Crank angle sensor (CAS) noise.....LOST!!!!!

[kpodj61240]

at idle my s13sr black top has this grinding noise (sounds like plastic). i used a stethoscope to see wear it was coming from and it sounds like right at the Crank Angle Sensor. It was taken out, and broken down. it looked perfect the bearing is fine too,so it got a good grease job and then put it back in and nothing changed. no decrease in noise or increase. it only seems to do it at idle 1100 rpm. if the rpms increase it goes away. did anyone have this problem and is it serious.

[boro drift]

Did you try running it with the cas cover removed?

[kpodj61240]

yea its still the same.

[boro drift]

Does your car run good, no abnormalities while driving?

[kpodj61240]

no it runs absolutely perfect. its just that noise bothers me and i dont want it to cause future problems because i sunk so much money in to that motor.

[boro drift]

I think your noise is coming from some where else and is resonating through the cas. I would try another cas though.

[kpodj61240]

i hope its not.....but u could be right. and i dont want to buy another cas and have it not be the prob. and i dont want to buy a used one...just cuz i dont want some one elses probs they may have had. but the valve cover was taken off. every thing looked fine. and nothing looked like it was being worn from like the time chain rubbing on somthing. im just lost...

[kpodj61240]

but like i said it only does it in spurts like it will be at idle fine and all of sudden rrrrrrrrrrrrrrrrrr then it will stop and do it like 20 seconds or 1 minute later. it really is kidof constant when my controller tells my fans to kick on or i pulling out in first gear.

[boro drift]

Yeah thats kind of weird. The only other thing I can think of, and this will sound stupid, I had a similar proplem, in a certain RPM range, it sounded like my timing chain was hitting metal. After three days with the valve cover off and inspecting, it turned out my alternator had come loose and the belt was slapping.

[kpodj61240]

well your not the first one to tell me it might be the alternator. but i cant see it being that because the noise is clearly coming from that area right were the cas is its really loud through the stethoscope at the metal portion of the cas. i mean u can hear it through the valve cover but it starts to fade

[boro drift]

Has the engine or cylinder head ever been apart?

[kpodj61240]

yes it has. there was alc rod and main bearings put in. arp head and main studs and a cometic head gasket. why what would that have to do with it.

[boro drift]

Just trying to rule things out. How does the gear on the cam look?

[kpodj61240]

i mean it has a little wear on the tip but thats expected. the engine supposably had 19000 on it

[boro drift]

On the tip of the tooth or on the side of the tooth twords the top?

[kpodj61240]

im pretty sure its on the tip

[boro drift]

If one of the gears has wear on the tips of the teeth, that will make noise because the gear mesh is too tight, which means the teeth on one gear are bottoming out between the teeth on the other gear. If that is indeed the case, something is whack with your cas, possibly a thrust issue with the shaft.