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#6 piston gone

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Old 08-03-2014, 09:21 PM
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Default #6 piston gone

I have a 99 grand cherokee with the 4.0. I've had a knock for a few months and have always thought that it was a cracked flexplate well the other day it took a turn for the worse. Soon figured it wasn't the flexplate pulled the head and found this. Two holes in the cylinder wall and the piston is gone. My question is would y'all try to throw a piston rings and sleeve in it or call it done? Thanks
Old 08-03-2014, 11:23 PM
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Done. If it was a rare engine in a numbers matching car, yes I would try to save it. But this is just a clean slate 4.0 in a 99 WJ, nothing rare about it. I would find a boneyard engine and maybe freshen it up with new bearings, rings, and seals. You have to use an engine out of a WJ or TJ, a ZJ or XJ engine will not be a direct swap.
Old 08-04-2014, 12:00 PM
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^^ Exactly what Busted said, 100%. Generally, sleeves don't work well in a thin-wall cast block, anyway. Think about all the damage that steel did in the lower end. How badly damaged is your head?

Last edited by dave1123; 08-04-2014 at 12:03 PM.
Old 08-04-2014, 12:24 PM
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I wouldn't be surprised if the valve are damaged since the plugs was crushed .
Old 08-04-2014, 12:33 PM
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Yeah, and if the piston crown got caught at the top of it's stroke, the connecting rod may be bent.

Basically, the engine is toast.
Old 08-04-2014, 08:17 PM
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I was going to replace the rod too. It actually may be the end for the gc.
Old 08-06-2014, 02:50 AM
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Don't trash it because of a bad motor. What else are you going to buy for the price of a motor?
Old 08-06-2014, 07:50 AM
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You can get a motor for around 500 bucks and spend another 75 freshening it up a little. Way cheaper than buying a new rig with an unknown history and less hassle then trying to sell a broke Jeep WJ.
Old 08-07-2014, 08:55 PM
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What years will work 96-02?
Old 08-07-2014, 08:57 PM
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Or what years did they do away with the distributor?
Old 08-08-2014, 06:37 AM
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Hey, Busted! how many times do we have to go thru this?

They changed the motor mounts and oil filter location in '99 so any previous blocks won't fit. Just about every other part will work, some better than others.
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