Please help ID this knock - movie link attached

[92DripCherokee]

I hear at least two distinct sounds, one grinds like a loose timing chain against the tensioner, the other knocks at the tempo of a piston stroke.

If that continous scraping sound was coming from a main bearing, it wouldnt for long.

My motor sounded a lot like that when it went bye bye.

 

[skipc]

I figured the rings too, and a deglazing... So, all the pistons and rings = the minimum?

I've done a valve job on a 65 Ford V8. It wasn't rocket science, but I can't say it was all fun... Can this piston swap be done in-car? What's the hardest part?

Just in case I have to go that way....

 

[gone postal]

I hear at least two distinct sounds, one grinds like a loose timing chain against the tensioner, the other knocks at the tempo of a piston stroke.

If that continous scraping sound was coming from a main bearing, it wouldnt for long.

My motor sounded a lot like that when it went bye bye.

The motor sounds noisier in the clip than in person. The knock is definitely evident in person and the high pitched noise I think is just the rockers - camera was only inches from the valve cover. It's possible that you hear a chain though - it is 170k old and I'm sure it needs a new one.

The knock sounds like it's to the tempo of the rods to me too. So, when the previous owner said it had a rod bearing going out I believed him. My understanding is that rod bearings don't usually show up at idle - this is constant - hot, cold, idle, cruising. I hear it more on cold idle than hot cruising though but that could just be the road noise & wind overpowering it. Supposedly it's been like this for over 2yrs. Also, if it were a crank bearing, that usually quiets at cruising correct? I don't think it's either though b/c I have good pressure.

Guess I have to pull the pan. I have a 3" lift - will I be able to pull it w/out dropping the axle? I've also never been inside an engine before - what exactly am I looking for. A broken/cracked skirt would be obvious, but how much play should rods, timing chain, etc have?

Go figure, I get a cheap Jeep w/ great pressure and no apparent loss of power and may still have to tear down the engine....:banghead:

 

[ParadiseXJ]

Has anyone said water pump?

I know it's loud but you said that the movie noise is louder than it really is. My WP made a similar sound before it went. That may also have something to do with the overheating issue. Check the weep hole. Any leaks? Any crap in the coolant?

I'd start there before I went in to the pan, as you said your pressure is good.

 

[gone postal]

Has anyone said water pump?

I know it's loud but you said that the movie noise is louder than it really is. My WP made a similar sound before it went. That may also have something to do with the overheating issue. Check the weep hole. Any leaks? Any crap in the coolant?

I'd start there before I went in to the pan, as you said your pressure is good.

It wasn't suggested, but I was thinking water pump myself. I know radiator was flushed and new thermostat and it still overheats, so I'm guessing I have either a bad fan clutch or weak pump. I was planning on a new serp. belt and timing chain, so I figured while I was in there I'd do pump too. If the noise is still there, then I'll decide whether I want to do a compression check or just pull the pan. Im not stoked on doing either though...

 

[JJacobs]

Rod knock shows up loudest on initial cold startup and cruising about 30-35 mph. Very light throttle, just enough to maintain speed- then feather in and out a little and you'll hear the rod bearings if they're bad. When the pan's off, don't pay any attention to rod side play, the pressure's OK so you know that's probably not an issue- the problem'll be in the overall inside diameter of the bearing. Pull a rod cap or two, push the piston up a little bit and look at the upper half of the bearing. Copper showing is bad, gouged copper is worse. Make sure to put the cap back on the same way it came off and torque that sucker!

It still doesn't sound like rods to me, though, unless the bearings have spun and it has 2 days to live.

 

[ghettocruiser]

Just sounds too heavy to be rods...but it could very well be. and it sounds like only one point making a noise. Checking the water pump is easy. Just pull the belt and spin it by hand.

I just put new bearings in a 97 ZJ that lost oil pressure while I was driving. Had a bunch of ticking and what not, and the motor had a slight very quiet knock before I worked on it. This is what my rod bearings looked like... And these are from a 127k mile motor. So this damage wasnt due to lack of oil pressure. If those are his original bearings with 250k on them, I can imagine they are alittle loose.

Copper looking ones are the tops obviously...

The sound that he has sounds much heavier like two objects are hitting each other during a cycle. But like everyone said, the video can be decieving.

J.

 

[gone postal]

ghetto - I followed your thread vigilently. I thought I may have to do the same thing, but then when I replaced the oil pressure sender the other night and realized my pressure was good I thought otherwise. That's what made me want to do the video and poll for opinions.

Good idea on removing belt and spinning water pump - hadn't even crossed my mind!! I always tend to overlook the super easy way.

I rarely drive this vehicle b/c I live so close to work (3 blocks), but I want it to be reliable b/c I just bought a house and am moving at the end of the month and will then have a 5 mile commute. I did drive it today though b/c it was pouring rain and the knock is pretty loud - like the video - so it's not too exagerrated. I can also hear the other noise faintly, so I possibly do have a loose timing chain too.

 

[skipc]

I did scope the pump on mine and no ticking there...

 

[Matthew Currie]

I did scope the pump on mine and no ticking there...

Wiggle it and make sure there's no play. But usually a water pump will make a more irregular knocking. Yours is very regular, and really sounds as if it's coming from one piston or rod.

 

[theschwarz1]

If he has a bent rod, does that mean that a rebuild is in order, or would he have to swap out for another engine.
I am in the same boat (sorry to pirate the thread). I bought a 92 XJ that sat for a few years, Finally got it started and running but has a bad knock and it runs rough. Im going through all the normal maintenance items first, but am following this and other similar threads carefully to find out if its worth fixing or shouodlI just give up and part it out. It has an excellent body, and its a laredo. Would be nice to get it runing right without spending too much$$$. I know i have lucked out already.