MSD Ignition coil dependencies?

[francesconyc]

I read on this forum about people switching to the MSD high vibration coil.
What i don’t understand is if can be replaced as is on a Porsche 911SC or do i need anything else?

I read about rotor (no idea which part is it) or in the instructions they mention a part that im not sure what it is

Any recommendation is welcome!
Thanks

[smadsen]

I replaced the original Bosch coil on my '82 SC, which was leaking, about 12 years & 100,000 miles ago with the MSD off road coil. It wires up just like the stock coil. I've seen no difference in the condition of the distributor cap or rotor. Be aware there is a difference in the diameter of the cable hole between the MSD coil and the stock Bosch distributor cap that requires the 7mm wire (I think) be slightly modified so it doesn't "rattle" in the MSD 8mm receptacle. If it's "loose," it can arc in the boot and cause a problem.

[silverlock]

I proactively swapped the OE Bosch coil with an MSD high vibration coil (P/N MSD-PN8222) on my SC with no issues — although I have updated Clewett wires. Zero changes. Runs fine. No evidence of arcing.

I keep the OE in my spares kit in the frunk.

[Schulisco]

More detailed info on ignition coils on CDI (=HKZ in german) ignitions especially on Porsches...

https://www-911--hkz-de.translate.goog/Zuendspulen.htm?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp

You can replace the original coil with the MSD8222 with no issues, technically it creates a three times longer spark (100us) than the original (27us). But this has almost no effect, neither positive nor negative.

The high vibration resistant coils as the 8222 are epoxy filled instead the others oil filled. Therefore it's vibration resistant and can be mounted upright as on aircooled 911's.

I read about rotor (no idea which part is it) or in the instructions they mention a part that im not sure what it is

The rotor is within the distributor distributing the spark to every spark plug in time. It belongs to those ignition maintenance parts to be inspected regurlarly like the plugs, the rotor cap and the ignition cables and is required replaced occasionally. I highly recommend to introduce yourself in the technique of your 911 by reading books or even watching some of the fabolous videos from Klassik ATS, e.g. like these:
Porsche 15K Service Part One
Porsche 15K Service Part Two
There are plenty of very helpful videos on this channel, esp. for 911 owners.

Also good:
https://www.youtube.com/watch?v=dS7jtsx-t_4

Thomas

[francesconyc]

ok, so it seems in dont need the 0.8ohm resistor mentioned in the instructions inside the coil package

[Schulisco]

Originally Posted by francesconyc

ok, so it seems in dont need the 0.8ohm resistor mentioned in the instructions inside the coil package

Correct. If you want to use it on a CDI.
The CDI uses the coil as a transformer. The spark energy is stored in the capacitor. On a common transistorized ignition the coil is used as storage for the spark energy. That's the main difference between them.

Thomas

[mysocal911]

Originally Posted by Schulisco

Correct. If you want to use it on a CDI.
The CDI uses the coil as a transformer. The spark energy is stored in the capacitor. On a common transistorized ignition the coil is used as storage for the spark energy. That's the main difference between them.

Thomas

Right, where the primary resistance of the coil becomes important so the switching device, e.g. the transistor, is not damaged and the necessary energy is developed for the spark.

[francesconyc]

got it thanks!