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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Rear End Howl
Hi,
I have a Howl in the rear of the car somewhere and am trying ti find it. I wiggled a wheel today and thought the bearings felt loose to me. I have this howl that gets real loud at 2000-2500. It continues from 2500 but as you go faster and everything gets noisier it is not as noticeable and changes to a higher pitch. It is real bad from 2100-2500. I wold think it is a wheel bearing, except that when you engega the clutch while running down the road at 70mph, the sound disappears completely. If it was a wheel bearing, I would think it would keep singing. Any ideas? Thanx! Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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sudo apt-get purge 930
Join Date: Jul 2006
Location: Brandon, FL
Posts: 4,838
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When my rear bearings went south it went from whining/howling to humming/throbbing to a loud clunking noise. It changed around at will.
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Mark 1979 930 Euro ***GONE AND DON'T MISS IT AT ALL*** "Worrying about depreciation on your car and keeping mileage down is like not ****ing your girlfriend so her next boyfriend finds her more appealing" --clutch-monkey |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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I was wondering if bearings can go silent when you engage the clutch?
Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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sudo apt-get purge 930
Join Date: Jul 2006
Location: Brandon, FL
Posts: 4,838
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Mine didn't go silent when pressing the clutch every time. They went silent when they chose to do so. If yours stops when the clutch is pressed I would say it's not the wheel bearings.
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Mark 1979 930 Euro ***GONE AND DON'T MISS IT AT ALL*** "Worrying about depreciation on your car and keeping mileage down is like not ****ing your girlfriend so her next boyfriend finds her more appealing" --clutch-monkey |
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Registered
Join Date: Jan 2007
Posts: 1,079
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Yeah, it was explained to me that a wheel bearing makes a howling noise.
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Slantnose from HELL
Join Date: Dec 2004
Posts: 888
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Possibly while in gear appliying load to the bearing would cause the howl. Then when you let the clutch out the car would coast removing bearing load eliminating the noise temporarily. I'm sure in time the noise would eventually come back but much greater amounts as well as more damage. More than likely but then again just a thought.
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It changes from time to time..... |
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Registered
Join Date: Aug 2007
Location: The Golden State
Posts: 1,533
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Les, I had a right rear bearing going out.
It starts off with a very light high pitch hum, then progresses to the point where you think a Apache Helicopter is following you at various speeds. In it’s later stages, the sound is more prevalent during cornering. But since it is progressive, you will not really detect it until your daughter rides in the car and asks why the radio is so loud ![]()
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Rod... 2010 - 997 PDK, Black on Black, Daily driver. 1987 - 930 Grand Prix White, Not looking for crazy HP, just harmony! |
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Registered
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Could it be somthing as easy as a loose fanbelt?
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78’ SC 911 Targa - 3.2SS, PMO 46, M&K 2/2 1 5/8” HEADERS, 123 DIST, PORTERFIELD R4-S PADS, KR75 CAMS, REBEL RACING BUSHINGS, KONI CLASSICS |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Quote:
Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Hmmm, I've never heard a loose fanbelt on a Porsche, but this sure sounds like a bearing. I don't hear it free revving it. I also think it's speed related not rpm necessarily. I'll check this tomorrow. Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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Slantnose from HELL
Join Date: Dec 2004
Posts: 888
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Other items to consider is the throw out bearing or the input shaft bearing. Just guessing, I'd rather it be a wheel bearing than to other two.
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It changes from time to time..... |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Quote:
Hi, Yeah, I've considered all those also. Everything is new except the wheel bearings. That doesn't mean that I couldn't have problems with them though. The input bearing and throw out bearing have maybe 1000 miles or less. Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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Registered
Join Date: Sep 2005
Location: Erie, PA. Fort Myers Shores , Fl.
Posts: 673
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Les,
I think that the release bearing will show itself to be bad at any RPM and any speed. If you apply any pressure on the bearing at all and the noise goes away, then the bearing is potentially bad. On the other hand, if the release bearing is totally shot, it will grind when pressure is applied. I don't believe the wheel bearing is the culprit. You seem to have eliminated that with your on-throttle off-throttle test. Most of the load on the wheel bearing at cruising speed is from gravity, and the weight of the car, not the torque of the engine. Since the noise goes away by disengaging the clutch, I would say that the problem will be found elsewhere. My guess (albiet amateur) is that the problem lies between the mechanisms you are affecting when you engage and disengage the clutch: clutch disc, flywheel, and input shaft of the tranny. I think you have all but eliminated the flywheel because you said the noise doesn't show itself when you free rev. A loose flywheel will vibrate while free revving, and will quit vibrating when you hold in on the clutch because you are effectively pushing the flywheel into place with your foot. A bent or out of balance flywheel will always vibrate at a certain RPM regardless of whether the clutch is engaged or not. The clutch disc itself doesn't seem to be it either. The disc is clamped in place while cruising, and is somewhat free spinning when disengaged. When clamped in place, it is part of the flywheel (so-to-speak), and can't make noise on it's own. That leads me to suspect an internal tranny problem. Once again, I am a rank amateur, and believe me there are far more senarios that could explain your dillemma. I only hope I am wrong, and that the real experts chime in and shoot big holes in my theories. Good luck with it! Drew |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Quote:
Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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A fellow Pelacanite
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It could even be the CV's.
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG. Fitting - New service kit. Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head. 1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods. Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit. http://www.danasoft.com/sig/Iamnotanumber.jpg |
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Forced Induction Junkie
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Quote:
A loose wheel bearing will also generate a groaning kind of noise when the brakes are applied with moderate pressure at highway speeds.
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Dave '85 930 Factory Special Wishes Flachbau Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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I had the CV's greased at the same time as everything else.
Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Quote:
Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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Registered
Join Date: Sep 2005
Location: Erie, PA. Fort Myers Shores , Fl.
Posts: 673
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When you say "engaged" do you mean your foot is on or off the pedal?
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Macht Schnell
Join Date: Jun 2003
Location: PSL, FL
Posts: 861
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Quote:
Engaged to me is my foot is holding the Clutch down, foot to the floor. Les
__________________
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT |
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