R32 New clutch chatter sound

[SkylineP]

Hello everyone, happy easter! 

I recently had my stock clutch and flywheel replaced with a clutchmasters 350 and lightweight flywheel. I've put about 150ish miles on it now and everything was super smooth but last night I started hearing a rattling noise at idle from around the gearbox. It goes away when taking up the slack in the clutch pedal. I've included a video with a red arrow indicating clutch slave movement(end is full engage to put into gear) and text indicating on and off pedal slack. Any help is greatly appreciated.

[MoMnDadGTR]

wow mate that doesn't sound good. doesn't sound like a release bearing at all so I would forget about that. something with the flywheel or pressure plates something is definitely wrong. wont be the gearbox the cars no moving. take it back to where the clutch was installed and get them to look at it. if you can do it yourself not a bad project during this covid shit. take the transmission off and inspect the clutch. from the video sounds like a engine bottom end issue so hard to tell from that. I would start by pulling the clutch, inspect, post some pictures on here of the plates, flywheel, etc. if its good put it all back together and see if sound is still around.  I honestly feel like I can hear the sound the entire time it is only muffled when you pick the slack up in the clutch. quick question has the 150 miles you put on it been clutch kicks and boost maniac or just sunday driving? sounds like a bottom end issue mate the video is misleading. check input shaft for miscolouring or wear and tear. if had clutches put in wrong on my dodger trucks and they don't last long at all if the clutch is not setup perfect and true. not to bash the clutch you bought but I see way better results from os giken, orc, Nismo coppers but that's just an opinion I am not a mechanic at all just a guy whos had tons of issues with skylines and cars haha seen quite a bit. ps drop your oil at same time just to make sure, if you find metal shaving and what not could be from engine.

[SkylineP]

Thanks for reply, yeah I had a shop do it all, and so going to take it back, I was thinking input shaft too but read they aren't supposed to knock so I'm not very sure. The 150ish miles have been mostly Sunday, I have been letting the turbo spool up but only to 3k before shifting, and not hard shifting either.

[SkylineP]

And its all stock rb20 so there's not much power being transferred lol

[BK]

On 13/04/2020 at 8:29 AM, MoMnDadGTR said:

wont be the gearbox the cars no moving.

It does sound like the gearbox, and could be an internal gearbox bearing like the input shaft. Could be release bearing but surely that was changed with clutch. When the car is stationary the gears inside your gearbox are still turning remember ? They are in constant mesh. Noise gets worse when clutch pedal out and engaged points to box. Anyway box needs to come out as it could be anything.

Engine bottom end noise wouldn't be affected whether clutch is in (disengaged) or out (engaged), it would be constant.

[GTSBoy]

Input shaft bearing is the number one suspect.

As BK said - any gearbox makes rollover noise when the engine is idling and the clutch is engaged. (NOTE THAT "ENGAGED" MEANS THAT THE CLUTCH IS TRANSFERRING POWER - NOT THAT THE CLUTCH PEDAL IS PUSHED - just in case of the usual confusion. f**k the use of "in" and "out" to describe what state the clutch is in. What the f**k do those mean anyway?)

[BK]

1 hour ago, GTSBoy said:

(NOTE THAT "ENGAGED" MEANS THAT THE CLUTCH IS TRANSFERRING POWER - NOT THAT THE CLUTCH PEDAL IS PUSHED - just in case of the usual confusion. f**k the use of "in" and "out" to describe what state the clutch is in. What the f**k do those mean anyway?)

? Exactly

[SkylineP]

1 hour ago, GTSBoy said:

Input shaft bearing is the number one suspect.

As BK said - any gearbox makes rollover noise when the engine is idling and the clutch is engaged. (NOTE THAT "ENGAGED" MEANS THAT THE CLUTCH IS TRANSFERRING POWER - NOT THAT THE CLUTCH PEDAL IS PUSHED - just in case of the usual confusion. f**k the use of "in" and "out" to describe what state the clutch is in. What the f**k do those mean anyway?)

Clutch in would mean pedal pushed in, and out would mean pedal out, 

[SkylineP]

Thanks for the help everyone 

[BK]

Good luck mate and let us know the culprit

[SkylineP]

35 minutes ago, BK said:

Good luck mate and let us know the culprit

Thanks, will do. So I've been reading, can lightweight flywheels make the bearing louder? Also could it possibly be the flywheel bolts are possibly not tightened and came loose, or too long as i read some people having to cut down new bolts from kits to properly seat?

[BK]

Probably not. Your flywheel is attached directly to your crank, spinning with your motor constantly, which would mean noise constantly. Your noise is whether the clutch is engaged or not.

When clutch is engaged the input shaft bearing has a load on it which it does not have when clutch is not engaged, hence the suspected input shaft bearing failure. Release bearing is the opposite, no load when clutch is engaged, so that's why it's probably not that and also no noise in this condition.

You have to pull the box out.

[GTSBoy]

1 hour ago, SkylineP said:

Clutch in would mean pedal pushed in, and out would mean pedal out, 

And, from a blonde-behind-wheel perspective, that would be correct. But from a mechanical engineer's perspective (which is the correct one), "clutch in" means that the clutch is actively transferring power, and "clutch out" means that it is not. "Out" being the same as "out of circuit" in an electrical sense.

Hence why I tiraded, because the lack of clarity of language in these problem descriptions is a pain in the arse.

[GTSBoy]

23 minutes ago, BK said:

You have to pull the box out.

Or just live with it, because it doesn't sound that bad to me. My RB25 box sounds like a bulldozer in motion and has done so for 8 years, and probably for 8 years prior to me owning it.

[BK]

He has to pull the box out if he wants it fixed. If it is the input shaft bearing and you could live with the noise, yeah it could last years without anything really bad happening.

Something suss about it only doing it after a clutch change, like stress being put on input shaft when removing the box, possibly damaging it.

[GTSBoy]

Oh, yeah. Absolutely. Except that frequently these things go unnoticed until something like a clutch change. Then, when alerted to the fact that there are mechanical items under the car, the noise gets noticed when crouching down to look, and accidentally hear.

[SkylineP]

34 minutes ago, GTSBoy said:

Oh, yeah. Absolutely. Except that frequently these things go unnoticed until something like a clutch change. Then, when alerted to the fact that there are mechanical items under the car, the noise gets noticed when crouching down to look, and accidentally hear.

No it's a new noise, I park it between a garage and a fence everyday and after I could tell right away it didnt sound right. I'm the type that has the window down radio off listening to sound of my car. Lol thanks for roasting me on my lack of correct terminology.

[GTSBoy]

I don't care if you use incorrect terminology, so long as we understand what it is that you mean. "Clutch pedal depressed" is much more informative than "clutch in".

[SkylineP]

46 minutes ago, GTSBoy said:

I don't care if you use incorrect terminology, so long as we understand what it is that you mean. "Clutch pedal depressed" is much more informative than "clutch in".

?? I'll be more descriptive next time. Thank you.