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lokiminter 12-10-2010 01:31 PM

new and looking for help
hello everybody. this is my first post on any kind of forum so please be patient as I get used to the controls. I have a 99 grand cherokee ltd with a 4.7L V8. In the last year, I have replaced the radiator 3 times (feb,aug, and dec). after replacing it 3 days ago, upon restart, it is missing on one, maybe 2 cylinders and knocking like hell from the top end. It was running fine before taking it apart!
Aside from that, it has 200k miles and is probably ready for a rebuild anyway. I am completely new to jeep performance and don't know where to start. I would like to gain some extra HP during this rebuild but don't know where to start.... bore it? stroke it? cams? intake? headers? what kits are available? what have people had success with? what to stay away from? little shadetree secrets.... anything. I want people to say "WTF!" when a 5k pound SUV blows their doors!
thanks, Lenny

Frango100 12-10-2010 01:59 PM

Re: new and looking for help
Welcome to the garage.
What was the reason for changing the radiator so many times in such a short time?
This engine doesn't like to be overheated and the heads will warp when you let it to. Probably there is a leak in the headgasket. Don't know if you want to try to do someting with this engine before to decide to rebuild it?
If so, did you check for fault codes doing the key dance? ( 3 times the ignition key on/off and leave it in on after the last time. The odometer will show fault codes, or "Done" when all is ok.

lokiminter 12-10-2010 02:42 PM

Re: new and looking for help
the reason for all the radiator replacement was (as far as I can tell) just cheap radiators. the first one blew the seal at the end cap in feb, the 2nd began leaking where one of the flues was soldered into the end channel. and the developed a 1/2 inch crack in one of the flues.
My father and uncle have owned shops for over 35 years and I went to the normal checks for head gasket problem. no green residue on spark plugs (pulled all 8), no steam out exhaust, no oily residue in cooling system, no blow off or bubbles to overflow tank, no milky oil. they are suggesting the right cam gear jumped a tooth on the timing chain when I restarted it and the piston is now hitting the valve.
The truck has 200k miles on it but was still running like a scalded dog! running perfect and the check engine light has never been on.

Frango100 12-10-2010 03:48 PM

Re: new and looking for help
What i heard before is that one of the rocker arms sometimes can be off its place, not opening the respective valve and giving the misfire. Maybe good to check both heads for this first.

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