Not my clutch again ?!"£$

[Tom_S14]

Hope you guys aren't as bored of this one as I am http://300zx.co.uk/200sx/ubb/frown.gif

Mr Nissan put a new release bearing on last week. All lovely, no noises... today... It is back http://300zx.co.uk/200sx/ubb/frown.gif

1) they're not replacing the bearing, but just slapping a load of grease on it.

2) could it be pitting or wear on the shaft itself ?

Must be the clutch release mechanism somehow, can't be the gearbox, becuase it makes the noise, in gear, clutch down. Car doesn't move, input shaft to gearbox can't be moving, hence can't be gearbox.
Doesn't make any noise under load.

I'm pulling my hair out (what's left of it) on this one. It doesn't make sense.
Does anyone have a magic wand ?
Tom

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1996 Blue/Green S14 (manual)
K&N cone filter
2.5" Tube-torque Cat Back Exhaust.
TechTom MDM-100
Race-Technology AP-22
http://tom.marshall.tripod.com

[goosegog]

They / you should try a little grease on the tip of the input shaft as it sits in the spigot bearing. I greased mine and it stopped this odd noise

You may wish to try spray grease
Wurth make some called HS2000
You could spray this in without removing anything

Good luck

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[Tom_S14]

goosegog,
Cheers, when you say spigot bearing... ? is this the release bearing or a different one ? I've got an exploded diagram here, and I can only see the release and box input bearing.

Tom

[geoff_s14]

Tom,

Sometimes you can never cure this noise. My current car has suffered from noisy release bearing from new. Nissan has fitted three replacements so far, the current one is quieter than the previous ones but not completely silent. The release bearing was redesigned a few years ago in an attempt to cure the problem, but it didn't work. In my case the bearing I have now is the older design, and like I say the quietest.

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Geoff
Emerald S14a

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

[Tom_S14]

Geoff,
I remember you telling me about this at Donnington now. Baffles me why they can't design a release bearing... there must be some strange reason.
What's wierd is, with the clutch down, it's grinding away making that awful noise, but if you rev the engine it doesn't seem to change much. Really odd.... How loud is the noise yours makes ? People can hear mine from across the car park ! (quite a big carpark http://300zx.co.uk/200sx/ubb/smile.gif )

Tom

[geoff_s14]

Tom,

The noise mine makes is was a graunching noise on the overun when decelerating in gear between 3000 and 2500 revs. It used to be so loud as to attract attention from pedestrians, but now with the current bearing, the noise is more like a low pitched whining which subsides considerably after the first 5 minutes or so of driving. The car went back to Nissan UK in Sunderland for them to look at, but they admitted they couldn't completely cure the problem, and the brand new 200 they loaned me while they had mine was just as bad.

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Geoff
Emerald S14a

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

[The Gill]

If they are going to grease the release bearing they should use a low melting point grease (so I was informed when I had similar problems).

[Tom_S14]

Hmm, they are definitely greasing it, but maybe they are using the wrong stuff, and it's coming off or not working effectively.
The first release bearing they replaced was silent for 3 days, and the 2nd one lasted a week. Interestingly, since the last time they looked at it, the engine turns over much faster on the starter !!! Making me wonder if it could be an alignment problem due to a poor bell housing casting or something, I think someone mentioned this last time I brought this up.
Bit odd really, does the 300zx have the same problem, S13 ? Sounds like it's a really common problem.
If I go to a bearing manufacturer and get one of the same dimensions ? I wonder if it's because the bearing is weak due to a large internal diameter and the dimensions of the release fork or something ?

Tom

[goosegog]

Tom, my presonal view is that it may not be the realease bearing but instead the spigot bearing where the input shaft lays in the back of the crank in the centre of the flywheel or perhaps dry splines in the centre plate
The release bearing is of a Donkey's years old design and is apparantly even the same part number as that required for the Datsun 510, 810 etc

http://www.ratdat.com/mycars/tdl835k.jpg
A nice 510 Bluebird courtesy of www.ratdat.com (http://www.ratdat.com)

I don't believe such an old design could become a problem just because it's on a different car. Mine howled so I greased both spigot and splines and all is still well!

Ferg

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[Tom_S14]

Goosegog,
Ah, that's where the spigot bearing is. I only had a diagram from the service manual to go on, and it's not very clear.
You said I can grease the spigot bearing with out taking anything off ? You mean through the fork hole ?

Tom

[geoff_s14]

When my car came back from Nissan, they also faxed a report to my dealer with their diagnosis. Although they specified for some reason that it was a report for the engineer, and not the customer, by friendly service manager read it to me but wouldn't give me a copy. I can't think why they were so cloak and dagger, but anyway, from what I can remember, the gist of their report was that the release bearing assembly incorperated springs (or was it shims?) for the purpose of damping resonant vibrations from the engine to isolate them from the transmission, and that it was this spring/ shim which was itself resonating and causing the noise and vibration. I haven't seen an exploded diagram of the clutch components so don't precisely know what they mean. I don't think they were referring to the springs on the clutch plate itself, which serve the same function.

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Geoff
Emerald S14a

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

[goosegog]

Tom, I haven't tried greasing the spigot bearing through the fork hole as I had to take mine apart to renew the clutch.

Come to think of it, you'd never get the grease in there past the centre plate
It's a doddle to remove the gearbox if it's been out before and the tech who fitted it greased the bell housing bolts upon reassembly.

Geoff, the release bearing is quite a free floating affair and mounts to the fork in dimples and is held there by some spring clips. Perhaps a good dose of grease in the bearing / fork pivot points may get rid of the noise

I can't be sure what cured mine as I made sure I took all precautions when refitting it

Good luck!

------------------


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