travlnman Posted July 21, 2009 Share Posted July 21, 2009 Hello all, New to this forum, but not to Z's. I have just recently acquired a '78 280Z with the 5 speed. The car is all original, almost no rust, and the interior is in very good, just shy of excellent , shape. My previous Z cars had this issue, but not as bad. I have the dreaded injector tick, and it is loud ! At high revs, it sounds like spark knock. The plugs are a nice tan color and clean and also new. No indications of lean running anytime. I have checked the timing and it checks out at 10deg BTDC. Adjusting it has no effect. Naturally the injectors are the original 31yr old units. Are new injectors the only solution ? The engine has a rebuild in it's near future, hopefully with a stroker kit, but until then, do I have any options ? Thanks in advance for your help. Nice forum by the way, much more activity than the other Z forums I lurk around. Quote Link to comment Share on other sites More sharing options...
big-phil Posted July 21, 2009 Share Posted July 21, 2009 try adjusting your valves. Could be them?? unless your positive its the injectors. Quote Link to comment Share on other sites More sharing options...
travlnman Posted July 21, 2009 Author Share Posted July 21, 2009 Crap, left that out, sorry. I adjusted the valves the first week , hot, .010" intake, .012" exhaust. Same day I flushed out the possibly 31 year old brake fluid ( yuck! ) That crap was as black as the tires. I used an automotive stethescope to try to pinpoint it, and it seems to be the injectors, as sure as I can be anyway. Anybody got any cold valve lash numbers ? I could check it both ways. Quote Link to comment Share on other sites More sharing options...
travlnman Posted July 21, 2009 Author Share Posted July 21, 2009 I've done so much, I tend to forget. Also in addition to new plugs, I have new wires , cap, rotor, and coil. All of which made it run smoother, but no change on the noise. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 21, 2009 Share Posted July 21, 2009 According to my trusty FSM: Valve Clearance mm (in) Hot Intake .25 (.010) Exhaust .30 (.012) Cold Intake .17 (.007) Exhaust .24 (.009) Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted July 21, 2009 Share Posted July 21, 2009 you'd be surprised how loud those injectors can be, even when they're running fine. Mine are all pretty loud even though they're all new. Nothing wrong with them, but all 6 of those batch firing make quite a bit of noise. Quote Link to comment Share on other sites More sharing options...
Oddmanout84 Posted July 21, 2009 Share Posted July 21, 2009 Yeah, I remember the first time my uncle heard the car run... He thought the injector click was a valve clearance issue. So did I at first, those things are LOUD. Quote Link to comment Share on other sites More sharing options...
travlnman Posted July 21, 2009 Author Share Posted July 21, 2009 That's cool. Thanks for the cold lash numbers, I may double check it to be sure. It seems that some are just louder than others. I had another '78 years ago, not quite so loud, then I had a '79 that was pretty quiet. Seems the ZX's may be a little more quiet than the Z's. Some good info, here, most of the other forums are dead,or full of teenagers street racing and putting on wings and such. Cool if that's your thing, but it's not mine. Thanks again. Quote Link to comment Share on other sites More sharing options...
z-ya Posted July 21, 2009 Share Posted July 21, 2009 Usually you can't hear the injectors, except on hydraulic heads (no valvetrain noise). I would try pulling the injector connectors one at a time while the engine is running to see if one injector is louder than the rest (or that they all sound about the same). Quote Link to comment Share on other sites More sharing options...
travlnman Posted July 21, 2009 Author Share Posted July 21, 2009 Yet another good idea.Thanks Quote Link to comment Share on other sites More sharing options...
thetremendoustim Posted July 21, 2009 Share Posted July 21, 2009 are the injectors supposed to all tick loudly? My L is only running on like 3 cylinders right now and my plugs are always coming out really wet and black, not to mention the exhaust smells like a lawnmower just went by, should all the injectors have the same loudness of tick? I mean, some are LOUD and other are pretty soft, you have to put the screwdriver up to them to hear them. Quote Link to comment Share on other sites More sharing options...
travlnman Posted July 22, 2009 Author Share Posted July 22, 2009 One would think they would be nearly equal, but who's to say. I tell you what has helped. There will be naysayers, doubters, I was skeptical, but after my wife said, it's quieter, what did you do..... The proper dose of marvel mystery oil in the tank. I know, I know, I'm not a wonder in the can type either, but it was suggested, and it has helped. may come back with a vengence when I run a tank without it, but halfway into this one, and it is better. So much so , that I now believe I hear a hint of detonation when I rev it up(believe that was mentioned out of the gate, sorry) . I will try pulling back the timing a little tomorrow, and see what's up. Maybe it's just a twist of fate that they got quieter now, who knows. Time will be the ultimate judge here. Quote Link to comment Share on other sites More sharing options...
ddog437 Posted July 25, 2009 Share Posted July 25, 2009 Have you checked for any exhaust leaks are the seal of the manifold? This can lead to a very loud ticking noise that I have encountered, sounds more harsh then a typical exhaust leak. Quote Link to comment Share on other sites More sharing options...
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