120 and or 140 Series Alternator Replacement/Upgrade...anything common that can be used?

jackafricaricho @jackafrica Hobart Tasmania
edited September 2019 in General

Is there a common type of inexpensive alternator that can be used on a B20?

Preferably internal regulator. Don't mind spacing or machining of mounts.

Going from the generator it'll be like night and day 😊

Perhaps something initially fitted to a Volvo? Nothing over the top, 50 amps or a little more.

240 series with internal reg, how many amps?


  • The fuel injected B20E had a 55A external reg unit standard.

  • holden vn easy mod to drill out mounting hole

  • jackafricaricho @jackafrica Hobart Tasmania
    edited September 2019

    Thanks, it’s a bulky unit.

    Looking for clearance with extractors.

    Will see if I can look at one. Wondered about the pulley change...do you buy the V8 version with the V pulley rather than serpentine?

    VN-VR pretty thin on the ground now!

    Thanks again.

  • jackafricaricho @jackafrica Hobart Tasmania
    edited September 2019

    I'll call the US in the morning and see if they'll share the info, provided they remember what it is! The article is quite old. The unit looks sufficiently compact.

    Thanks mate.

    I'm surprised no-one in this country or on this forum hasn't found an alternative locally.

    UPDATE: The alternator in the USA is approximately $400Aud shipped to here. $ 170US plus shipping of $80US, and insurance $10US.

  • You say B20 and mention extractor clearance. Are you running the alternator on the drivers side?

    I assume you know this, though if there are two large threaded holes on the passenger side of the timing case you can put an alternator there, as big as you like. B20s often have this. If this is an option for you, call Voldat or Berrys and get an alternator and the lower and top brackets, bolts, new belt, re run wires, done.

    If you are drivers side, you probably have the iPd or Skandix aftermarket mount onto the block. My B18 will foul anything that is not an SEK on the chassis or steering box (in an 1800S) as an SEK Marchal alternator is smaller than a Bosch. I went with the above mentioned 55A SEK from a late B20 and found a solid state external reg that I mounted to the rear of the alternator. It is absolutely an external reg btw. Pretty sure the same unit was on the old 140 before it was sold. I know I bought two regs back then. The trouble will be finding a 55A alternator. They are distinctive as they have a large red heat sync on the back, the 35A units from earlier have a much smaller heat sync.

    I can take a pic in a day or so when next at the workshop if you like. The reg was a bugger to find too, took literally 10 or 15 night time hours to find a unit that would work. I think it came from Hungary, will look for details if you like. And it works a treat.

    Depending on the chassis, the VN mod may not fit, i sold a VN modded alternator a few weeks back to a guy doing exactly what you are planning for a 160. Maybe scroll down and have a search for that as a reference.

    There is also the later B20 Bosch alternator. The simplest of the lot. Factory for later engines, it was on the passenger side, it is bigger than the SEV Marchal. Someone (Angus maybe) had a few old engines, he may have some old alternators to test clearance with. Just check the alternator is clear of the steering box and chassis. I do recall an after market mount that used the fuel pump bolt holes to put an alternator on the passenger side, though it looked very flimsey.

    Also check your wiring, I found a butchered up Bosch alternator on my 1800 rated at 65 amps and the factory 40A cable. It is now a more appropriate alternator and solid wiring (for the alternator anyway, the rest is yet to be cleaned up).

  • jackafricaricho @jackafrica Hobart Tasmania
    edited September 2019

    Thanks ROLL DMC for sharing the information, that's what I needed.

    Looked at the block and sure enough there are the two mounting points on the left side for making a bracket. Considered the VN-VR Commodore V8 unit mounted on the left side, preferred the RH mount.

    Call me contrary.

    Found both a 45amp and 50 amp compact unit, inspired by the linked story Volvodriverman provided.

    Both marketed as OEX by Ashdown-Ingram, they are Denso style replacements for Daihatsu Charade (DXA416) and Toyota Forklift (DXA418).

    Both internal reg, three wire alternators. Large post to battery, one to the + on the ignition coil, the other to the warning light.

    Length or depth is only 140mm from pulley face to rear of unit, diameter is 105mm and length between the mounting ears is 156mm, very similar to the old generator. Weighs in at 3.6kg, much less than the genny.

    My application doesn't call for big output.

    Clearance is no issue using the B20 lower mount, which is 7/16" UNC. Plenty of meat to drill out the body.

    Next will be to see how it could be adapted to the original generator mount for application to a B18.

    Thanks again to those who've contributed positively.

  • SpacSpac @Spac Canberra-ish.

    I have fitted the alternators from second generation Mazda RX-7s (85-91) to both B20 and B30 motors.

    I can’t remember the process, but it was straightforward.

    They were plentiful and dirt cheap at the time, but I would check the availability now before choosing to use one now. They are a very good alternator though - good capacity (85A or 100A, depending on which one you got), reliable and pretty good packaging.

  • If you are actually replacing a generator (thought they were all binned in the '80s) then you need the mentioned aftermarket bracket for the drivers side. if you go passenger side you need the factory mounts and can go a factory looking arrangement. i always thought the passenger would look better as it looked more balanced in the engine bay.

  • jackafricaricho @jackafrica Hobart Tasmania
    edited October 2019

    Generator, binned? No way. One (was) on the car and a spare....anyone want to buy one?

    The wiring has been putzed with by a clueless clown, but the genny is still hanging in.

    Yep, complete with original three point rubber mounted bracket, straight onto the B20 block. Fitted after the original B18 was binned (by the PO).

    I sorta like the clear left or passengers side. Yeah the drivers side is real busy, eh!

    So what I've done is.....

    given up trying to upload pics in the correct orientation.

    Fitted a DXA416 to the RH side of a stuffed B20 block. Machined one, push fit, sleeved spacer for the lower mount, with a 7/16" x 2 1/2'" UNC bolt.

    Top mount has a 29mm spacer drilled to 8.0mm for the 8mm x 1.25 thread in the alternator. Then very carefully filed the hex of a suitable bolt to 7/16' head (don't want any spanner confusion), machined an old Citroen washer.

    Will probably require a smaller belt, dunno until I get the engine back from engine machinists and assemble.

    Wiring to come, it's a simple 3 wire alternator.

Sign In or Register to comment.