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morghen
Joined: 21 Jan 2005
Posts: 9102
Location: Romania
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 Posted: Wed May 11, 2016 7:02 am Post subject: Torque tube bearings whine or clutch bearing? |
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This is about my S1 931.
I'm about to start on a 5000km trip and there is a whine sound that seems to come from under the car. Its audible when decelerating close to idle, i mean i'm driving in the city and i let it roll on engine break until its under 2000rpm then drop it to a lower gear.
The whine is most audible when the rpm drops lower than 2k and the car is decelerating at its natural pace.
The whine is also slightly audible at idle if i rev it to 2k and let it settle.
The whine is not audible if i break during deceleration thus decelerating the main shaft at a faster rate than just letting it roll.
The clutch bearing is also noisy, when i press the clutch it whines.
I need to know your clutch bearing failure experiences as well as torque tube bearings fail experiences.
If you think there is a way to isolate where the problem comes from i'm all ears.
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Qik Nip
Joined: 16 Jan 2015
Posts: 130
Location: Kentucky
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| Posted: Wed May 11, 2016 9:17 am Post subject: Re: Torque tube bearings whine or clutch bearing? |
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| morghen wrote: | This is about my S1 931.
I'm about to start on a 5000km trip and there is a whine sound that seems to come from under the car. Its audible when decelerating close to idle, i mean i'm driving in the city and i let it roll on engine break until its under 2000rpm then drop it to a lower gear.
The whine is most audible when the rpm drops lower than 2k and the car is decelerating at its natural pace.
The whine is also slightly audible at idle if i rev it to 2k and let it settle.
The whine is not audible if i break during deceleration thus decelerating the main shaft at a faster rate than just letting it roll.
The clutch bearing is also noisy, when i press the clutch it whines.
I need to know your clutch bearing failure experiences as well as torque tube bearings fail experiences.
If you think there is a way to isolate where the problem comes from i'm all ears. |
To diagnose the throwout bearing, with the car running and in neutral engage and disengage the clutch. If it makes noise when the clutch pedal is depressed, the throwout bearing is the problem. If that is not the problem with the car running, in neutral and with the clutch engaged (foot off the pedal) it you hear noise it is either the transaxles' inputshaft bearing, or the torque tube bearings. Unfiortunately, the only way to be sure which is to take it apart, although you may be able to lie under the car on jack stands and locate where it's coming from. Good luck.
Rick
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'79 NA 924 Land Speed Car
Bonneville G/CPRO record @ 149.825MPH
Arkansas Mile G/CPRO record @ 138.0 MPH
Great Lakes SCCA SM points champion '09,'10,'11 |
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morghen
Joined: 21 Jan 2005
Posts: 9102
Location: Romania
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| Posted: Wed May 11, 2016 5:43 pm Post subject: |
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Throwout bearing is deff whining and making other noises but thats not what i'm worried about..or should i? 
I think its the needle bearing inside the flywheel that is making that sound as its audible standing with or without clutch pedal pressed AND rolling(decelerating in lower gears)
I made a recording and modified it a bit so the whine is a bit more evident.
https://youtu.be/hLuvK0xxPgY
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Mike9311
Joined: 14 Dec 2004
Posts: 1798
Location: Chicago-ish
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| Posted: Thu May 12, 2016 3:22 am Post subject: |
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| morghen wrote: | Throwout bearing is deff whining and making other noises but thats not what i'm worried about..or should i?
I think its the needle bearing inside the flywheel that is making that sound as its audible standing with or without clutch pedal pressed AND rolling(decelerating in lower gears)
I made a recording and modified it a bit so the whine is a bit more evident.
https://youtu.be/hLuvK0xxPgY |
Can you get FFT?
At least from the torque tube side of things you could isolate if they are an issue. I can't remember if all the torque tube configs have the 6006 bearing but for the 6006 at 1000 rpm (double these for 2K)
Inner ring defect is 107 Hz
Outer ring defect is 76.33
The element or ball is 48.41
Inner ring 16.67 (this is your speed 16.67 * 60 = 1K)
Cage rotational speed 6.94
Element or ball speed 96.83
You might get a lot more depending on other factors..alignment and so on.
In my family lately, we have been lifting our cars up and listening to them while running with a stethoscope (screwdriver works) in different spots around the car. Beforehand we take bets which wheel bearing it is, then listen. This may be your best bet. I 'dislike' noise like this because sound travels all over the car and couples with other noises. Doesn't sound like the tube bearings though....
