let's play guess that noise!

[EstoMax]

hey all,

A couple of months ago i started hearing this strange noise at low revs and periodically at idle. It was especially annoying upon turning off the car. It has gotten louder since then and now is definately noticable at certain rpms.

it sounds like my exhaust is hitting something as it goes with the engine speed and sounds like metal clattering around. I cannot for the life of me figure out where it is coming from though. I know it is definately louder on the exhaust side and towards the back of the engine. I looked under the car and shook everything i saw, but nothing seems to want to clatter like that.

Sooo i took some videos and will share them here:Here is the vid of the engine, it is not as easy to hear it here because my valvetrain is quite noisy.http://www.youtube.com/watch?v=5esWfqKwa5cAnd here it is when i turn off the engine.. that's the most embarrasing part.http://www.youtube.com/watch?v=Y_eXf0VE1KM

I can also hear it pretty consistently if I'm coasting in a high gear around 1500+- rpm

I am starting to think it's my bottom end, but i checked my compression and its damn good at 165 158 160 165. I took off my valve cover as well and cams and valve caps look ok.. nothing loose there. the engine has about 23k miles on it, the valve train has been this noisy since day 1

Cheers for input!MarkoWiseco 9:1, Pauter rods, s13 cams
Modified by EstoMax at 9:21 PM 10/28/2009

[KFL]

sounds like a exhaust leak somewhere possibly manifold/dp/exhaust. If you have wrap covering anything might be a good idea to remove to inspect.

Thats sounds pretty loud overall what oil are you using, may want to get a little thicker to quiet it down.

[EstoMax]

i'm using 20w50 amsoil synthetic :P

i think i need to really tighten my valve lash up... but my machinist also told me that he built the motor 'loose' because my hp goals were quite ambitious.

One other detail i noticed test driving it today is that the noise goes away if i am at anything above 15 inches of vacuum. It only does it at idle sporadically and then consistently when i'm in full vacuum in gear. I can hear it up to 2000 rpm when i get off the gas. once i give any throttle it goes away.

i pulled spark plug wires one by one to check for rod bearing (which i have had before and sounds different) and it does not change so that rules that out.

cheers for more input!Marko

[Chris28]

It kind of smells like rod knock, but it's not loud enough. Adjust your valves and see what happens.

I usually play the "guess that smell" game haha.

[Turbo24sxt]

sounds like rod knock to me... it might have just spun hence why it is not as loud as it usually is, however stop starting it and reving it, drain the oil let it sit in the pan for a few minutes after it is drained out of pan,

then pour it into another pan slowly ... and towards the end if there is any metal in the bottom, its most likely rod knock ...

i recently just spun mine and caught it before it ruined anything major but it was very similar sounding to your video, and wasnt very loud because I shut her down quickly....

have you been bouncing it off the rev limiter lately?
Modified by Turbo24sxt at 10:49 PM 10/29/2009