Hello,

There are several types of coils and it is important that you use a compatible coil for your ignition system.

There are coils for points ignitions and coils for electronic ignitions.

However, some of the electronic ignition conversion kits and the 123Ignition, do allow the use of a coil for points to be used.

And in both cases, points or electronic, there are coils that use a ballast resistor, 9 volt, and coils that do not, 12 volt.

If your distributor is still using points, I suggest you use a Bosch blue coil that most air cooled VWs use, if you do not want to replace yours with an original coil assembly, either used or new.

The Bosch blue coil is a 12 volt coil and it does not need a ballast resistor.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

The 240 coil needs an external ballast resistor.

In my 51 Chevy truck I put in a ballast resistor to lower the voltage going to the original 6 volt points from the upgraded 12 volt battery. This may have been uneccessary but it worked and I never noticed any difference in performance. I had also heard that an installed resistor in a true 12 volt system would save wear and tear on the points too. There is no resistor in either of my cars that have the armored cable coil, so it's probably superfluous.

You need a 12v 3ohm coil. These were standard on all the Volvo models between the demise of the armoured cable and the end of the 140/160 series. These will be plug and play. I can't say if 240 and later ones are suitable but if you've tried one of these and it gets very warm it's probably 1.5ohm. You need a 3ohm one which will measure 3 - 3.2ohm or so. Coils are usually reliable enough to get one from a parts car. The Volvo ones are Bosch black and similar ones are on VW aircooled. Bosch blue are fine too and are considered "sports" versions, but I doubt if you'll notice any difference. Take a meter to the pick 'n pull and meter across the 2 small terminals.