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Timing Chain

srpope80

NAXJA Forum User
Location
Tampa
After pulling the oil pan on my 2001 Limited XJ 4x4, I examined all of the piston skirts, etc, and found them to be very much healthy looking and intact.

What I did find, I *think* is quite a bit of slop in the timing chain.

I could push the chain around very easily from the bottom of the oil pan opening with my finger.

How much is too much play in the timing chain? Could it make this sound? (My video)

http://www.youtube.com/watch?v=vDOyZwH1Fjc

Thanks! Love my Jeep.... Want it to live a long long life after I rescued it from a buy here pay here lot!

-Scott
 
Bump!!

If anyone has any information how much play should be in a '01 4.0 timing chain, I really need to know. I don't want to rip off the timing cover to find out that isn't the issue...
 
The timing chain should be taught. You will need to remove the cover to check the chain and related parts. Timing chains do stretch but there could be other issues also.
 
What I would have done first was grab a piece of wood, put my ear up to one end and poke around various parts of the motor (carefully) with the other while it was running. (poor man's stethascope). Noises like that can travel a long way from where they originate from and really throw you for a loop. Using the wood helps to eliminate other noises that may or may not be influencing the bad noise.

Off topic here, is that a meguiars car wash soap bottle in place of where the coolant overflow bottle should be? Did I see that right????
 
I used an old broom handle and it did appear to be coming from near the front but higher on the driver side where the timing chain would be... Couldn't really pinpoint but I'm going to try and get a video of the chain movement. It's pretty sloppy with just a tiny bit of pressure from an index finger.

About the Meguirs Car Soap bottle; yes; the old overflow was cracked and that was my poor mans bottle until I bought a new one. I used my extra cash to buy a new radiator. I guess I'm the only person who goes to a buy here pay here lot and has a Jeep towed home to save money..... :D
 
Why did you pull the oil pan ?

Specifically, where is the noise coming from ?

Have you checked the Flex Plate bolts for proper torque ?

A loose timing chain doesn't make that type of noise. How is it you have determined the chain is loose ?
 
When I rebuilt my 88XJ at 385,000 mi, I replaced the chain with a roller heavy duty chain. Loose chains mean they're stretching. If it were my Jeep I'd replace the chain with a top quality roller chain or gear drive.

Depending how much work you want to do, a re-ring with top ductile rings (unbreakable) or the latest stainless steel top rings (also unbreakable) is a worthwhile effort (good quality ring sets cost about $100). Why change rings? If a brittle plain cast-iron ring breaks, it can break the piston, and score the cylinder walls, etc.. The rebuild then becomes very $$$$$$$$$$$$$$$$. Over the years I've had too many broken rings in all types of vehicles. I've learned my lesson with plain cast-iron rings. I seem to recall one of the Jeep books recommending re-ringing new engines before plain cast-iron ring breakage.

Best regards,

CJR
 
Tim, I pulled the oil pan to check for "piston skirts" that have broken. Everyone pretty much said that would be it, but it's clean as can be....

No cracks, breaks, etc.

I have checked the torque on the flex plate, and it is good. I can push on the chain and make it flop up and down pretty well... That's pretty much how I determined it is bad. It can be moved side to side also.
 
Just my two cents - your timing chain may need replacing if it has a lot of slop in it but that is not your noise. I would look to the valve train. Take off the valve cover and see what you can find.
 
Cloyes makes a double-roller replacement, Hesco offers a single-row similar to the earlier HO engines. Both are over $100 so brace yourself. The only thing the 'silent chains' ever did was cut production costs and marginally reduce noise from under the hood. They begin to stretch immediately.

IMO, money well spent on a rebuild or refresh in your case.
 
The single roller that Hesco sells is just a standard single roller with bushings for timing offsets. Not worth the price, IMHO. Cloyes and Rollermaster/JP make a double roller and the latter has a billet gear.
 
No that does not sound like the timing chain to me. Could be just about anything rattling, something in the exhaust, a noisy valve train (lifter, is very common in Jeep 4.0s), hell I had a harmonic balancer making that noise once as the rubber in the HB came loose, and slapped the fan blade, same for an exhaust leak at the doughnut, and noisy tappet / lifters, which I lived with for 6 years, until I learned to run the engine at 3600-3800 rpm for 1 minute after warm up to free up what ever was sticking in the valve train. Try running at 3800 rpm for 1-2 minutes after warm up. If the noise goes away (it may come back, or come and go, I had to do the 3800 rpm trick several times, especially in winter, to get rid of mine), it is in the valve train, probably a lifter issue.

Could be a busted Cat converter....also look for loose parts, every where.
 
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After spending some time under the Cherokee this weekend, I'm even more at a loss. Here are a few things I have found:

1. I can't pinpoint any noise to a particular area. I ran the engine with the oil pan off for a few seconds, and it does sound like it's coming from the upper piston, lifter, area.

2. I checked all the cam lobes by spinning the engine over, and they look good and the lifters feel tight. You can reach up and grab each one when the lobe is down and they would not move, etc.

3. The connecting rod end caps seem loose to me, but I'm not an engine teardown pro.... You could slightly wiggle them side to side, but this is not where the noise sounded like it was coming from so I don't think it's that.

4. With the coil pack removed, I turn the engine over and I could not hear any noise with the starter engaging. This leads me to believe it might be wrist pins since it only happens in combustion. When I spin the engine with the plugs in or out, no noise is present...
 
3.Your rod caps are loose??! I really do hope you mean the whole rod. If not, you might want to retorque the rod cap bolts.
 
Every one of my rod caps can be "slightly" moved side to side inside the counterweights. They are all uniform in movement. Motor has 125k on it, but I am unsure of the previous life it led.
 
I mean the whole rod... Grabbing the end cap you can wiggle each one (uniformly) side to side between the counterweights... I thought it would be very tight but I guess not.
 
FWIW, many 4.0s have that noise for 100's of thousands of miles, and just keep running. Mine sounded like it weas going to throw a rod at one point, but just holding it 3800 rpm for 2 minutes fixed it. That was 2 years and at least 10,000 miles ago. Before that it was a cold weather start up knock for 5 years. It has 278,000 miles on it now. the 89 finally started making that noise briefly last winter, and pushing the engine to 3800 rpm fixed it too.

MMO oil seems to help too. Some people reported issues, noises, that came and went with different brand and wt oils. many think it is a lifter issue, inside the hydraulic lifter.
 
Listening to your video ,my 87 sounds sorta like that but goes away after warm, I was told was rod bearing..nope just did them and they were perfect and all in spec with plastigauge. Mine is right by distributor area, I also have no broken piston skirts,burns no oil, no smoke etc . Has 165 k miles. I thought. Wrist pin but from what the eng rebuilder says is wrist pin noise will not go away warm ? Anyone heard of distributor noisy when cold ? Plugs all burn perfect too .
 
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