Alternator Failure?
 

.Carrera.

But the belt is broken right?
If it overheated and you ended up driving home on what was left on your battery, then belt must have snapped.
Smoke?
How far did you drive it like that?
The oil temp may not rise in proportion to the head temperature from what Wayne has said in the past, so the oil temp may not be a good indicator in this particular case.
(because the oil will heat up long after the heads, no longer being cooled by the rush of air have heated up).

.

then, if the fan was working and your alternator went completely dead, then you just ran the car off on whatever was left of your battery charge. I don't know about the smoke and stuff--but I've had similar experiences. I believe my 914 acted similarly when the battery actually got disconnected and it was running off the alternator!

Seems like one or the other happened.

bump.... anyone else have any thoughts on this before I go in there taking stuff apart?

I know that I need to measure voltage to be sure.

The car started fine today and ran well in the garage, but the battery seems weak. It was raining like hell yesterday, so perhaps something got wet...

fwiw, I figure routine life of an alternator is 75k miles. Change it anyway.

yes, you need to measure voltage. With the engine running at about 2K, you should see about 14V at the battery as I recall (if you do a search, I had threads on this a year or so ago). If your battery is at around 12 with the engine running, I'd say the alternator is toast. And listen to Ron...you've been living on borrowed time anyway...

Yeah - 1500 - 2000 rpm, measure across the battery. If it's lower than 13.5 your alternator is likely weak, if it's higher than 14.2 or so you probably have a bad regulator.

Sonic: I had the same symptoms. It was the alternator. I had mine rebuilt at Foreign Alternators and Starters near the corner of Reseda and Parthenia in Northridge. $89 with a one-year warranty. It's been a couple of years, and no problems. They are a small shop, but do good work.

While you have it apart, now's the time to send your shroud and fan to Al Reed for polishing.

Good luck.

"I had mine rebuilt at Foreign Alternators and Starters near the corner of Reseda and Parthenia in Northridge. $89 with a one-year warranty."

You get what you pay for! The regulator alone is about $50. They've used the old regulator
which is highly prone to overcharge.

Why would anyone put a questionable rebuilt alternator in their car especially a Porsche
where the R/R is not real easy?

I just put a new one in my 85, rebuilt Bosch and I had them do the labor. Cost a few hunny, mostly labor, the alternator ran around $150 I think.

Got to wipe the dust off the ol' 101 Projects book one of these days......

Loren: So far it's been rock solid. Time will tell, I suppose. I can only imagine what you would have said if I had installed a new performance chip. Fortunately, it's only an alternator. :D

PS: Loren, I just remembered that when I picked up the alternator, I commented that the regulator looked new. The guy said he replaced it. So, either he lied and just cleaned it up to make it look new, or he did a quality job. I prefer to believe the latter. As I said, time will tell.

Thanks for the responses. Scottb, thanks for the tip on the place in Northridge. There is also a shop in Van Nuys that rebuilds and sells rebuilt alternators. I am going to pull it and send it to one of those places...

If you're considering Alternator and Ignition Supply in Van Nuys, be sure they have experience with this alternator. IIRC, I think I called them when mine went bad, and they sort of "hemmed and hawed" about whether they'd done them before. The guy in Northridge knew right away what it was, and even had a core in stock. AIS did an alternator for me when I had a Jensen Healey, and they did a good job. I'm sure either place will get you back on the road ASAP.

Are you going to let Al Reed do his magic to your fan and shroud while you have it apart?

"There is also a shop in Van Nuys that rebuilds and sells rebuilt alternators. I am going to pull it and send it to one of those places..."

We'll all keep are fingers and toes crossed for you! Hopefully if it fails, you'll not be
in an undesireable location. Also, if it starts overcharging, hope you have a spare
DME control unit to use, since it's one of the first 3.2 electronics to fail.

You might try Pep Boys. They could be a couple of dollars cheaper. They have
that unlimited warranty. Obviously, the R/R labor is not included. Since you're
a DIY, who cares how many times the alt. needs to come out.

