PhilbertZ Posted July 29, 2008 Share Posted July 29, 2008 Hi guys - pushing the n00b envelope even further with these 2 questions. I've done a valve adjustment twice now on my 1980 NA 280ZX - runs great...but I've noticed some noises that I can't figure out with the engine. Noise #1: Exactly at 3800 RPM - either revving up or revving down - I hear this rattling noise coming from the engine. It sounds like a heat shield is loose and rattling but i've checked many times and all those are mounted tight in the engine bay - can't find anything loose in the bay at all. Doesn't affect performance at all - it's just a metallic rattling sound that happens every time I cross 3800 RPM. Noise #2: At idle and with throttle, there is a "ticking" coming from the engine. At first I thought it was the valve lash since I had adjusted the valves (twice) recently. However, when I listen close and put my hand to the valve cover and other components, I notice that the valve cover DOES NOT seem to be the source - it instead seems to eminate from the injectors/fuel rail (circled in image below - not my car - just an image I found online to indicate the metal tubing I'm talking about): Should I be worried about these noises? What are the sources of these 2 noises? It's driving me nuts not knowing... Thanks in advance Quote Link to comment Share on other sites More sharing options...
Noddle Posted July 29, 2008 Share Posted July 29, 2008 The rattle may be like mine, the insides off the muffler is rusting away and bits rattle around. The ticking may be the injectors turning on/off quickly Nigel Quote Link to comment Share on other sites More sharing options...
woldson Posted July 29, 2008 Share Posted July 29, 2008 Yep, at least mine tick away quite nicely. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted July 29, 2008 Share Posted July 29, 2008 on my 78, i found a heatshield was the culprit of the nasty rattle. my fix was bending it enough so it wouldn't resonate anymore. the ticking could just be the noisy injectors Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 29, 2008 Author Share Posted July 29, 2008 Thanks guys. Are noisy injectors BAD or just...noisy? the ticking sounds like it's paced normally with the RPMs - does not get worse really... Can they be remedied with anything like an additive or is that all bunk? I'll look more into the 2800 RPM rattle source - thanks for the tips! Quote Link to comment Share on other sites More sharing options...
woldson Posted July 29, 2008 Share Posted July 29, 2008 BigPhil found some that are really quiet. It is normal. Just out of curiosty, do you still have the mechanical fan? Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 29, 2008 Author Share Posted July 29, 2008 BigPhil found some that are really quiet. It is normal. Just out of curiosty, do you still have the mechanical fan? I believe the mechanical (belt-driven by the motor) fan is what I have. Previous owner was original owner and kept everything stock to myn knowledge. I've seen the "electric fan" mentioned several times here as an aftermarket upgrade...what are the benefits/drawbacks of converting to electric? Quote Link to comment Share on other sites More sharing options...
woldson Posted July 29, 2008 Share Posted July 29, 2008 No just that is about the nosiest part in that engine bay!! Personally, big difference in stock situation. BEWARE of over heat of a/c if using one. Search on this issue there is a lot of info. Quote Link to comment Share on other sites More sharing options...
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