Ok, so just recently i have been hearing a noise coming from my engine that sounds like a heatshield is loose, but i dont have any heatshields...the sound of a loose bolt or stuff rattling in a can comes to mind. The sound seems to be the loudest when i listen for it near the valve cover

The noise happens at part throttle, and sometimes when i back off the gas. But *sometimes* i can hear it at idle...doesnt seem to do it when i give it full throttle though, even at low rpm's

The o2 sensor has been replaced, and the plugs look fine with no signs of detonation. A/F gauge reads rich and retarding the timing all the way does not solve the problem

I am thinking/hoping it may need a valve adjustment, but for some reason i think it is more expensive than that

The turbo spins very smoothly..at first i thought it could be the blades hitting the housing....there is a bit of shaft play

Could a bad rod bearing be the problem here?

the setup is - '00 b18b, 60-1 turbonetics, 450's and the uberteg chip, motor has less than 30k miles, with 6-7k boosted


TIA, any advice will be greatly appreciated

 

Marbles in a can is usually detonation. But if you hear it at idle, it could be your valves. Adjust em and see if it goes away. Ticking is the best way to describe if they need to be adjusted. put a rachet or screwdriver on the valve cover and put it up to your ear.

 

Its not really a ticking sound...more of an annoying rattle, just like a heatshield sounds when its bolts are loose

any other ideas?

 

does your car feel weaker? if your plugs are good i guess your ok and all the stuff you did to prevent detonation and it still makes the noise? If thats it try new plugs and gap them at .030

 

no, the car does not feel noticeably weaker...new plugs are in, but they are gapped at stock spec

Im HOPING there is no mechanical problem with the motor...id like for it to be in the tuning but its hard to figure out as the motor only recently started to make this noise

What are the signs of worn/bad main bearings?