Hello. Trying to track down the cure for a rattle type of noise that tends to be when cold and low revs. Cambelt, pulleys done 2 years ago at Eurospec. When I first heard the noise, I thought it was a small exhaust blow but it's not that. Eurospec have stripped the front and had another good look at pulleys, timing belt, tensioners etc and they're fine. They suspect the VVT solenoids or gears.

A bit of research leads to this https://z32.wikispaces.com/Variable+Timing+Control#Function-ECU Control-Non-Turbo which seems to point to the gears (if it happens when cold, the solenoids wouldn't need to operate anyway).

Has anyone had this issue and if so, what was the cure?

Sounds like a small bag of spanners but runs smooth and gets quieter when warm and running at motorway speeds - no horrid noise at all.

 

Cheers (and yes I've come back because I've got an issue with my Zed. At least I've still got a Zed :) )

Good to hear from you Mike and hope someone can help you out mate.

Have the vvt springs in the cam housing at the front been changed after the strip down, was the cause of my rattle initially

@ Gaz_300 thanks mate

@ groover thanks also - no, haven't changed the springs but they are mentioned in that link I posted.

Been swopping emails with "incredibly helpful Nick" at ConceptZ and getting more suspicious about the gears.

Just got the full version of ConZult (Hi Eric) because that has a solenoid on/off test and will see what transpires in the am.

Still interested in hearing other experiences of same thing. "Knowledge is power".

Cheers all :)

What is the tickover speed when it makes the noise?

 

Jeff

It's there without any throttle so 1,000 - 1,200 on immediate cold start, and remains when down to warm tickover say 800rpm. Haven't looked for the upper limit yet.

(PS Hi Jeff)

Any chance it's the valve lifters?

Hi Gio, long time eh? ok I know you mention belt was done etc. but this sounds more like belt shudder to me, very rare to find vvt as bad as you mention. Has the engine been run with the covers off? Would not be surprised if the belt was flapping on the run from the adjuster to the first cam. I would investigate the tensioner not controlling the belt tension correctly, either because it's failing or more likely the set position is too small so is bottoming out and chattering the belt and passing that on to the vvt pulleys.

 

Good luck

 

Jeff

@ dutchgold92 - pretty sure Eurospec would have spotted that, doesn't sound like it to me.

@ Jeff - thanks will pass that on.

Listen to the noise when the guy revs the engine, it's a more subtle spring rattle sound, the harsher sound is massive belt slap as mentioned before, maybe even a bad belt runner. Does the spring noise sound like yours?

 

 

Jeff

It's similar, here's mine

 

Mike

It's similar, here's mine

 

Mike

 

Ok Mike that is nailed it, that is not the vvt noise it is the belt is slapping due to one of the reasons above, hang on I feel a picture thread coming on back in 5 >

 

Jeff

Edited March 31, 20178 yr by JeffTT

Ok I am back, so the most likely cause of the belt slap and subsequent vvt noise is an incorrectly tensioned cambelt, now this can be made worse by a noisy pulley but in 99% of cases the root cause will be the tensioner.

 

So what goes wrong and how come it goes quiet after a while, so see the first picture below of a tensioner closed up fully, I came across this many times when changing a zed cambelt. This is usually due to been incorrectly fitted by a mech or owner who has not understood the set up procedure when replacing the belt, I will add I did one that had come from Nissan main dealer like this so dont think back street garages are the only one` to get it wrong.

 

 

There is an amount of preset that is required, the reason been is the belt is a moving part and grows with acceleration and temperature albeit a small amount. The belts have a significant inbuilt stretch specification, the first and most important one is when a new belt is fitted and run up for the first time, this is manufactured in and will set the rate at which the belt performs over its lifetime, this is why you should NEVER reuse a cambelt once it has been removed even if it is low mileage, that initial stretch parameter is done and will not return.

 

 

So looking at pic two the tensioner has been set with a gap just less than specified by the Nissan ( come back to that later ), this allows the adjuster to be a free floating tensioner that can not only extend out when accelerating the engine speed or as temperature of the belt rises, but just as important is when the belt is cold it has room to move in and lessen the tension accordingly but be ready to extend out as required.

