Can a timing chain make noise????

[kirkandsylvia]

Yes it can...just ask me, I'll tell you all about it! It's not so much the chain that makes the noise...it's the valves tapping the top of the pistons when the chain gets lose as in stretched out and causes the cam to lag the timing of the crank. What I thought was a possible colasped lifter, or the dread of maybe a rod bearing going out, turned out to be about a 1/2" or so, give or take an 1/8" slop in the timing chain.
Now..has anyone had this problem before, and or has anyone changed a timing chain before on a 4.0? Any insight on this would be greatly appreciated.

[inVERt'D]

I've never replaced a timing chain on a 4.0, but they can be pretty common failures for high mileage OHV engines--some more than others. Oftentimes an old V8 that runs like crap really needs a new timing chain more than anything else. The pins get worn and they can "stretch" and even jump teef. If your valves are smacking the tops of the pistons, do not do that anymore or you will wish it were "only" a rod knock!

Look for a good Cloyes True Double Roller timing set if you want a good upgrade that isn't too expensive. Haven't looked into it for the 4.0s but they used to be real nice for the Ford and Chevy small blocks and such. A good metal geared timing set would be the shiznit, but pricey. As popular and common as the AMC I6s are, they just don't have nearly the aftermarket support of the Big 3 V8s.

[Guest]

When I had my top end done. They replaced the chain and gears. Got them from Napa for my '93 4.0. Seem pretty easy when he did it.

[chris142]

I've never heard of replacing a timing chain and gears on a 4.0L except when rebuilding it.

The 22R Toyota was known to have Chain problems though. The plastic chain runners break then the chain rubs on the inside of the timing cover untill it wears a hole into a water passage and dumps the coolant directly into the oil pan.

[inVERt'D]

The 22R is actually a great little 4-banger. I was unaware of the timing chain issue. I suppose I shouldn't have qualified my statement with OHV engines. Overhead cam engines have even longer chains (and often more of them) and the belts (where applicable) fail too.

[kirkandsylvia]

I've never replaced a timing chain on a 4.0, but they can be pretty common failures for high mileage OHV engines--some more than others. Oftentimes an old V8 that runs like crap really needs a new timing chain more than anything else. The pins get worn and they can "stretch" and even jump teef. If your valves are smacking the tops of the pistons, do not do that anymore or you will wish it were "only" a rod knock!

Look for a good Cloyes True Double Roller timing set if you want a good upgrade that isn't too expensive. Haven't looked into it for the 4.0s but they used to be real nice for the Ford and Chevy small blocks and such. A good metal geared timing set would be the shiznit, but pricey. As popular and common as the AMC I6s are, they just don't have nearly the aftermarket support of the Big 3 V8s.

Fortunately for me, my XJ is in garage with oil pan off awaiting a new timing chain. I have been driving it for a while with a slight tapping. This weekend it became more of a loud tapping or sounds of 3 to 4 squirles throwing their accorns at the cage.

[2blk2drs]

Check you harmonic balancer while you have it off. Sometimes the rubber will get old and let the pulley rub a hole through the timing chain cover.

[kirkandsylvia]

Check you harmonic balancer while you have it off. Sometimes the rubber will get old and let the pulley rub a hole through the timing chain cover.

Thanks for the advice. I am going to be looking at several things while I have the bottom end open. I have already examined the cam lobes to see if there is any unusual wear...which there doesn't seem to be. I also looked at the rod bearings to see if there is any slop on the journal besides the expected side to side play...and fortunately there isn't. I have also looked at each of the cylinders from the bottom side with piston in the compression stoke to see any wear, and it looks good. For 270,000 miles, she looks pretty good. If I had the time and cash, I'd just pull it and rebuild it. Any other things that I should look at while I have the oil pan off before it goes back together??

I am also looking for a timing chain to put in but I don't have that much to spend. Anyone have any suggestions? I am not opposed to putting a used one in with low ( lower than mine) miles on it? I havent had much time to price new ones, and being up here in Calico, it's not like I can just run down to the local auto parts store. Any suggestions?

[2blk2drs]

http://www.napaonline.com/Search/Res...+50038+2038004

the cheaper one is $25, dunno If I would want to go cheaper than that, and have to do it again.

[kirkandsylvia]

http://www.napaonline.com/Search/Res...+50038+2038004

the cheaper one is $25, dunno If I would want to go cheaper than that, and have to do it again.

Thanks for the info. Thats cheap enough for me!!:gun:

[Ol Man]

Any other things that I should look at while I have the oil pan off before it goes back together??

Do you leak oil out of the rear seal? That could be something to address.

[6spdYJ]

I had a tapping sound for a while. It turned out to be my exhaust manifold split the front tube completely in half. Check this out http://www.ineedparts.com/auto-parts...-manifold.html It's gone up $5 since I got mine. Abbove 3000 RPM this thing as amazing. The best price I found on the rear main set was at Autozone. They called it a conversion gasket set. It's by FelPro and saves about $12 over buying individual seals. Now for the question on timing chains, with the Cloyes, does anybody know how much lower your power comes in when you advance cam timing 4 degrees on the 4.0?

[kirkandsylvia]

Do you leak oil out of the rear seal? That could be something to address.

No I sure don't, but....it wouldn't hurt to change it now. Dropping the pan wasn't exactly the easiest thing to do. Is the rear a 2 piece seal?

[kirkandsylvia]

I had a tapping sound for a while. It turned out to be my exhaust manifold split the front tube completely in half. Check this out http://www.ineedparts.com/auto-parts...-manifold.html It's gone up $5 since I got mine. Abbove 3000 RPM this thing as amazing. The best price I found on the rear main set was at Autozone. They called it a conversion gasket set. It's by FelPro and saves about $12 over buying individual seals. Now for the question on timing chains, with the Cloyes, does anybody know how much lower your power comes in when you advance cam timing 4 degrees on the 4.0?

Does it lower the power curve in the rpm...or does it raise the horse power in the upper rpm range? I seem to recall advancing the timing on the cam in VW's to get more horse power in the top end. Not sure if it does the same thing in 4.0's. Good question. Might be nice to know the answer to that before I finish this project up.

[6spdYJ]

Advancing the cam timing only lowers the point in the RPM band where you hit peak torque. Retarding it helps on the top end. Advancing should help the taller geared crowd, while those runnin 5.38's on 26 inch tall tires would get benefits.
The rear main seal is 2 piece on the 4.0. It's really easy. The hardest part was cleaning out the oil pan.