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Vintage Alternator 1972 142E

xmlhack

Member
Joined
Dec 9, 2005
Location
Palm Bay, FL
I took my bosche alternator and had it checked out. I went to an old school auto electric place. Not autozone or oreilly's, etc. The alternator is putting out 14 volts on the bench. but i only get 11.2 volts in the car. i dont see a voltage regulator on the fender well. Theres only two wires going to the alternator. The battery is brand new, but i will put it on a charge. what could it be?

I got my car started and drove it for the first time. what a blast! 😄
 
If it an original style Bosch alternator, the external regulator will be on the passenger side inner fender near the air cleaner housing and in front of the MAP sensor.
I'd have to look, but think there should be 3 wires, power, ground, and exciter wire.
The replacements for the old Bosch voltage regulator are smaller. Dave Barton sells an adjustable regulator that will replace the original. I believe Hiperformance Auto (Eric & Ian) probably have something, maybe even a Bosch regulator.
Steve
 
Sort of off topic but if you ever want to update it, you can get a bracket to fit an 80A or 100A Denso from a 940 from TB member Canuck. Really solid upgrade and it?ll let you ditch the external regulator to clean up the wiring over on that side.

6e5LN94_d.jpg


PCzQTB2_d.jpg
 
If it an original style Bosch alternator, the external regulator will be on the passenger side inner fender near the air cleaner housing and in front of the MAP sensor.
I'd have to look, but think there should be 3 wires, power, ground, and exciter wire.
The replacements for the old Bosch voltage regulator are smaller. Dave Barton sells an adjustable regulator that will replace the original. I believe Hiperformance Auto (Eric & Ian) probably have something, maybe even a Bosch regulator.
Steve

i looked all over the passenger inner fender well. not only did i not find a voltage regulator, i didnt even see a mounting hole where one might have been.. i will look again. car is locked in at my indies garage. it wont be til monday i can look again..thx for the advice
 
Sort of off topic but if you ever want to update it, you can get a bracket to fit an 80A or 100A Denso from a 940 from TB member Canuck. Really solid upgrade and it?ll let you ditch the external regulator to clean up the wiring over on that side.

6e5LN94_d.jpg


PCzQTB2_d.jpg

thats clean. i dont have that bracket. so thats not whats going on
 
Yes, that alternator has an internal regulqator upgrade. However, you will still need to connect the large red battery wire to the + or B+ terminal. The terminal marked D+ gets the small red wire from the dash. Not sure what you do with the other connections. Maybe no connection needed with the internal regulator.

This recent thread has a good description of how the small red exciter wire works. It's the connection coming from the bulb in the dash. https://forums.tbforums.com/showthread.php?t=350999
 
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Yes, that alternator has an internal regulqator upgrade. However, you will still need to connect the large red battery wire to the + or B+ terminal. The terminal marked D+ gets the small red wire from the dash. Not sure what you do with the other connections. Maybe no connection needed with the internal regulator.

This recent thread has a good description of how the small red exciter wire works. It's the connection coming from the bulb in the dash. https://forums.tbforums.com/showthread.php?t=350999

please be the fuse, please be the fuse

alt3a.GIF
 
Good that is correct. The B+ is always hot and unfused to the battery +. So always handle with care. Key on. The D+ has 12v on it if you measure it disonnected from alternator. Measure from the wire to ground with voltmeter. But if you touch it to ground it should light the bulb.
 
I took the alternator out and had it tested by Ace Auto Electric. He said it was in perfect shape. I bought a new belt and reinstalled the alternator. Started it up and everything is fine now :wtf: Charging great. Those Mercedes alternators with the internal voltage regulators work great.
 
Can you PM me some pics of how you have that bolted up to the engine?
I'd like to see how that fits, if you have any spacers, and the alignment of your belt.
Thanks.
 
Can you PM me some pics of how you have that bolted up to the engine?
I'd like to see how that fits, if you have any spacers, and the alignment of your belt.
Thanks.

The shop is closed until monday. The large pivot bolt bolts the alternator directly to the block. It appears to be the original 19 mm bolt. No spacer at all. Not sure if the hole in the alternator was opened up, but the bolt fits perfectly. The arm for holding the alternator and keeping tension on the belt is bolted to the block (13 mm) just under the thermostat housing. Im pretty sure its in the stock location. The arm itself has a bend forward. The arm is fastened behind the ear on the alternator. The bolt goes through the alternator through the arm. The alignment of the belt is fine. There is no noticeable misalignment. And finally the plug is spliced into the cars wiring. I will try to get pictures next week. I think both volvo and mb used bosch alternators. I think they may be direct replacements
 
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