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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Mike9311
Joined: 14 Dec 2004
Posts: 1798
Location: Chicago-ish
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| Posted: Thu May 12, 2016 3:38 am Post subject: |
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As far as I know the size for the needle bearing is below and feel free to correct if this isn't the size. I looked it up quick instead of wandering through my parts
The pilot needle bearing is HK 1616 2RS
some of the frequencies are close and might couple with the tube bearings (running speed and cage)
@1000rpm
running speed 16.7 Hz
cage 7.41
roller/needle speed 74.1 (about its axis)
inner ring defect 166.7 (this is the driveshaft surface since needles run on it)
outer ring defect 133.3
element/needle defect 148.1
Also, back to the tube bearings, the frequencies could vary due to internal clearance (especially if C5 version) and no preload. The balls could be speeding up and slowing down too as they run through a load zone if there is any mild bend in the shaft. I am working on something right now and about to confirm how true a tube might be. Possibly today but this is off topic.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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morghen
Joined: 21 Jan 2005
Posts: 9102
Location: Romania
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| Posted: Thu May 12, 2016 6:12 pm Post subject: |
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thank you very much !
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Qik Nip
Joined: 16 Jan 2015
Posts: 130
Location: Kentucky
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| Posted: Sun May 15, 2016 12:00 am Post subject: |
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| morghen wrote: | Throwout bearing is deff whining and making other noises but thats not what i'm worried about..or should i?
I think its the needle bearing inside the flywheel that is making that sound as its audible standing with or without clutch pedal pressed AND rolling(decelerating in lower gears)
I made a recording and modified it a bit so the whine is a bit more evident.
https://youtu.be/hLuvK0xxPgY |
When the clutch is engaged, there is no relative motion between the input shaft nose and the pilot bearing. They would be rotating together. So generallty speaking there wouldn't be any noise. If however the pilot bearing has disentegrated, the input shaft can wobble when the clutch is depressed because there's no bearing to keep it centered. (Remember the pilot bearing and the input shaft nose are there to keep the clutch centered). BTW, I had a pilot bearing fail on a 924 years ago and that failure resulted in the input shaft nose litterally wearing away to a nub.
Rick
_________________
'79 NA 924 Land Speed Car
Bonneville G/CPRO record @ 149.825MPH
Arkansas Mile G/CPRO record @ 138.0 MPH
Great Lakes SCCA SM points champion '09,'10,'11 |
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Mike9311
Joined: 14 Dec 2004
Posts: 1798
Location: Chicago-ish
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| Posted: Sun May 15, 2016 1:47 am Post subject: |
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Quote: " I had a pilot bearing fail on a 924 years ago and that failure resulted in the input shaft nose literally wearing away to a nub"
This was my concern as well if this is happening. The inner race diameter of the pilot bearing, which is available, is 16mm. The drive shaft could be turned then ground by someone competent to hold 0.0001" or .00254mm and the inner race installed preferably with a small amount of interference and proper loctite (Loctite for shrink fitting parts, not thread locker)
Years ago for a friend, I made a inner race for a needle bearing in a truck manual trans. Hardened it and installed after sizing the trans shaft for the custom inner race. Drove it for years after that with no issues.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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morghen
Joined: 21 Jan 2005
Posts: 9102
Location: Romania
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| Posted: Sun May 15, 2016 2:32 am Post subject: |
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The car will be driven 90% at 2800-3200RPM for the next 5000Kms...hoping nothing will wear and no problems.
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Mike9311
Joined: 14 Dec 2004
Posts: 1798
Location: Chicago-ish
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| Posted: Sun May 15, 2016 10:02 am Post subject: |
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| morghen wrote: | | The car will be driven 90% at 2800-3200RPM for the next 5000Kms...hoping nothing will wear and no problems. |
Nice! Jealous I am
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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morghen
Joined: 21 Jan 2005
Posts: 9102
Location: Romania
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| Posted: Sun May 15, 2016 7:11 pm Post subject: |
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I'll post pictures as i go. I will be taking both my GTS wannabe car and this S1.
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Mike9311
Joined: 14 Dec 2004
Posts: 1798
Location: Chicago-ish
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| Posted: Mon May 16, 2016 12:52 am Post subject: |
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| morghen wrote: | | I'll post pictures as i go. I will be taking both my GTS wannabe car and this S1. |
sweet, you take nice pics
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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