I know I need either a new alternator or a new voltage regulator or both in my 1972 220D.
When I'm playing tapes in the car, the tape speed will vary with the engine RPM.
This morning was the last straw. I had to jump the car and it's got a battery that is only a month old. Right now the alternator is spiking up to just under 13v when I hit the throttle and watch a handheld voltmeter, so I'm pretty sure it's time for it to go.

So, in a week I'm switching my sealed beams to H4 bulbs and adding a pair of factory fog lamps. I don't have air conditioning so there's no draw there.

The stock alternator is supposed to supply 35 amps and I'm wondering what upgrade options I have? Can I just stick in a 55amp alternator from a 300D and call it a day?

I still have the external voltage regulator up on the passenger side of the engine compartment. If I upgrade the alternator to a higher output one, do I need to upgrade the voltage regulator?

Considering this is a 220D, what alternator options do I have past 55amps?

Thanks all!

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

can you post a picture of your alternator?

if it's got an external regulator, none of the 123/126 etc alternators will work unmodified. however, you may be able to bypass the regulator, and wire it as the 123 is wired.
maybe you can pull the entire harness from a 123 charging circuit, and install it all...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Mine is this type


Mine has the condenser on the back side of the alternator and a harness attached to the voltage regulator on the wheel well.
Will a properly operating 35amp unit such as this run my (soon to be upgraded) H4 headlights, fog lamps and all the rest of the things in the car? If so, I have no problem just replacing it. But I'd rather have the extra power if there is a way to get it done.

Thanks!
Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

So, I thought I'd give an hour or two towards cleaning the electrical system before I jumped on getting another alternator.

I disconnected the battery first.

I started my cleaning at the alternator and removed the strap and cleaned the ground contacts. There was a decent amount of corrosion and I wound up using a Dremel tool to grind it off and get a good bare metal contact.

Then I pulled off the condenser wire, cleaned those contacts and put it back together.

I moved to the three prong plug and cleaned it out with a small round file.

Then the big part came. The ground contact on the voltage regulator was covered in corrosion so I hit that, the body where it made contact and the voltage regulator bracket.

I cleaned out the plug with a folded piece of sandpaper and the male contacts with a small file.

I had the voltage regulator off and noticed it had a strip of electrical tape around the base. I removed the tape and took the top off and saw the contents.
The capacitor inside was fine and the contacts that the electromagnet drives were dirty. I used the sandpaper between all the contacts and put it back together. I used a strip of metallic chrome tape to join the cover to the base of the voltage regulator.

I bolted it back to the body and made sure all the contact points had a good bare metal surface for contact.

Reconnected the battery and fired the car up then took a drive.

I turned on my Becker tape deck and the RPM of the car no longer had an effect on the sound of the tape! So I dove to Autozone where I had already ordered an alternator and had them test my system.

At idle it was charging fine. At idle with the lights on it was still charging fine. Revving up it was great with and without a load. So it turns out the only problem was all the corroded and dirty contacts in the charging circuit.

No alternator needed! Now on to flushing the cooling system, sticking in the new heater blower (with new brushes) and replacing the radiator with a newly flow/pressure tested and painted one I pulled from the junkyard last week.

One day I may change the alternator for a higher amp unit but when I do, I'll rewire the engine. This is fine for now.

Thanks all!

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

looking at those pics, no... a 123 or newer alternator will not fit.
it MAY be possible to remove the front cover, and swap it onto a 123 alternator, but I do not know.
I'd not try to run H4's with a 35A alternator...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

How about sealed beams and the factory correct fog lamps? These cars shipped with them and the same alternator (as far as I can tell) so in theory, they should run fine, yes?
I've wanted to switch to H4 bulbs for my main headlights just for better light output but if they are going to put too much strain on the charging system, I'll keep the sealed beams.

How did the Euro cars get around this with higher output bulbs and fog lamps? Were they spec'd with higher amp alternators?

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

they must have. H4's will pull 40 amps I think...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Wow. Well, I'll be upgrading the alternator eventually, I guess. I just need to find a sure-fire way of getting it done without too much surgery or a complete re-wire.

Phil Forrest

__________________
1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson

it looks like Im wrong.
H4's pull about 5 amps each... so you should be fine with the 35amp alt, but be sure you run the power through a relay so there is no drop in voltage to them. (low volts, low light output, and lower amp draw, high volts, high light output, and high ampdraw... but shorter bulb life...)

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

depends on the wattage of the bulbs... I'm finding the H4's are available in 60, 55, and 100/80 watts... the 100/80 watt jobbies will pull around 16 amps as a pair at 13v still within the range of ability of a 35amp alternator, but it'll seriously cut down on what else can run... like heat blowers, and radios...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!