Ghettodeffender Posted March 7, 2012 Share Posted March 7, 2012 (edited) Hi guys, so my 280z is finally up and running pretty good, however it has a light knock. when i first got the car about a month ago i figured it was due to bad timing or the god awful old sludgy oil that was in the engine, well i adjusted the timing to factory settings, seafoamed the engine and changed the oil and the knock still remains. so i figured my valves could be out of adjustment, so i had a local shop adjust them and it turns out they were off spec, but still the knock persists. at this point unless i have a bent valve (which it doesnt sound like) i was thinking that perhaps my timing chain is rattling against something? i did notice when i changed my valve cover gasket that the chain wasnt completely tentioned extremely tight. so my question to you is could this perhaps be that my timing chain or tentioner is worn causing this sound? The car has 125,000 miles on it so if they timing set has never been changed it seems like it might be about that time to change it. I will be posting a video of the knock tommorrow Edited March 7, 2012 by Ghettodeffender Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 7, 2012 Share Posted March 7, 2012 Have you pulled or shorted spark leads one at a time and then in pairs to rule out the most common cause for "knock": rod and main bearings? A timing chain doesnt knock! Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted March 7, 2012 Share Posted March 7, 2012 And you're sure it's a knock not a rattle? Rattle from the valvetrain is normal. Quote Link to comment Share on other sites More sharing options...
Leon Posted March 7, 2012 Share Posted March 7, 2012 The chain tensioner is hydraulic, so the chain will have some play in it without the presence of oil pressure. Follow the procedure that Tony outlined, to make sure that the knock is not localized to one cylinder. Quote Link to comment Share on other sites More sharing options...
Ghettodeffender Posted March 7, 2012 Author Share Posted March 7, 2012 Ok so i pulled each plug and there is no change in the noise,i am positive i hear a rattle from the front of the engine where thetiming chain us located Quote Link to comment Share on other sites More sharing options...
Leon Posted March 7, 2012 Share Posted March 7, 2012 Use a stethoscope (i.e. a screwdriver with the soft end butted up to your ear and pointy end used to probe around) to find the locus of the noise. Quote Link to comment Share on other sites More sharing options...
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