Newer one has an internal regulator. Are mounting bolt holes same size?
Alternator upgrade
- Thread starter autowerks
- Start date
Chris,
Sorry about the delayed response. Unfortunately this work gets done in the margins. No the bolt holes are not the same. The newer alternator definitely has larger bolt holes.
I am figuring I will need to get the old one rebuilt and I have a shop that is willing to try. Are they going to have issues finding parts too?
Best, Greg
Sorry about the delayed response. Unfortunately this work gets done in the margins. No the bolt holes are not the same. The newer alternator definitely has larger bolt holes.
I am figuring I will need to get the old one rebuilt and I have a shop that is willing to try. Are they going to have issues finding parts too?
Best, Greg
Newer one is e12 with m10 bolt. I had mine rebuilt, don’t know what they did actually though.
I hope this helps others:
The Bosch AL655N was a great replacement for the OEM alternator on my '72 3.0cs in regards to fitment and alignment. One of the threaded bolt holes had to be drilled out to accept the slightly bigger factory mounting bolt and took less than a minute. The pulley had to be swapped over. We now have 14 volts at idle with AC Condensor Fan, Lights and Wipers on as opposed to 12 volts and the lights going dim. All with the comfort of a new "made in USA" Bosch alternator. We also used this plug for a cleaner install in regards to the D+ battery light wire.
The Bosch AL655N was a great replacement for the OEM alternator on my '72 3.0cs in regards to fitment and alignment. One of the threaded bolt holes had to be drilled out to accept the slightly bigger factory mounting bolt and took less than a minute. The pulley had to be swapped over. We now have 14 volts at idle with AC Condensor Fan, Lights and Wipers on as opposed to 12 volts and the lights going dim. All with the comfort of a new "made in USA" Bosch alternator. We also used this plug for a cleaner install in regards to the D+ battery light wire.
Mike Goble
Well-Known Member
It's basically the same as the AC Delco CS-130.
if you have to change things, i highly recommend the change to the newer style adjusting rod from the e30.
i used the 80a AL-46x with the e12 fan (12311350199) and the e12 pulley (12311362465), the bracket 12311274747, with the toothed nut 12317677914
i used the 80a AL-46x with the e12 fan (12311350199) and the e12 pulley (12311362465), the bracket 12311274747, with the toothed nut 12317677914
Honolulu
Well-Known Member
I have what I suspect is an internally regulated alternator that I may have cockroached from a '81 528i that I parted out long ago, mainly for the 5speed trans. It is visually identical to the newer version in post #20. It has a reman sticker on it, over the (unreadable) original Bosch sticker. How can I determine its original identity and amp rating?
Can someone confirm that an internally regulated alternator needs the only a wiring connections are red to D+ via the ignition switch (and battery positive) , a ground from the alternator body to engine block, and wire from alternator D+ to the voltage regulator?
Can someone confirm that an internally regulated alternator needs the only a wiring connections are red to D+ via the ignition switch (and battery positive) , a ground from the alternator body to engine block, and wire from alternator D+ to the voltage regulator?
That is correct. D comes from battery.
So here is the question of the day - i have a new internally regulated alternator and since i have my wiring harness apart to redo the lighting as well as replace the red wire between the battery + alternator (significantly chewed up), now i know why i kept having electrical issues in the past ... and i am doing some suggested edits suggested from @sfdon ... i realized that my car still has the original wiring harness for the external voltage regulator. so i was going to keep the D+ blue wire in place, as it eventually runs to the program tester plug. i am probably going to leave the external voltage regulator off of the car, so i will probably run a new blue wire from the D+ alternator straight to the program tester connector ... so it continues the circuit to the red (battery charge) light on the dash gauge. does that make sense to everybody? if i do that, i could just eliminate that plug out of the harness and eliminate the black + brown wire between the alternator / voltage regulator harness ... i will add a ground wire between the alternator and the body.
now for the next question - with a new external voltage gauge, what is the best location to connect the new gauge to? might as well run the new wire within the harness while its mostly open.
I just tapped into a +12v wire at the fuse box so it is fused.
that sounds like a reasonably good idea ... and it doesn't require running thru the harness.
