Changing the Voltage Regulator in Alternator - Alfa Romeo Bulletin Board & Forums
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post #1 of 7 (permalink) Old 02-10-2008, 04:32 AM Thread Starter
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Changing the Voltage Regulator in Alternator

We are repairing GTV682 Bill's 164 with bent valves this weekend and while car apart we are doing some side repairs in engine bay such as installing a rebuilt starter, rebuilt cooling fan motor, new low speed cooling fan resistor, new a/c heater blower motor and a new voltage regulator in alternator.

We would have replaced bearing in a/c clutch pulley too but car has new compressor assembly already installed. Lucky us as that was one less item to ZERO time.

Here is picture of old and new voltage regulator for alternator. As you can see brushes worn quite a bit. We had to change broken radio noise suppressor, too.
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Alfa Semi-Daily driver: USA model - BB2 1991 164S Black Beauty II ALFISTO [U]

[U] BB1 1991 164L w/S engine and A/T now excess to inventory [U]

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post #2 of 7 (permalink) Old 02-10-2008, 04:37 PM
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what a difference

Wow! What a difference.
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post #3 of 7 (permalink) Old 02-17-2008, 08:23 PM
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24V voltage regulator

24V alternator and voltage regulator are slightly different from the pictures that Steve posted. The 24V alternator has a plastic cover at the back of the alternator and it has to be removed to get to the voltage regulator. But in order to take the plastic cover off, the front exhaust manifold heat shield need to be removed first. In the first picture, you can see the heat shield was drop down and the alternator back plastic cover was move to the side. The A/C hoses are somewhat in the way. The second pic shows the voltage regulator as mounted on the back of the alternator. The lower two pics show the voltage regulator.

Why I pulled the voltage regulator? The car was showing inadequate electrical power supply symptoms (even with a new battery) - voltage dropped too much whenever I switched on some additional loads. I pulled the voltage regulator today and cleaned all the electrical contacts that I came across. I put the old voltage regulator back (don't have a new one on hand) and some preliminary measurements show that the charging system is working much better now. It was charging at ~14.6V with engine idling and it still stayed at ~14V with most electrical accessories turned on (before cleaning, it dropped below 12V)!
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post #4 of 7 (permalink) Old 07-04-2019, 03:28 AM
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Quote:
Originally Posted by BlackAlfa View Post
24V alternator and voltage regulator are slightly different from the pictures that Steve posted. The 24V alternator has a plastic cover at the back of the alternator and it has to be removed to get to the voltage regulator. But in order to take the plastic cover off, the front exhaust manifold heat shield need to be removed first. In the first picture, you can see the heat shield was drop down and the alternator back plastic cover was move to the side. The A/C hoses are somewhat in the way. The second pic shows the voltage regulator as mounted on the back of the alternator. The lower two pics show the voltage regulator.

Why I pulled the voltage regulator? The car was showing inadequate electrical power supply symptoms (even with a new battery) - voltage dropped too much whenever I switched on some additional loads. I pulled the voltage regulator today and cleaned all the electrical contacts that I came across. I put the old voltage regulator back (don't have a new one on hand) and some preliminary measurements show that the charging system is working much better now. It was charging at ~14.6V with engine idling and it still stayed at ~14V with most electrical accessories turned on (before cleaning, it dropped below 12V)!

Thank you so much. I had this problem of overheating when the A/C was ON. I found out it happens because alternator output is low when electrical load is high (goes to low 12s in Voltage), then the radiator fan spins slower than required. So the temp rises.

I anticipated a total removal of the alternator and replace its internal regulator. But thanks to you, I managed to scrub clean the 3 contacts and push them a little bit forward with pliers so they contact well. Now with headlights ON, AC ON and blower fan at full speed and radiator fan at high speed, it still stays above 12.9V.

I have to replace this part but for now, this is manageable. Thank you once again.
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Current:: '96 Alfa Romeo 164 Super V6 24V || '93 Alfa Romeo 33 1.5IE || '74 Holden HQ SS || '87 Oldsmobile Custom Cruiser 5.0 V8 || '72 Volkswagen Beetle || '97 Nissan Sunny 2.0D
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post #5 of 7 (permalink) Old 07-21-2019, 01:26 PM
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Hi,

Have alternator off, 164 24v, and my repair kit includes a lot more than just the regulator. For example, do I need to open it up further to add the supplied extra two pairs of bushes somewhere? If so, how is the best way of doing it?
Thanks.
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post #6 of 7 (permalink) Old 07-21-2019, 08:07 PM
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I have overhauled about 3 alternators and they all had only 2 brushes. So 164 alternator can't be so unusual. I think those extra brushes would go in to the regulator once it's brushes wear off.
You might have to de-solder and remove the worn out brushes and re-solder the new ones in.

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Current:: '96 Alfa Romeo 164 Super V6 24V || '93 Alfa Romeo 33 1.5IE || '74 Holden HQ SS || '87 Oldsmobile Custom Cruiser 5.0 V8 || '72 Volkswagen Beetle || '97 Nissan Sunny 2.0D
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post #7 of 7 (permalink) Old 07-23-2019, 09:49 AM
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Originally Posted by kuseetha View Post
I have overhauled about 3 alternators and they all had only 2 brushes. So 164 alternator can't be so unusual. I think those extra brushes would go in to the regulator once it's brushes wear off.
You might have to de-solder and remove the worn out brushes and re-solder the new ones in.

Sent from my SM-J730F using Tapatalk
That makes sense. Thanks.
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