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Tick, Tick, waiting for BOOM

PoopJeep

NAXJA Forum User
1999 Cherokee Sport Auto, 145,xxx miles, Oil changed regularly, 3" R.C. lift

I know there are many threads regarding flex plate & lifters knocking. Today at about 7 am i started my 1999 Cherokee Sport, backed out the driveway and put it into drive. About 20 yards down my road i start getting a sweet knocking. I has lightly knocked before so i figured possible dry start + the fact i havent driven it in a day ish. Further down the road it became more pronounced. I stopped double checked my oil and i was okay and put in some lucas (i know its frowned upon but its all i had) and still the knocking continued. All the way to work which is about 50 miles so idk what kinda damage i have done already but ill now describe the knocking.

I have audio but it was from my cell phone so obviously its not HQ but i also do not know how to add audio for you to hear. The knocking sounds basically like the slight knocking i had before but more pronounced. It was hard to tell where exactly it was coming from because it tends to echo in the engine bay. It sounded as if it was coming from my valve train because it seems to be 2x as fast as idle. The metal tapping would increase with engine RPM and speed. If i let off the gas for a split second it would be silent and then as idle came around it would tick with idle.

On my lunch break i took it to autozone because a friend with a jeep works there. He grabbed a stethoscope off the shelf and took a look/hear. He went through cyl by cyl until he reached the back of the engine. He said most likely a lifter has colapsed or bent valve etc etc. He and I talked about draining the oil and running about a gallon of diesel in the motor for 10-15 min to see if it would release a possibly stuck lifter so i did it. I then drained it out (hot as h*ll by the way) and then refilled with GTX high mileage with a K&N filter. No luck. On a side note i did mistakenly put on a fram oil filter roughly 2k miles ago when i did my oil maybe i did my self in idk.

My brother towed me home from work because i was afraid to do any more damage that i may have already done (he has a ford so that was depressing enough for me.) After putting my second car on the road that i hated doing (summer car thus the jeep for winter) i pulled the jeep in the garage and took off the valve cover. There was no scoring on the valve cover or any of the rocker arms. The bolts i will say were "loose" on the end cylinder (the back back one). I removed the rocker arms and checked for unusual scoring or anything and nada. The push rod from the last last (furthest one in the engine) rocker arm seemed out of place so i re-seated it. After checking everything i bolted the rockers back down to 10-Nm and the furthest rocker arm seemed to depress more compaired to the others. Again i have pictures but they dont really show much but ill add them anyways. I was hoping i worked wonders but after starting the jeep it played a nice little snare drum solo.

I have not checked the flex plate thing yet nor do i know exactly how (write up or pictures would be sweet) but if that might be my next step so be it. The only reason i went with the valve train first (and it still might be the issue) is because between the stethoscope and what i hear about flex plates making noise primarily at idle i assumed i was logical. Although when i crawl under the jeep it sounds almost identical. If anyone can help point me in the right direction i would appreciate your help greatly.

Cant post pics because i forgot my photobucket password & it locked me out it just gets better and better but i will admit to me the photos looked useless
http://www.youtube.com/watch?v=-vIg3OFL19A&feature=related

this video i found on you tube is IDENTICAL! to my noise...

anyone?

anyone?
 
get yourself a cheap stethescope and add a length of hard tubing to it so you can point it into small areas. listen to were the noise is actually coming from. thats a loud knock. much more than a stuck/dry lifter imho. maybe a broken flex plate, or even a rod bearing broke loose. whatever, first you need to locate the source or atleast as close to the source of the noise as possible. heck even a shredded surpantine belt can make a knocking noise like that. just do yourself a favor and DO NOT rev it like the guy in the video did. OMG. :tears:
 
i did use a stethoscope. and it lead me to the back of the motor. but sound can travel through solids so i worked from the top down. i realize it didnt find it spot on but it pointed me in the general direction and the stethoscope didnt make much audible difference as long as it was in the rear or the motor. what should i do that i have or havent already done? remove the springs for the lifters? rockers? push rods?
 
I've heard of power steering pumps on the newer ones making an incredible knocking sound. I know a guy who bought one because the previous owner took it to the dealer about a knocking noise, they told them they needed a new engine. They sold it to this guy for about $500. He got to messing around and found it in the power steering pump, the little piston in there was slamming around. Grabbed a p/s pump and put it on and it's now his daily driver.

May not be your problem, but it might help you out :)
 
I appreciate your help but the whole stethoscope thing pointed me to the rear or the motor. it sounds the same above & below the jeep but also its just quieter inside obviously. thats why im going to attempt felx plate tightening tonight but for the amount mine was knocking im sure the things toast. now i gotta find out how to drop my trans an replace one before ma dukes returns from the D.R.
 
from what ive heard, the flexplate breaking is a common problem. and apparently the break right at the mounting bolts to the crank. not easy to see even with the inspection plate removed. but with a tiny flash light you may be able to see much better, i just didnt have one when i inspected mine. i dont have a knock, but more of whine like a bearing running dry. but only in gear and under a load. im betting yours is a full break of the flex plate at the crank. my buddy said his sounded like that and thats what the problem was with his. good luck.
 
On my lunch break i took it to autozone because a friend with a jeep works there. He said most likely a lifter has colapsed or bent valve etc etc. He and I talked about draining the oil and running about a gallon of diesel in the motor for 10-15 min to see if it would release a possibly stuck lifter so i did it.

Might not want to listen to that guy anymore. That sure didn't help your engine any.

I've pretty much given up on trying to diagnose engine noises over the internet, it's just too hard to make out what's going on. Nothing at all like actually standing there listening to it. Your best bet is to have someone knowledgeable take a listen.. and sorry to say, but that's probably not gonna be an AutoZone employee.
 
Looks like the piston skirt came apart . I would start looking for the cause possibly from age or detonation or a slight hydro lock
 
aint that bad, mine let go at 5k, #6 pistion blew apart, pieces of it were in the intake and even a couple pices in the #1cyl
 
Might not want to listen to that guy anymore. That sure didn't help your engine any.

I've pretty much given up on trying to diagnose engine noises over the internet, it's just too hard to make out what's going on. Nothing at all like actually standing there listening to it. Your best bet is to have someone knowledgeable take a listen.. and sorry to say, but that's probably not gonna be an AutoZone employee.
Agreed, though I suspect the "gallon of diesel" was a gallon of diesel engine oil... I hope anyways! That might actually help due to the heavier concentration of detergents in diesel oil (iirc) and wouldn't be anywhere near as bad as running diesel fuel in the crankcase.
 
Probably some rule that you can't post there until a certain amount of posts...
 
I think you can't post in the national for sale sections without being a full paid member, but I'm not sure. Your local chapter (probably NAC based on the location you have listed) probably allows posts however.
 
got some good news and some medium news. The piston heads look great, the cylinder walls also look great. no scoring at alll. the piston skirt went kablamo and as a result the sleeves are starting to join the club. I havent pulled off the crank yet but im hoping that it is simply just a swap of the pistons and ill be good. I will hopefully get around to removing the crank tomorrow night or friday night after work and check the journals for crapola etching etc etc. For how clean my valve train and cylinders and pistons look im very curious why the skirt decided to blow off. maybe it was prom night in the engine and cylinder 6 was a slut idk
 
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