The place in Van Nuys is called CAE. They quoted me $125 to rebuild my alternator...or $150 to buy a rebuilt one from them, with a $25 core charge. Warranty on either is 90 days. Takes one day for them to do a rebuild.

90 days? That doesn't inspire much confidence. Give FAS a call...they might even be open today. I think the turn-around on mine was a couple of days, but I wasn't in a big hurry (the P-car is the weekend toy).

Foreign Alternators & Starters
Address: 8652 Amigo Ave, Northridge, CA 91324
Phone: (818) 772-1700

"Warranty on either is 90 days"

Kinda like getting one at the junk yard! Have to love it.

Yeah true.

Loren...do you know anyone in South Bay that does alt. rebuilds? I live in Redondo....

If you're concerned about "low end" stuff, you might try these guys. http://www.socalaltandstart.com/index.html. They offer a three year warranty, but they were kinda spendy IIRC. You have lots of options.

"Loren...do you know anyone in South Bay that does alt. rebuilds? I live in Redondo...."

Two Options:

1. Call Pelican. They can probably provide you with one at a good price & warranty.
They should have an exchange program. Call Tom Gould.
2. Call some of the many Porsche shops in the South Bay and ask them.

Make sure that you get the lastest OEM regulator from Valeo/Paris Rhone
(no more aluminum fins). Pelican should stock this one.

Over charge
 

I am sure the alt light comes on with under charge. Does it come on with over charge?
Anyone?

Nope....

Alternator question
 

My car was at a shop being corner balanced aligned etc when the guy called me and said my alternator is bad. The battery died while refilling the oil after the change. They wanted $600.00 to replace the alternator so I decided to do it myself. I can handle this right? I recently rebuilt the engine and did all the work myself. The car has only been run to break in the engine and driven on the street enough to correct oil leak etc. Since I just rebuilt engine, it is entirely possible that I re-connected it incorrectly. The shop stated that the battery was not re-charging (new Interstate Battery) that much is true but didn't investigate if the connects were properly done.

I removed the alternator and took it too a shop who rebuilds these units. Today they called and said nothing was wrong with the alternator. I know something is wrong with the car as the battery can be re-charged (manually) and driven. the battery will go completely dead if I let it.

I will re-install the alternator this evening. Can anyone give me guidence on what to check and what to look for? I do have a mulitmeter. I'm really not skilled with voltage etc, so any basic information will be helpful. I know to check voltage at the battery but that is it.

Have a automotive electrical shop test the battery,i.e., put a load on it to see if it is kaput. Even a fairly new battery can go bad. Call the shop who told you that the alternator was bad and tell them the news and see what they have to say what the problem could be. Keep in mind that they made the wrong diagnosis.

If you do decide to tackle the R&R yourself...see here--->
http://www.pelicanparts.com/techarticles/911_volt_reg_replace/911_volt_reg_replace.htm

Wil

Sonic

Make sure you recharge your battery fully before reinstalling a rebuilt alternator.

An alternator is not designed to recharge a completely flat battery, so don't get someone to jump start your car. Doing this will only ruin your rebuilt alternator.

Fully charge battery....check to see if alt light comes on when ignition is turned on...important as the bulb is part of the charging circuit.

test battery at rest 12.5v
test battery at idle 13.0-13.5
test at 2500 rpms 13.5-14.5 MAX

too low at rest...bad battery
too low at idle...alt
too high at idle or 2500 rpms...most like a regulator

Porsche alts are not magic...local competent shops can rebuild them.

My 78 SC has the jumping tach indicating overcharging, right?

I changed out the reg for a new one, it seemed better but is back to overcharging again. The gen light comes on a little at idle. I checked charge rate..it starts at 12.5 or so, jumps up to 14.5, then spikes at 17. Could be the alt? My grounds are ok, and I checked belt tightness, and shims, although I am short one shim . Any other ideas before I pull the alt?

Classic symptoms of a bad alternator. It may have taken out your new regulator, too.

If it were my car, I'd pull both out and have a local rebuilder bench test them. While it's apart, now would be a good time to polish and powdercoat the fan and fan housing.