Looking at upgrading the alternator while changing the fan and viscous clutch, looks like a few options here. I reached out the BNRParts on Ebay, those tend to run about $500 vs the Bosch for $112 or a AC Delco for $120 or so. Any reason to spend the money on the BNR? Seems like folks have been happy with the Bosch or Delco. Also sounds like I'll have to fiddle a bit with getting screws to work depending on which one I choose but that seems easily surmountable.
New Bosch for it's price is an absolute no brainer.
You aware that offsets differ on different alternator pulleys?
Rebuild the one you have, as Don mentions you might need to swap the pulley if you buy a new alt. And it mounts with an m10 bolt, later BMWs are 8mm.
Hmmm. So let me dive a bit deeper into this and perhaps end up drowning...
I was already planning to upgrade the water pump (ordered) along with the new fan (9-blade black in lieu of my 5-blade red). I am currently sourcing the 130mm pulley that is often recommended for this changeover. I think that this represents the "Gen3" in the @sfdon hierarchy. Since the alternator seemed to be in not-great condition and others had recommended that higher amperage might be better, that was what motivated this quest. Based on previous threads, the Bosch seemed to be basically plug-and-play with only slight modification, but perhaps I'm misreading that?
So the questions:
1. Seems to make sense to do both alternator and water pump/fan at the same time. Correct? Anything else that I should be doing at the same time?
2. Since I'm going to need to remove the radiator and I don't see that it has ever seen any service in the records that I have, I also planned on bringing it for cleaning/recoring. Agree?
3. With regards to the offset, I assume that you are referring to the front/back offset, which of course is critical to ensure that the belt travels along a linear path without twisting. I don't have AC or power steering so should only have this single belt, I would also assume that there is a way to correct any disparity in the offset?
Thanks in advance. All of my previous work in this arena has been replacing like with like in my E39, not with upgrading to parts from different engines/time periods.
I was already planning to upgrade the water pump (ordered) along with the new fan (9-blade black in lieu of my 5-blade red). I am currently sourcing the 130mm pulley that is often recommended for this changeover. I think that this represents the "Gen3" in the @sfdon hierarchy. Since the alternator seemed to be in not-great condition and others had recommended that higher amperage might be better, that was what motivated this quest. Based on previous threads, the Bosch seemed to be basically plug-and-play with only slight modification, but perhaps I'm misreading that?
So the questions:
1. Seems to make sense to do both alternator and water pump/fan at the same time. Correct? Anything else that I should be doing at the same time?
2. Since I'm going to need to remove the radiator and I don't see that it has ever seen any service in the records that I have, I also planned on bringing it for cleaning/recoring. Agree?
3. With regards to the offset, I assume that you are referring to the front/back offset, which of course is critical to ensure that the belt travels along a linear path without twisting. I don't have AC or power steering so should only have this single belt, I would also assume that there is a way to correct any disparity in the offset?
Thanks in advance. All of my previous work in this arena has been replacing like with like in my E39, not with upgrading to parts from different engines/time periods.
Did you ask around first for a radiator rebuild?
Let us know what you find.
Let us know what you find.
Seattle Radiator Works can do the radiator rebuild, they estimate about $500-600 which sounds in line with what people have noted in previous threads.
Called a local alternator rebuilder (Romaine Electric, recommended), their rate is $125/hr+parts. When I asked about rebuild vs purchase new, his basic answer was "often cheaper to just buy a new one because we are typically at least 1-2 hours of labor". So, the Bosch at $112 plus any cost of an alternate pulley is likely cheaper and I would suppose has the advantage of higher amperage...
Called a local alternator rebuilder (Romaine Electric, recommended), their rate is $125/hr+parts. When I asked about rebuild vs purchase new, his basic answer was "often cheaper to just buy a new one because we are typically at least 1-2 hours of labor". So, the Bosch at $112 plus any cost of an alternate pulley is likely cheaper and I would suppose has the advantage of higher amperage...
I think one day we need a cage match between @HB Chris, @sfdon and the other well-known members/moderators on here 
You all have such knowledgeable but sometime conflicting opinions...
My inclination given cost and willingness to not have "original" items is to go for the Bosch. @eb88 can you provide info in that case on the pulley used to address Don's concern? Were you able to use the same pulley without issue?
You all have such knowledgeable but sometime conflicting opinions...My inclination given cost and willingness to not have "original" items is to go for the Bosch. @eb88 can you provide info in that case on the pulley used to address Don's concern? Were you able to use the same pulley without issue?