Major Timing Chain Rattle!

[Well Whoop De Do]

I just rebuilt my KA24DE. I started it up and it ideled at about 1200 RPM. Normal?

Well the engine ran smooth except for a major rattle from the top of where the timing chain is. It comes and goes. And the from the front of the motor you could hear the chain moving. It makes the shoooosh sound really loud. I have taken the front off twice since then trying to fix the rattle and I can't! The timing chain is on right! All the marks line up, it's running smooth but it seems to have enough slack that it is hitting the top metal tensioner, I think. I just replaced the whole timing chain assembly last year and haven't even put 2 thousand mile on it!

The first time I took it off I noticed that one of the tensioners didn't appear to work. I fixed it and the chain was tight unlike before. Still didn't work.

Anyone know what could possibly be the problem?

[574-240sx]

I have the same problem and just changed out my timing chain and all the components 5000 miles age, and still have tensioner problems. The tensioner is so bad that, the braket on top broke because the slack was so bad. I think you just need a new tensioner. Nick

[Well Whoop De Do]

I checked all the tensioners and they seemed fine. The chain was tight. I though maybe thy were all off a bit. The links were on 7-7-9 spaces. I cahnged it so that the 9 links were on the left instead of the right. If I started it that way the pistons would hit. So the chain is on there fine!

Could a possible vacum leak or incorrect wire hookup cause the chain to rattle? I am at a loss to the problem hear. Everything looks good but it is not!

[zion]

I could be the chain guides...I belive that is what is wrong with mine. It does the same thing.

[Megaseth]

yeah, i think the guides might be out. the only problem is, the guides are no longer made. the new stuff has to be used with the new chain. thanks alot nissan

[Well Whoop De Do]

I figured it out guys! I let the cat idle and agfter a few minutes it was completely gone! Forever! I think there was some air bubbles in the tensioners and it took awhile to get rid of the slack.

Purs like a kitten!

[Aaron_RMS13]

I just changed my upper tensioner a couple of hours ago because there was a *slight* rattle.

After changing the tensioner it sounds like the chain is going to slap it's way through the valve cover. I mean, it is so loud that for a moment I thought the timing had jumped and the pistons were kissing the valves!

I drove it for about 6-7 miles and the noise hasn't changed a bit but after reading your post at least I can hope it will shut up.

Damn, it's frustrating to spend time working in the heat only to have the problem get worse.

The only good news is that so far no damage seems to have been done. If you turn up the radio and drive the engine feels the same as usual.

[SCOOTER240]

you might want to take off the hydraulic tensionere and check for a blockage-this port is extremely small and is easily clogged-an easy way to do this is to remove the tensioner and turn the cheankshaft with a ratchet or wrench-this will pump enough pressure through the oil pump to allow at least some oil to pass through the port-also if you are reusing an old tensioner or guides-don't-always use a new tensioner and guides-another thing to check is that the oil pump has been primed properly and that there is not a leak in the pickup

good luck!!!