Good luck.

Spikes above 14.5 Volts are <b><i>ALWAYS</b></i> a problem with the regulator, or ground/power cables.

Re: Alternator question
 

Hey Groovy. What's happening?

RoninLB,

Symptoms are battery did not recharge after I put my newly rebuilt engine in the car. Battery is a new Interstate unit. Battery has been taken to Interstate and tested, it tested fine at Interstate. Local Porsche shop told me Alternator is dead. I took the alternator out myself after I picked the car up from the shop. I tool the alternator to an alternator/generator repair shop where they originally said alternator checked out fine. When I picked up the unit the technician told me the alternator had a "bad spot" and that could have caused the battery not to recharge.
Before my engine rebuild the tach did spike up on rev'ing the engine. I thought it odd but did not know the cause. For the rebuild, I used the original alternator. The tach still spiked up on reving the engine after the rebuild.
I will get the rebuilt alternator in the car this evening (weather has been hell here) and what I wanted to find out is what components should I check? Like I said I know to check the voltage to the battery like ASD did in the above post. How should I check the regulator? Can I check the regulator? The transmission ground cable looks like hell. Possibly a ground issue?
Are there any good automotive electrical books out there that focus on Porsche?
I have new SSI's with a Monte dual in dual out! Sounds groovy when it runs : (
Sorry for the rambling post. Thanks for the help!

Ground straps are often neglegted; get a new one and check the connection coming from the body to the negative battery post.

What's going to wear out in a regulator? It's just a couple of transistors diodes and resistors. If the alternator is tested after you put new brushes in it what could go wrong? It is definitely past the infant mortality stage.

Buy asap "101 Projects for Your Porsche by Wayne R Dempsey" from Pelican Parts. They've heard of this guy Dempsey before. On p61 is "Alternator Troubleshooting and Replacement"

12v electrics are basically all the SOS. If you understand an issue you can translate it to any similar system. Different books will explain and address the issue a bit differently once you get beyond the basic. Auto, marine, and aircraft 12v books all have something to offer. The issue eventually becomes what you want from your electrics beyond the basic. What electric install makes you comfortable beyond stock. I'm not a good example to follow because my basic premise is that our 911 electrics suck to start with. If you want some electric readings, per my suggestion, you're gonna start down a slippery slope. Maybe start with Dempsey's 101 Projects and then stop at a local speed shop for the $15-$20 elec books they have. If you get tickled it'll be text time.

For example of my attitude.. you need a good alternator ground. Our stock ground is the engine case. Bingo suck #1. It's good enough for the factory but it's not good enough for me.

Monty singing a cam with overlap is groovy music imo.

Thanks guys for the insfo, I pulled the fan and alt and reg today and I am taking to get bench tested and see where I am at tommorow. The alt came off the fan easily with a light tap on the screws. The hardest part was getting behind to pull the alt wires , kinda snug in there.

I polished out the fan some with good aluminum polish, and it looks pretty clean, but I am checking out the photos of ones on this site for ideas.
Hope the alt fix will solve the problem I have had.

Had my alternator(paris-rhone) bench tested, turns out it is fine. It has the internal vr ( duh...I didn't know) and I had an external vr plugged in too.
I had replaced that one sometime ago thinking it was bad...
since it was always there ( I have had the car 13 yrs) who'd have thought it was the wrong hookup?
Guess the two regs worked ok until the one on the alt heated up too much.
They are replacing that one, I have disconnected the external, and the alt will get new bearings just in case.
meanwhile I have a detailed fan and painted housing.
Hope all will be well when I put it back together.

OK got my alt and new internal voltreg back. Before i put it all together, a question- I seem to have a hard time getting the shims to lay flat and line up when screwing down the big fan nut. What up with that? Is there some trick to putting the shims back in right?

ASD: Use Vasoline or some Grease to stick the Shims together....then push them in place.

BTW... My 2nd rebuilt Alternator has worked like a charm. I kept the first one that they shipped with the bad diode. I am going to have this one rebuilt as a spare.