on it and the guy still wanted $3200 for it!
Regular PowerTech 4.7s are all over the place and I found re-manned ones with warranty out there for as little as $1800, but not HOs.
I would have had to change PCM and wiring harness to go to a regular 4.7 and lose 35 HP & TQ which I really didn't want to do. Rebuilding this one cost about the same/maybe a little less than picking up the cheapest regular 4.7 I could find.

I even thought about parting my Jeep out, but really didn't want to as it's in pretty much mint condition. I did have a LOT of inquiries on Jeep sites for my Dana axles due to the lockers in them, had a guy want my 3" over-size coils and one guy wanted my power leather seats though...

 

You forgot the beer tally. Nice rebuild!

 

I've gotten a lot of PMs here and on a Jeep site about the kit I used. It's a Rock Auto kit but RA wanted $1100 for it and I found it $300 cheaper on ebay - funny thing was the kit was dropped shipped to me right from Rock Auto, LOL...

 

sooo ur saying i better get a good efan and 180 stat on my 4.7....

 

Well I had a BAD weekend! Jeep left me on the side of the road on my way to work. Cylinder 7 died and when we removed the valve cover found a valve had snapped clean in two and a rocker was broken 140 miles on my rebuilt and supposedly certified heads!!!

I'm fixin' to see what the shop who charged me almost $600 to rebuild the heads has to say. This one may end up in court if this shop doesn't do the right thing!!!

 

Since getting the re-manned, re-manned head back the Jeep was not running as before. No CELs or major issues but just not quite right AND it wanted to stall at lights and stops signs unless the A/C was on to bump idle a little. With the A/C off it wanted to stall unless I kept one foot on the gas and one on the brake and just fed it enough gas to keep idle up about 200 rpm higher. To be honest, every time I got behind the wheel I got the uneasy feeling that the other head was gonna fail on me and take my entire lower end rebuild out with it and leave me with a hunk not worth selling.

So I just got fed up with it and put it up for sale. Asked $7000 and figured to take the first offer of $6500 which netted me right at $4000 after I pay off the credit card with the engine rebuild cost on it. I was straight up with the buyer that I just completely rebuilt the engine and he was satisfied with the compression numbers we pulled before the re-manned head issue - what I did not volunteer was that the re-manned head failed and had to be rebuilt a second time - but I gave him all the time he wanted to check over the Jeep.

Hated to sell it BUT I could not afford a daily driver that I could no longer rely on. The thing made me late for work twice now and that's enough. Took the $4000 I netted and put it down on a 2013 Hyundai CUV which is rated at 34/28 mpg. Just your basic commuter front wheel drive 4 cylinder but don't worry - I still have my lifted 4x4 truck for my outdoor activities.

Other than about an eight month period right after my divorce this marks the first time since 1993 I will be without a Jeep product in my driveway.

One last pic for prosperity: