KA24DE Timing chain noise... but at ONLY 2000-2500 RPM?

[ZiG]

Just a quick question, any of you 240sx KADE guys have a ticking from the timing chain that comes at about 2k and leaves at about 2.5k?

At idle the engine sounds pretty much perfect. At cruising speed (say 3000 RPM) it also sounds mint. But right in that narrow RPM range, I hear what I would call a buzzing from the engine. When I stick my head under the hood and rev it up it definitely sounds like it's coming from the front of the engine.

For reference I've removed both upper guides some time ago (it was making a bit of noise, and removing the guides and cleaning the tensioner temporarily solved it. which was about 10k miles ago?)

So yeah, pretty sure it's the chain, but the fact that it doesnt make noise at idle sort of confuses me. Any thoughts?

I just need it to last me the rest of the semester and then the 500 mile drive home, and then it's getting ripped out and rebuilt...
Modified by ZiG at 10:07 PM 3/24/2009

[dwaynedman]

What you are probably hearing is lifter noise !! The solid lifters in these motors are deffinately noisy. I have adjusted my valves several times through engine overhauls, and it almost seems impossible to get rid of all valvetrain associated noise. Just a possibility, but the lower chain guide was also part of a Factory Service bulletin for breakage if I am not mistaken. Somone correct me if I am wrong, but I believe that the new factory chain guides are updated, and designed differently.

Later,D