What coil?

[Mick G]

My 70 911T, basket case, sorting stuff out, well it had five ignition coils with it, blue, black, etc, just what number coil does this car take? it has a Bosch CDI factory fit, anyone got a guess, looked all over just got more confused? numbers don't make a lot of sense. Thanks Mick

[Steve@Rennsport]

Mick,

Use the black Bosch coil thats made for the CDI ignition. The blue ones are NOT CDI coils; they are designed for Kettering ignitions (inductive systems with points).

New, black Bosch coils are NLA now so the replacements are silver (always carry a spare!).

[Mick G]

Thanks Steve, now I just have to decide which of the three black coils is the correct one? one has a sticker on it that says its for TCI ignition 0221122023, one is quite a bit larger, 0221102076, and a small one 0221114006, maybe for a VW bug

[The cap'n]

The first one is for a 931 (924 Turbo), the second one is for 914s and misc old 12v VWs, and the last one is for a SWB 911 with conventional ignition (no BHKZ). Oops, I mean no Bosch "CDI" ignition system. None will work with your unmodified or upgraded Bosch ignition box. BTW, the silver coils sold as replacements for the original black units are junk, pretty much.

The Cap'n

[Flat6pac]

You want the coil, for CD power, hsmaller than a usual coil with 001 being the last digits of the part number on the bottom?

[Mick G]

Thanks for sorting out that for me, now it looks like a silver coil or two is on my list of stuff, Cap'n, how did you reference those numbers, I spent hours looking, got nowhere!. thanks for the help.

[The cap'n]

The first one on the Worldpac site, which isn't open to the public, the other 2 on Google. Took about 2 minutes. I'm NOT bragging, as I understand the erratic nature of Google searches. Sometimes you find what you want, sometimes you don't. Hint: break up the number like Bosch does it, x-xxx-xxx-xxx.

The Cap'n

[HawgRyder]

How about an MSD #8222 coil....black...high voltage...works with CDI....cost about $50.
I used one on my 69S for 5 years....never had so much as a hiccup.
Bob

[The cap'n]

There may be some misunderstanding here. As Steve said in post #2 above, the unit we commonly refer to as a coil in the Bosch CDI system is more properly termed a transformer. It's NOT a conventional coil, and substituting a conventional coil generally results in the failure of the BHKZ (the real nomenclature for the Bosch CDI unit). Loren (Systems Consulting) on this forum reconditions these units in such a way that a commonly available Bosch "Blue" coil can be installed in place of the difficult to source transformer. There may be others who do this work, but I've used Loren's services for a couple of decades and recommend him highly.

The Cap'n

[tom1394racing]

Nick

If you need the correct black Bosch CDI coil, I have several good used units. PM me to follow up if interested

[JFairman]

The epoxy filled Permatune coil is also the proper impedance for the original
Bosch ignition and the Permatune replacement ignition. It's black so it looks right and can handle the vibration and heat cycles of the motor better than the original coils.
MSD coils are the wrong impedance for the original Bosch CDI.

[304065]

Originally Posted by JFairman

The epoxy filled Permatune coil is also the proper impedance for the original
Bosch ignition and the Permatune replacement ignition. It's black so it looks right and can handle the vibration and heat cycles of the motor better than the original coils.
MSD coils are the wrong impedance for the original Bosch CDI.

Not exactly.

See my running tab of the coils here:

A lucky eBay find: NOS SWB Coil

And not recommended by Permatune:

Perma-Tune Coil Resistance Spec