Ticking Noise After High Rpm At Full Throttle

[sonicii]

I have a weird ticking/knocking noise that has developed in my car, but only occurs for a few seconds after heavy acceleration and high RPM. it then disappears.

Only noticed this the other day when accelerating hard in 2nd gear to 100km/h. it hit the rev limiter, after that I shifted straight to 5th and then to 6th, but then had a metallic sounding ticking sound under light acceleration, it did not occur when decellerating. Everything performed normal, no loss of power, no vibrations or roughness, just the noise.

After about 10 seconds, the noise stopped completly.

The only way I could get it to occur again was to do another hard acceleration into high RPM.

My initial thoughts were an exhaust manifold gasket, as the sound seemed to be about regular enough for a leak on just one cylinder, and changed with engine RPM (not vehicle speed).

I have driven about 50km since then (city driving) and haven't had any other issues at all.

I took it for another hard drive yesterday afternoon to have another listen to the noise and managed to get it to occur once, even with several attempts. But I am thinking the noise isn't quite metallic enough for an exhaust leak, and am now starting to wonder if it is a clutch/DMF problem. as I couldn't really hear the sound from outside the car (driving next to a concrete barrier).

I have been a bit sus of my clutch since I purchased the car, the 'take up' point seems to change at times, and if the clutch gets hot, the pedal doesn't return all the way up. I have also noticed if I press lightly on the clutch pedal while accelerating, I can feel and hear a vibration/knocking sound, this occurs all the time, and has done this since I have had the car.

Just after any thoughts/ideas..

[tranman]

I know that my clutch is quite 'rumbly' when not engaged e.g. car idling in the drive-way in neutral. I suspect a worn thrust bearing. Perhaps you have something like that?

Just an idea which I'd throw out there, seeing as though you've come up against some clutch niggles.

[scotty nm35]

Collapsed cat perhaps?

Sounds like your clutch fluid needs changing too, or at least a bleed...

[Magic]

Where does it sound like it's coming from?

[sonicii]

It seems to be coming from behind the driver side footwell area.

I've never had a collapsed cat, but I would assume that would be more of a random rattling noise, this sound is much more regular and in time with engine RPM?

Clutch probably does need a flush with new fluid. It is the one fluid I haven't changed since purchasing the car.

Thanks.

[Magic]

It's hard to tell without hearing a video of it. Even still it could be a few things. I'd start with checking the exhaust heat shield - that's caused the acceleration rattle for me in the past. You can just cut that off. It's also worth checking your oil levels though as that can happen when you're getting the common oil burning issue, which also contributed to a 'marbles in can' rattle on my old engine.

[sonicii]

Thanks. Oil level is fine. I think the noise was a bit different to heat shield. Also couldn't really hear it from outside the car ( driving next to a concrete barrier). And it was a fairly repetitive/regular noise that changed with engine rpm.

I took it for a bit of a drive again today and couldn't get it to happen again.

Still a bit perplexed with it. Will try to Capture a video if it occurs again.

[sonicii]

After all this time, this noise has started again, however, it now seems to happen under light throttle once the engine is fully warmed up, and only occasionally.

I have found if I put some pressure on the clutch pedal (not enough to disengage it), the noise stops, so I think that is a fairly reasonable indicator that it is a clutch problem.

The other weird thing is it seems to be louder if I am making a hard right turn while accelerating, which made me think 'engine mounts' for a while, but they appear all ok.

Looking around now for a replacement DMF and clutch. I don't want to go with a single mass fly as this is my daily and I spend a lot of time under 2k RPM, and many with SMF say that it is quite noisy under 2K.

[ChrisB]

Timing Chains?

Mine would rattle (ticking noise) about 2500 rpm on the VQ25DET but Scotty fixed that.

I have heard VQ35's with noisy timing chains.

[sonicii]

I don't think it is the timing chain. It only occurs intermittently and only when accelerating. I also wouldn't expect timing chain noise to go away when I put pressure on the clutch pedal.

It is also silent at idle, where timing chain noise is usually most noticeable.

[V35A]

Sounds like my car when i first purchased i,t clutch was burnt out i could hear metal flying about and the clutch pedal would get stuck as well. Yeah sounds about right 2.5k-3k to change your clutch

[sonicii]

Thanks.

Looks like just under $1k for a LuK DMF (OEM) and an exedy clutch kit (clutch plate, pressure plate and throwout bearing). I should be able to do the work myself, which should save quite a bit in labour. And a good excuse to buy myself a transmission jack.

Does anyone know if it is worth doing the rear main seal on the engine or the transmission input seals while the transmission is out? or do these not give much trouble?

[scotty nm35]

If you do the rear main without dropping the sump you will find out the hard way, it's not a good idea... Then once the job is done and you have a weeping seal, you will need to rip the engine out and gearbox off again to fix it properly.

As always, don't change what isn't stuffed.

[sonicii]

Excellent.. thanks for the info!

[sonicii]

Well, I have placed an order for a new LuK DMF and Exedy clutch kit. Should be here in a couple of weeks, then I will have to arrange a time to fit it. Will post the results back here.

[sonicii]

Well, fitted a new LuK DMF and Exedy clutch kit today, seems a bit easier to control now, the clutch isn't as 'bitey' as the old one. But I really haven't taken it for a long drive yet. The existing clutch seemed to be factory, as all components had LuK and NISSAN written on them. There was still plenty of 'meat' left on the clutch plate, but the DMF seemed to have a bit of play. There was also a few 'shiny' spots on both the flywheel and pressure plate, but didn't have any signs of chatter, not sure what the shiny spots mean??

The Exedy clutch feels a bit heavier than the factory clutch and makes the clutch pedal feel a bit 'spungy'. I am thinking a braded clutch line may help with that?

Does anyone know if there is a difference between the LHD and RHD braded clutch lines?