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Discussion Starter · #1 ·
Probably a stupid question but will an electronic distributor with an ICU work on a carburated B-20 or is a unit like that for fuel injection only?
 

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If you're talking about the distributor from a Djetronic fuel injected B20, then yes. It will work on a carbureted B20.

Best,

Cameron
SwedishRelics
Portland OR
 

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100%. Points are one of the most unreliable pieces of the ignition.
 

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The '75 breakerless distributor makes for a nice upgrade that's pretty close to maintenance-free. The advance curve isn't dialed in for your engine, but unless you're running something fairly modified, it won't matter much at all.

If it's affordable, I'd say go for it.

Cameron
SwedishRelics
Portland OR
 

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Discussion Starter · #7 ·
The '75 breakerless distributor makes for a nice upgrade that's pretty close to maintenance-free. The advance curve isn't dialed in for your engine, but unless you're running something fairly modified, it won't matter much at all.

If it's affordable, I'd say go for it.

Cameron
SwedishRelics
Portland OR
Okay. Stock engine, as far as I know. Is it possible to reprogram the computer?
 

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There's no computer in the '75 breakerless module. It's basically a capacitive discharge unit to fire the coil. The distributor has a mechanical advance.
 

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Discussion Starter · #9 ·
There's no computer in the '75 breakerless module. It's basically a capacitive discharge unit to fire the coil. The distributor has a mechanical advance.
You wouldn't happen to have a wiring diagram for this, would you?
 

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I don't think there is much to it, one wire to +12V, two wires to the coil and one to the distributor. Or is it two to the distrib. I might have a chance to look at mine soon, it's on my '74 in the barn (transplanted to it years ago).

Or: https://www.google.com/#q=1975+volvo+wiring+diagram
 

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The '75 breakerless distributor makes for a nice upgrade that's pretty close to maintenance-free. The advance curve isn't dialed in for your engine, but unless you're running something fairly modified, it won't matter much at all.

If it's affordable, I'd say go for it.

Cameron
SwedishRelics
Portland OR
Cameron... I have a complete '75 distributor with the black box that never got installed on my 122 before I sold. Would it make sense to install this on my '74 142?
 

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There's no computer in the '75 breakerless module. It's basically a capacitive discharge unit to fire the coil. The distributor has a mechanical advance.
CDI or transistor switched?

CDI is / was pretty common on 2 strokes because the exceedingly fast rise time on the spark current made them more resistant to misfire caused by oil fouling on the plug insulator. However, not so common on 4 strokes because the spark duration tends to be short and oil fouling resistance is not a big feature. Transistor switching is common on 4 strokes because it is simpler and more robust (a lot less parts). Pertronix modules are transistor switched units.

If the early Volvo units truly are CDI units you might want to give them a pass.
 

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CDI or transistor switched?

CDI is / was pretty common on 2 strokes because the exceedingly fast rise time on the spark current made them more resistant to misfire caused by oil fouling on the plug insulator. However, not so common on 4 strokes because the spark duration tends to be short and oil fouling resistance is not a big feature. Transistor switching is common on 4 strokes because it is simpler and more robust (a lot less parts). Pertronix modules are transistor switched units.

If the early Volvo units truly are CDI units you might want to give them a pass.
Actually I'm not certain of the technology in the module. But it's not physically like the Pertronix. There is a 4-lobe impulse sensor in the distributor, and a paperback-book-sized sealed control module on the firewall.
 
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