[ds968]

 

Did the ringing sound in the alternator disappear? I suspect that the gremlin that was making the noise in your muffler simply relocated to the alternator when he (all shop gremlins are male, by the way) heard you were changing the exhaust system.

 

No, the ringing is still there for the first couple of minutes on morning starts.   And since with a stethoscope placed on everything on the engine of which I could think - the SC, the pulleys, the drive belts cover, the starter, the AC compressor, ,  - the most pronounced ringing by far seems to be coming from the alternator, I presume that must be it. ( can't say that with certainty I guess, but just following the sound is best I can do / think of..)   So could be bearings which are stating to wear out and once they warm up they quiet down.  They stay warm for a looong time though, because there have been 12 + hour periods during the daytime when I re-start the car and it's quiet.   Like I said, ghouls and ghosts and gremlins roam during the cold nights and mess up the bearings for my morning starts ..            

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[az968]

I'm having the bearings replaced in my alternator right now because of a noise when cold, picked up with a stethoscope.  When I go pick up the car tomorrow I'll ask my mechanic if temperature makes any difference in the bearing noise. Also getting commutator bushings refreshed, new voltage regulator since he is in there and it is the original one..

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[ds968]

Great, thanks Bob, let us know what he says . Also, does he think noisy bearings ( albeit briefly so ) could impact the amps the alternator sends out ?

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[Waylander]

we have that covered over here.

 

Voltage regulator was the same as the Ford Granada of the same Era, they cost about $15 on ebay

 

the Bosch Number for that part

 

1 197 311 040

 

http://www.ebay.com/itm/NEW-BOSCH-REGULA...SB&vxp=mtr

 

the whole alternator is bosch number 0 120 468 005

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[az968]

If only I knew that two days ago.......

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[ds968]

So the new battery is in ( the local Interstate shop was great .. no questions asked, no receipt needed, they just took the old battery and gave me a new one , even without the usual prorated cost deference - just a straight out exchange ..maybe since the old one was less than 5 months old they figured no néed to hassle with anything. So now I have to wait for a very cold morning and see how the car crankis on starts but that may be a while, a majors heat wave is predicted for the next couple of weeks.


On a separate note , I took the voltmeter with me and tested a bunch of batteries which were on the shelf at Interstate's location , as well as at Auto Zone . Not a single one of them was more than 12.4 , the majority were between 12.25 and 12.3 . None below 12.2 though . So I don't know whether my voltmeter is very accurate or if that's the norm for " fully charged " shelf batteries .

After driving the whole day yesterday I checked my new battery and it read 12.3. This morning the reading was also 12.3

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[flash]

could be a bit of both.  depending on the store, the battery could have been sitting there for a while.

 

when was the last time you changed the battery in your voltmeter?

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[ds968]

lol, funny you should ask that ...I changed the voltmeter battery just a few days ago , because the old one was dead as a door nail ( I had not used that device in probably five years or more )

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[az968]

Talked with my mechanic when I picked up my car yesterdau. Rebuilt the alternator ($190) since it sounded like bearings were going out, also new voltage regulator ($40). The real noise was from the balance shaft bearings which were replaced also. But while checking on cause of noise discovered the alternator issue. His thoughts were everything starts with the battery (pun intended). If not delivering enough CCA the engine will be slow to crank. If battery is low, and grounds are good, likely the alternator. To properly test this, he mentioned a tool that measures both voltage and amps at the same time. Alternator could be producing voltage but not enough amps, caused by a component I can't recall name of. He offered to try to diagnose over the phone if you want to call him.

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[ds968]

My mechanic said his volts and amps equipment is very old so he's not 100% sure if the readings are precise / accurate or if they might be off . It's a big-ass panel about 4 x 4 ft ( including the roll cart it's on ) and it's digital so not really ancient yet, but he suggested I should find a place with more updated equipment to test the charging system's amps output . After the new regulator was installed the device showed 13.7 V , and 47 amps output after starting the engine. He thought 47 amps is rather low but did not know what specs our alternators are. I subsequently searched and it shows they're ( OE ) 115 amps. I'll monitor this new battery charge for a month or two and see if it drops below the 12.3 my voltmeter reads . If it does drop, then I'd guess the alternator is not fully doing its job. If it stays at 12.3 I suppose I need not worry about the alternator just yet . But that ringing noise is driving me batty , I might replace the alternator just for that reason. I'm hoping of course my mechanic can confirm that's absolutely, positively, without a doubt the source of the noise, because replacing the alternator with the SC assembly in the way , at least as far as my mechanic is concerned , means not just pulling the SC forward as Flash said , but completely removing it out of the way. So I'm probably looking at a $ 2,000 + job ..

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[Waylander]

CS, SPORT Alternator 90A, Coupe Cab Alternator 115A

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[ds968]

So ignorance-based question , but if an alternator is 115 amps , does that mean that in perfect condition it should be sending 115 amps to the battery , or that's not how things work and the charge it sends out is a smaller amps number ..if so. what fraction is typically normal ?

Also, if the alternator is operating at less that optimum capacity , how long would it take for the battery to show a drop in volts , say, from 12.35 to may be 12.3 or 12.25 ? A day, two , a week , a month.. ?

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[flash]

no - and yes

 

if the regulator senses a need, then the alternator can provide up to 115 amps of power.  however, unless you are generating the need, then it won't.  you would have to turn on every accessory, and be in the most inclement of conditions, in order to do that though.

 

how long it takes would depend on the specific gravity of each of the cells, the size of the cell, and the output of the alternator.

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[ds968]

This battery is keeping a consistent 12.4 V reading ( on my external voltmeter instrument ) , so it's materially different than the 12.01-11.95 reading on the previous battery . But since I have a new voltage regulator it's difficult to say if the old one was not very effective ( the brushes were worn almost all the way down ) , or if it was the battery that might have had a bad cell.

Regardless, I'm still waiting for that cold weather at night to hit us so I can test the cranking speed on the morning starts. Looks like we might get lucky by Friday , the last week or two someone apparently decided to borrow Dubai's summer climate and import it to the Bay Area.

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[Waylander]

Found a local auto electrical store that sells voltage regs that fit all 944 968, $9 inc tax


So a new one just went in my car, think I can post them to the US for less than you paid

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[Bulti]

Hmm, is it the same as stock or a different one that fits and works?

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[ds968]

The car sat for three days while I was out of town for the weekend, and the first cold temp start this morning ( overnight temps were in the low 50s ) was perfect.   Strong, fast crank, immediate start, so it was definitely a weaker battery which caused the problem, although as I mentioned before, since I simultaneously changed the regulator not sure how much that contributed to the old battery's voltage and/or amps weakness.       

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[flash]

likely the worn regulator caused the alternator to fail to properly charge the battery.  doing that over time lowers the battery's ability to fully charge.  for example, every time you kill a battery, it loses a portion of its ability to charge (as much as 5%).  how soon you rev the engine after jumping it has an effect too.  high rpms should be avoided until the battery is charged, due to the added heat in the alternator.

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[Waylander]

Hmm, is it the same as stock or a different one that fits and works?

They are not Bosch if that's what you are asking, but for €8 as a price against the Porsche replacement at €200


I can get Bosch if you want one Phillipe

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[Bulti]

Thanks, but mine is still working fine so far. I was just wondering, if so cheap, where does it come from and what about the quality? China?

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