noise from timming chain area...damn it!!!

searched but found very little on this subject....

I put a new remanufactured 4.0 motor in my 89 xj last year.Right now it has about 9k miles on it and has always had a marbles in a can sound from the front of the motor that up until now I wrote of as accessory noise.

Today I pulled off the serpentine belt and started it to eliminate the possibility of the water pump,belt tensioner,alternator and other accessories being the cause of the noise.The noise is definately still there and comming from the timming chain cover.

The crank shaft pulley is the original one that came with the jeep I reused it during the motor swap because I was running out of funds.Its got a wobble to it and needs replaced(been putting it off)it doesn't appear to be rubbing the timming cover...could this be the source of my noise?Can the crank pulley make this noise even if its not rubbing the cover?

If it is the timming chain its always been that way from day one with this motor.What could they have done wrong when they put this motor together to make this chain noisey?The chain was new and tight when I was putting the timming chain cover on the motor and the rubber guide was installed as well.Everything appeared linned up....is there a tensioner in these 4liters that I over looked?


Any input will be appreciated...thanks!!!

outlander said:

If it is the timming chain its always been that way from day one with this motor.What could they have done wrong when they put this motor together to make this chain noisey?The chain was new and tight when I was putting the timming chain cover on the motor and the rubber guide was installed as well.Everything appeared linned up....is there a tensioner in these 4liters that I over looked?
Any input will be appreciated...thanks!!!

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Did you notice if the cam sprocket bolt had the little spring loaded tip sticking out of the head? That can pop out, and be overlooked when reassembling the timing cover to the block. I don't see a "tensioner" on mine (all apart right now) only the black guide piece in the cover, and that has two deep grooves worn in it. Ordering one of those tomorrow.

dont really remember the spring...can you take a pic of where it goes and possibly one of the front of the motor with the timing cover removed??I'm wondering if the oil hole that supplies the timing chain with oil got clogged with silicone....
What does that spring do??
thanks man..

The crank shaft pulley is the original one that came with the jeep I reused it during the motor swap because I was running out of funds.Its got a wobble to it and needs replaced(been putting it off)it doesn't appear to be rubbing the timing cover...could this be the source of my noise?Can the crank pulley make this noise even if its not rubbing the cover?

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Yes it can, there is a oil slinger inside the cover, just a big steel ring, if the balancers not in all the way in will be lose and rattle.

Here's the pin sticking out of the camshaft bolt. The spring is behind it in the shaft of the bolt. From what I understand it keeps the camshaft from moving towards the front, as the pin rides against the little bump inside the timing cover. I also can see what John is talking about with the slinger, as there really isn't anything else right there that could be rattling around like that. Check those two items when you can and let us know, before I finish putting my engine back together....

Thanks alot man,I really appreciate the pic.
I was thinking that the reason that spring was there is to keep the cam from thrusting out....

I'm about 90% sure That rod and spring wasn't in the old motor therefor never got installed into the new motor...damn I hope this didn't screw up the cam/bearings.....I don't remember installing it:twak:

so would the absence of that rod and spring cause the marble rattling noise???Probably,huh??
But wouldn't the cam walk out and cause the bolt head to ride on the inside of the timing cover and eat through it fairly fast(its fairly soft aluminum) without the thrust rod and spring in place?You would think it would chew its way through in no time at all...just thinking out loud.....
I know what I'll be doing tomorrow....is there anything I should be aware of while taking off the cover and installing the thrust rod??What areas should I pay attention to ensure that this didn't cause any damage?How do I tell if it damaged the cam/bearrings?Should I put a new chain in there....incase it was stressed by the cam walking out???

Sorry for the what ifs and all the questions but I'm freaking out....

Thanks again guys.That what I love about this site!!!This is giving me motovation to scrounge up the cash to get my name in red...

outlander said:

But wouldn't the cam walk out and cause the bolt head to ride on the inside of the timing cover and eat through it fairly fast(its fairly soft aluminum) without the thrust rod and spring in place?You would think it would chew its way through in no time at all...

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I thought the same thing at first, but I guess the timing chain is tough enough to keep the cam from walking too far forward. For a while...Just don't know how long it can take that kind of punishment before the chain and sprockets will need to be replaced. I guess if you are going to open the cover, may as well pick up a new timing set anyway. I have searched for that pin and spring and so far no one online seems to carry it. I guess it's a dealer part.
Also, I think someone on here recently had pics of a cam that had been walking, and the lobes had a zig-zag wear pattern on them. That can't be good. Unfortunately, I don't think there is any way to check for whatever damage may have occurred from this missing pin, other than tearing her down...

Yea there's plenty of 4.0's in the bone yard around here so I'll snag the thrust pin from there....

I wish I knew who had the cam walk problem,I wonder if they forgot the thrust pin???
Anyone know who it is??

ok I'll look at that while I have the cover off.
I bet you were pissed that you had to go back into the cover for that oil slinger!!!Like I am after I'm pretty sure I forgot the thrust pin!!!(Thanks again for the heads up on that scca28 I owe you a cold one!!Shipping address??lol)
btw..What was the reason it was fitting loose???

outlander said:

Yea there's plenty of 4.0's in the bone yard around here so I'll snag the thrust pin from there....

I wish I knew who had the cam walk problem,I wonder if they forgot the thrust pin???
Anyone know who it is??

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If you grab one from the yard yourself, might as well take the whole cam bolt. It will be easier to get the spring out if you have the bolt soak in your favorite cleaning solution for a while. Mine was really gunked in there, soaked it in mineral spirits for a couple of days before I got back to it. Had my engine shop guy look at it, he says both pieces look fine, he's never had to replace the pins or springs. The spring looks like something you find when you take apart a click pen. If you try to pull it at the yard, bring along some sort of small hook, or make one from a paper clip or something. Like I said, it may not pop out like you would think when you pull out the pin.
I looked for the cam problem mentioned above, but did not find it. It must have been on another site, sorry. Did find this though: http://www.naxja.org/forum/showthread.php?t=86611&highlight=cam+lobes
Again, let us know how this works out for you. Good Luck!

Ok here's the deal
Got the timing cover off today and sure enough no thrust pin and spring:shocked:
I've got bigger fish to fry though because my cam is 180* out of time.....I knew I should've rebuilt it my self instead of going remanufactured(didn't have the facilities)...they installed the timming set wrong.Its actually a blessing in desguise because If I hadn't left the thrust pin out I would've never opened the timing cover up to investigate and find out that whoever put this motor together timmed it wrong!!!

Don't buy from these people:http://www.jeepenginesales.com/

I kept thinking over and over "there's no way it would run".I took the timing set off and noticed that there are two holes in the end of the cam.What they did was install the cam dowel in the wrong hole making it appear that the cam was 180* out....Had both myself and my oldman really scratching our heads untill I noticed the two holes in the cam.....Oh well.