Hi. A previous warning: my answers are limited to my personal experience on Peru.

>Anyone ever replaced the original one wire coil on the 122?

Usually the original coil work ok. But, on my car, I change it due the coil was damaged by the previous owner (bakelite central contact was broken).

>Does this coil weaken with age?

Any coil weaken with age. But usually coils goes bad after many many years of continous use.

A easy check using a old trick (please, try it only in original ignitions, dont try it if you have your ignition upgraded to electronics - too much power involved): disconnect the ignition wire (the one coming from the coil) from the distributor. Locate it a one centimeter (3/8") over the engine block (please, hand the wire from the plastic cover, not the metalic borne and dont touch the engine block) and start the engine. A blueish/whithe spark will be jump between the metalic borne of the wire and the block. If the spark is yellow, replacing the coil is advisable (due low power delivery).


>Is there an advantage to going with a newer, "hotter" coil,

Yes and not. The original 50's coil is a bit unpowered (12-14 Kvolts) like any coil of that era (before muscle cars) in comparision with later coils, but it will be ok for a brand new original ignition. Of course, after 30 or more years of use the original ignition need some help to overcome wear.

I use previously a bosch Red Coil (28 Kvolts, need resistor/ballast - i set it over the fan cover), but it goes too hot after long drivings (2-3 hrs).



A detail: on the photo the additional wire on the (-) terminal on the coil goes to a tachometer.

After it, I change to the blue one (26 Kvolts, available on vw stores). It has a internal ballast (like the original). It work as a charm with my ignition.



>I don`t relish the thought of cutting into the armored cable going to the ignition switch.

I exchange the original ignition switch with a "universal" ignition switch (available on any auto store). Electrical terminals on the switch are like the original, plus one more terminal on replace of the armored cable. I wire a 12 awg from that terminal to the (+) terminal on the bosch coil.

Also, i set the new coil on place of the old one using a metalic adapter of my own design (see previuos photos), but other more usual options are available (like the one on: http://groups.msn.com/ClubVolvodelPeru/volvo122sdekarl.msnw?action=ShowPhoto&PhotoID=262 . This owner made a full ignition system refurbish including a electronic ignitor on the distributor to fit the 48K volts coil).

After my experience, I believe than cutting the armored cable is a more easy option than changing switches.

>Thoughts and experiences?

If you adquire a Bosch blue coil, check the source: it will be come from Germany (scarse now) or Brazil. Blue coils from other countries could be falsified (details on http://www.ratwell.com/technical/BlueCoil.html ).

More powerfull coils are available (48 kvolts or more), but that high punch could be too much to other components of the ignition (like distributor cap or rotor).

Also, is a good idea to change the ignition wires every four years. Amazons work best with metalic wires. I use a silicone covered ones (for vw beetle, I adapt it, some cut needed) with head resistors (it cut radial interference - a problem with metalic wires). I know in US you have Magnecor and Bosch wires sets available customizated to Amazons.

If you distributor has a booble central axis (some lateral play), suggest put in mind a upgrade from points to a electronic ignition (like perlux, crane or ignitor).

On my case my distributor was ok, but due the the quality of gasoline available here, I put a MSD 5 ignition "amplifier" between distributor and coil (under 3k rpm it send some sucessive sparks on place a one and a powerfull one after that rpm, it guarantee a full cylinder ignition, also optimize the dwell angle). Now my amazon run on any 95 or 97 RON local gasoline and on idle it sound like a black singer sewing machine.


Happy volving,
Joaquin / Rojo 121 / Lima, Peru