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Registered
Join Date: Jul 2005
Location: Houston, Tx.
Posts: 139
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1985 911 lights varying brightness
My 1985 911 lights (inside / outside car) brightness vary. It's scary to me. I keep thinking maybe they are going to go out.
The main drive belt at idle appears to not be real smooth. When you accelerate it apears to get tight. Is there an adjustment to tighten the belt. And could this be the problem? The alternator appears to be putting out steady current? Is this normal as the lights only dim and then return normal and they do not go all the way down but the fluctuation I am not use too. Any input / tips would be appreciated. Thanks & best regards, Booney1golf 1985 Porsche 911 Carrera Targa - No substitute |
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12-17-2005, 10:04 AM
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Whoopsies I was banned!!!
Join Date: Sep 2005
Location: Trying to Escape from FLA
Posts: 4,596
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Is it possibly the alternator voltage regulator?
I mention this because I suffered from the very same thing. I had the voltage regulator replaced and voila! No more funny business with the light show. Regards, Carlton |
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12-17-2005, 12:00 PM
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Registered
Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,456
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typical with their 90A alternators. it's the reg, but the brushes on the reg wear grooves into the commutator in the alt, and the comm is very thin. so just popping a new reg in is at best, a patch.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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12-17-2005, 12:21 PM
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Whoopsies I was banned!!!
Join Date: Sep 2005
Location: Trying to Escape from FLA
Posts: 4,596
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Uh oh! The patch is most evil as it gives the appearance of being a friend! Bad Esel, bad Esel!
Guru John, many thanks on your additional insight! In sharing it you may have possibly prevented the posting of a learner from stranding another learner some time down the road! Also in sharing it, you may have possibly prevented in me stranding myself down the road! Regards, Carlton (Note to self, check those alternator commutators out) |
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12-17-2005, 01:09 PM
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Registered
Join Date: Jul 2005
Location: Houston, Tx.
Posts: 139
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So if I understand you, inorder to properly fix the problem correctly the alternator and the voltage regulater shoudl be changed at the same time.
Thanks again, Booney1golf 1985 Porsche 911 Carrera Targa - No substitute |
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12-17-2005, 09:10 PM
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Senior Member
Join Date: Jun 2000
Location: N. Phoenix AZ USA
Posts: 28,943
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Booney, (name pls)
Take a digital volt meter and check your voltage. Then leave it hooked up somewhere in the interior of the car and drive. Watch the voltage and record the readings. I had the same thing and it was the regulator going full tilt and sending the voltage up to 16 volts. The normal voltage should be from 13.5 to 14.5 or so, and over this is too high. Will overcharge the battery as well. This is a good way to burn out anything on the car that contains electronic parts. This includes your very expensive DME computer, DME relay, stereo and the rest of the electronic bits. The regulator and diodes are built into the alternator. If this is the problem and you have it overhauled, have them replace all the bearings, brushes and regulator pack. I took my alternator out and went to a local "Mom and Pop" shop. They gave it back to me "like new" for about $75 in a half of a day. It was still working well 4 years later when I sold the 3.2 for my transplant. Joe A
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2013 Jag XF, 2002 Dodge Ram 2500 Cummins (the workhorse), 1992 Jaguar XJ S-3 V-12 VDP (one of only 100 examples made), 1969 Jaguar XJ (been in the family since new), 1985 911 Targa backdated to 1973 RS specs with a 3.6 shoehorned in the back, 1959 Austin Healey Sprite (former SCCA H-Prod), 1995 BMW R1100RSL, 1971 & '72 BMW R75/5 "Toaster," Ural Tourist w/sidecar, 1949 Aeronca Sedan / QB Last edited by Joeaksa; 12-18-2005 at 12:21 AM.. |
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12-18-2005, 12:16 AM
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Registered
Join Date: Jul 2005
Location: Houston, Tx.
Posts: 139
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Thanks for the additional advice.
Due to all of the valuable info above I think I am just going to go ahead and have the alternator rebuilt and replace the voltage regulator at the same time. Best regards, Daniel Womack (Booney1golf) 1985 Porsche 911 Carrera Targa - No substitute |
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12-18-2005, 05:46 AM
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Registered
Join Date: Aug 2002
Location: Galivants Ferry, SC
Posts: 10,550
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Look at my 1985 Carrera alternator/ VR R&R procedure in the Tech article section of Pelican...says the same thing. Most likely a bad VR and the wear grooves into the thin slip ring contact area needd replacing or rebuilding too... as stated, almost certainly...
Wil
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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12-18-2005, 11:12 AM
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