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B20 Alternator Conversion?

I recently bought a '67 Volvo 122S. It came with a reconstructed B20 engine. The engine still has a generator on it. I've heard that it is possible to install an alternator. I was wondering if you knew what all I would need? I know I need a voltage regulator, but is that all? Also, what kind of alternator would you recommend I install?
Russell Hammack

Phil says: First off, find out if you really have a B20 rather than the B18 that is original to your year Volvo. Look for the cast label at the extreme top rear of the distributor side of the block to be sure.

The reason I ask is because no B20 was originally equipped with a generator (OK, readers, if I'm wrong, let me know)...

Protracted discussion between Phil and David happens here. There is much lifting of hoods, looking in books and noting of engine serial numbers. The only thing concluded is that there is a lot of variation between individual cars and engines, based on factors including the state of Odin's digestion on any given day.

...and the mounting boss in the block is different between generator and alternator-equipped engines. If your block has the alternator mounting "ear," you should be able to use a Bosch or Marchal (Motorola) alternator from a 140-series, and use the voltage regulator and regulator wiring harness from the donor car. Units from yet newer Volvos are physically larger and may be difficult to install comfortably.

If your block has the three holes for mounting a generator bracket, I recommend the Swedish Embassy Delco conversion kit (see Archive article), which is a "one-wire" system, requiring no external regulator, and producing a lot more juice than the Bosch / Marchal units.

Jim says: A couple of notes:

  1. Use a 55 amp alternator from a fuel injected car, not a 35 amp.
  2. The regulators for the Bosch and SEV Marchal alternators aren't interchangeable, and the generic over-the-counter replacements only work with the Bosch. Quite a few rebuilders won't touch the SEV alternator because of reliability problems; though I have one on my 544, I got a lifetime warranty and went through several before finding a good one.

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