 

 

 

So now we know how it works it all starts to make sense if the tensioner is set in the fully closed position when fitting the belt it can not retract when it needs to and no longer is a floating tensioner but a solid adjuster with no give, this lack of give causes the belt to slap and the vvt cams to shudder and hence produce the noise from both the vvt pulleys and the louder noise from the belt itself.

 

Remember I mentioned the adjuster in pic two was set below the setting recommended by Nissan? yes well that is because as you rotate the engine for the first time with a new belt on, the belt settles and the adjuster moves out to the correct position, if you set it as Nissan suggest from the start the settle position leaves the tensioner open to much.

 

Of course a seized tensioner can have the same noise for the same reason even though it looks to be extended out from the set position, for this reason the belt MUST be removed to check.

 

Finally, why does it go away when the engine gets warm? easy the belt grows a little when its warm and gives a little slack back to the tensioner, that is a sure sign of a tensioner set incorrectly as a seized one will still not move.

 

 

Hope that helps Gio

 

 

Jeff

Edited March 31, 20178 yr by JeffTT

Thanks Jeff. Just to clarify, can this be corrected without taking the belt off? Or if it needs taking off, you say it needs new belt because you mustn't re-use belts?

Cheers

Thanks Jeff. Just to clarify, can this be corrected without taking the belt off? Or if it needs taking off, you say it needs new belt because you mustn't re-use belts?

Cheers

 

Sorry was writing and re - editing that post, should give you the answer`s you need now, at least its an easy fix.

 

Jeff

Sorry was writing and re - editing that post, should give you the answer`s you need now, at least its an easy fix.

 

Jeff

I prob leapt in too quick :oops: so belt must be removed and therefore changed?

Gio

I prob leapt in too quick :oops: so belt must be removed and therefore changed?

Gio

 

Yup ! check the water pump and thermostat again whilst your in there as well as the belt runners.

 

Jeff

Edited March 31, 20178 yr by JeffTT

[ATTACH=CONFIG]105321[/ATTACH]

 

Ha ha, love that !

 

Jeff

Bullet dodged, thanks to Jeff. Which is kinda fitting since he did the UK thing on this Zed a few years back. (And looked after my other 2 Zeds.)

(Also thanks to Lymon for the ConZult and Eurospec for fitting in the inspection so quick.)

Floppy belt as suggested by Jeff. Possible failed hydraulic tensioner. Parts ordered from ConceptZ. And I'm back home giving thanks no disaster when we went to IoW last week or last month ferrying sick kittys about.

Oh, and here's the Zed back in 2011 freshly prepped for UK registration.

Bullet dodged, thanks to Jeff. Which is kinda fitting since he did the UK thing on this Zed a few years back.

 

Floppy belt as suggested by Jeff. Possible failed hydraulic tensioner

 

and they all loved happily ever after ...lol

 

Glad to of helped, even remotely !

 

Jeff

Second drive today after timing belt service (and exhaust work) and my car developed an actual exhaust leak on the way home. Needless to say, after reading this thread I was very paranoid :lol:

Second drive today after timing belt service (and exhaust work) and my car developed an actual exhaust leak on the way home. Needless to say, after reading this thread I was very paranoid :lol:

Just because you're paranoid doesn't mean they're not out to get you :detective:

Did you retain the original tensioner during the belt change?

Did you retain the original tensioner during the belt change?

No. It had a normal belt change by JeffTT on import May 2011 (precautionary because that way, you _know_ a timing belt change has been done). Then after 90,000km in May 2015 (I'd done a lot of miles) Eurospec did the "2nd time around" which included pulleys and the tensioner as it should. So either it has failed, or wasn't adjusted to spec or something else.

Just one of those things that Zed ownership throws at you. At least it was caught in time so I'm relieved more than anything else.

That's a bit annoying. Oh well at least it's in hand now, might be worth talking to them. You might get a bit off if the part/labour is defective.