I think it is related to the adjustable Camshaft timing, It is a vibration that became really pronounced when I fitted a new lightweight lower pulley, which is why I replaced with the original heavy one which made it a lot less noticable. The engine has been extensively refurbished, and it has made no difference. Thoughts are... Maybe one solenoid to the oil pressure system is faulty? how do you test for this ? or All of them do it. ???????? its maybe just a quirky thing, I avoid hanging around that rev range for long. :unsure:
Me too. I am not sure if I had it to begin with, when I installed the UD pulley, but I picked up on it not long after it was installed, It only seems to last for a few seconds as you power though 4,000rpm, I can't actually feel it, but I can hear it. But I don't see how a UD pulley can cause a new noise to appear from what seems to be the valve train. Maybe it's just lack of oil or some thing. I was thinking of running a bottle of oil system cleaner next change.. What do people think of those products? It tried unplugging the VTC plugs, made no difference. And I can't return the car to the stock pulley, as I broke the lip on it when I pulled it off . I had a feeling from the start when I first noticed the noise that it might be from the UD pulley. I get a similar sound if not the same, when I start the car in the morning, when it has a high cold start IDLE like, 1500 for the first 5 seconds I will get this rattle sound, doesn't sound like its from the block, but more of a valve train noise. I though it was a lifter. But lifters are meant to tick? So maybe I have bad oil flow. It doesn't happen all the time when I start it though. I don't know if it was me, but I seemed to feel a reduction in power only when it makes that noise, as you power past 4,000rpm, but when it stops it feels normal.
Me too but I get the noise at 2800 rpm I don't think mine is in the engine though. I think it is a vibration in my exhaust system. Perhaps one of the heat shields is either loose or just touching somewhere it shouldn't which sets of this particular harmonic. Cliff
A lifter noise sounds something more like 'dock dock dock dock dock' thats when its really bad and goes faster/slower depending on rpm. I think i know the noise you guys are refering to. At about 4000rpm i get this bzzzzzzzzzzzzzz noise yes almost sounds like its apart of the exhaust note, couldnt figure out what the hell it is, even thought it might be detonation as i never heard detonation before. But it sounds like u/d pulley is the common denominator, at any other rev range you wont hear a problem at all.:thumbsdown: Ps. Are your underdrive pulleys perfect and balanced? mine would have a couple of little dings on it etc.. i'd like to balance it next time its convinient, the question is why does it only vibrate at 4000rpm?
i had a noise problem like this bzzzzz sometime ago it turned out to be a loose ring gear on the drive plate. nissan is already welded so unlikely to be the cause.can you pin point the precise source?
Re: A lifter noise sounds... I guess then its more of a dock sound lol.. Its definitely not a TICK. As for my UD pulley, visually it was/still is? perfect when I fitted it. Whilst revving high in neutral looking at the pulley, it seems to be rotating smoothly as well.
Installing the under drive pulley Didnt cause it. It was there before. Thatrs why the original pulley was called a HARMONIC BALANCER. It's intent was to damp out those sorts of resonances. It is pissin me of so bad I am going to put the normal pulley back on. I can hardly notice the power increase of the pulley but I can sure feel the rougher idle I have now.
what make ud is it, always pays to getem chequed, before installing. if you had slight engine ballance probs, before the install, the pully could cause this to become a little more pronounced.
Yep Happened as soon as I installed the UD pulley on my engine. It is not a harmonic balancer, so it is not dampening out a noise that you would already be hearing were the OEM item not a Harmonic Balancer. Just get a louderr drone on your exhaust and you will not hear it as often Bugs the crap out of me more from a 'my car is making embarassing noises' perspective :LOL: Cheers Rob
I reakon you should put some engine flush in before next oil change then run a thicker oil something along the lines of 20-50 or 15-50 synthetic can't remember run a search, if its a faint 'dock' it will probably go away. Otherwise try some lifter free as well. Then next oil change just run the thick synthetic oil without any additives and see if the noise comes back.
Mine came from J4play When I was talking to him he told me it had been balanced and is spot on. I belive him 100%!! This is why the factory pulley is what it is. 5kw isnt worth the extra vibration harshness, and possible engine damage. I will change back.
Only noticed when I installed the U/D pulley Now have the original pulley back on and the noise is greatly reduced. I rarely hang around at those revs anyway, it's either over 5 or under 3000 rpm most of the time, just the way the auto is. I sold my U/D pulley. Interesting to hear your thoughts guys. Cheers:zlove:
I am gonna do the same Did you keep the cardboard things off the belts?? I forgot what sizes I needed again to go back to the old pulley. I need to buy new belts.
