Why not just get a stock alternator rewound for more amps?

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1982 300D Turbodiesel, daily driver. Mods so far: Fram 8038 paper filter, 4 brake light mod, Gen II w126 (front) rotors/calipers, boost turned up to 12lbs, non-egr manifolds, water/methanol injection, 4-speed manual
1980 300SD Turbodiesel, project car, nearly ready to hit the street

1974 240D, New paint

I did this on several of my Mercs both NA and turbo chagred .

It was so long ago that I don't recall the details but you're fighting your self by trying with the belts in place .


As I mentioned earlier , the higher out put alternator is still worthless until you get a BOSCH branded voltage regulator , then even the weeny 55 Ampere original ones are just fine .

HUGO and other off brand voltage regulators never raise the voltage high enough to get full charging , especially around town where 99 % of all driving occurs .

Try installing it with the bent adjuster fixed and no belts then see .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Same, my SD and 560 both have this alternator (and a few E23 BMW now)...I encountered no install issues. You can actually run more than one thing and have the car charge at idle.



I have never had good luck with idle power with small case alternators 'rewound' for higher maximum amperage. A bigger case just works better all around.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Generally...re-winding for more peak output will reduce the low RPM output in most cases.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

Thanks for All the suggestions so far, putting the bracket on the alt was the bit I had forgotten. However, I am still having trouble getting the top bolt on. The 'dent' in the top Bracket needs to be deeper, I'm still hitting the water outlet. I am considering notching it out so that it will clear more easily.

I do remember some difficulty with the top bolt. It lined up I just had to jimmy it enough to get the bolt through.

Is this on a 123 or 126?

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

83 300td, w123.

I was hoping I didn't have to get another set of belts, I bought MB belts which aren't serated on the narrow side of the belt.

Any down side to notching-out the bracket a bit? I am not wanting to cut out the whole 'dent', but instead a bit about 1.5-2" in from the edge. I'll search.

Get the alternator mounted first, then worry about the belts. There are 2 long mounting bolts. Put one of them on first (do not tighten), then use a pry bar to line up the second bolt.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I've tried that, as I said I keep hitting the water outlet with the bracket.

Without seeing it in person or good pics, it's hard to help. Best I can suggest is compare the old alt and the new and determine why the new alt is interfering and use your best judgement to come up with a solution.

Is there a bushing (on one of the mount bolt holes) that gets pushed in that needs to be pushed back out (with a bolt+ washers + nut)? On a VW with Bosch alt I need to do that but I do not remember if that's the same in a W123.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

A good thought; I owned for one but did not see any. I will look again.

As malleable as these stupid top mounts are, I wonder if mine has distorted in such a way that it won't mount properly... Just thinking out loud here... I don't think so, But I dont understand why I am having so much trouble.

The reason the top bracket is hitting the water outlet is because the eye that accept the top bolt on the alternator has moved with this newer alternator. In other words, the diameter of the alternator as you look at the pulley end of it has increased, pushing the bolt hole further away from where the pulley sits. As I try to align the top mount with the the hole in the alt and the mount on the engine, the alternator and water outlet are getting in my way...

Possible solution (without getting other belts); cut out the bent portion of the top mount so that the water outlet can go deeper, allowing the bolt to line up more easily. If I do this, I will reinforce it from underneath that that it does not flex... Despite how it might look in the pics, the mount is very straight, other than the part that holds that captive nut.

Here is the modified bracket to clear the outlet...

I figure the reason why I have had trouble and others have not is because I am using MB belts, which don't have the corrugation on the narrow side of the belt. If I had, I would probably not have any trouble. Thing is, I Wanted to use these belts since there was more meat there, so...

Good to see you're getting a handle on it .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better