weird motor knock and modified pcv routing:VIDEO:

[DaytonaBlues]

i have a 99 Z28 ss clone. 119k miles, motor is all stock never been apart (stock except for a lid, FTRA and SLP cat back). the problem is i have a real loud clacking sound only from 1300 to 1800 rpm. in the video at around 1:06 you can REALLY hear the clacking sound. the motor is being held at around 1800 revs. I got no idea what the noise is but i can say it doesnt do it when the engine is cold, or when you go past 2 grand. motor does make a lot of valvetrain noise but it idles well and still pulls hard to 6000. It MAY have had a Predator hand held tune done but i dont know how to tell. I have a scan tool too but i dont know what the stock LS1 timing should be at idle, WOT etc..

secondly, take a look at the PCV setup since i ripped out the old worn stock PCV valve boot and added a catch can (cheap can but better than without) along with the newer orifice style pcv valve. i dont know if theres a better way to route the pcv hoses and the valve as you see at the end of the video. (only 2 minutes long). the way i have it now is 3/8" hose from intake to the pcv valve end, then the valve sits in a sparkplug boot(so i can turn the pcv valve vertical like some suggested). from the sparkplug boot/pcv another hose to the catch can. the stock pcv hoses are still on the motor.

[SMWS6TA]

almost sounds like an exhaust leak.

I can't hear any metal ticking....

[DaytonaBlues]

almost sounds like an exhaust leak.

I can't hear any metal ticking....

at 1:05 or so into that video it sounds like my rockers are whacking against the valve cover (drivers side)...im glad you dont hear nothing bad. there is a bad valve clatter sound at 1800 rpm. bad enough you can hear with the windows up and over the drone of a Loud mouth exhaust..stationary holding the rpms at around 1800 its LOUD. i gotta drive this thing cross country too.