CDI/coil confusion...please help my poor SC...

[konish]

After some heat related ignition trouble, I really suspect my Perma Tune is about to die (car died 2X yesterday) and barely made it home today. Did a BUNCH of searches here, and am more confused than ever. Read through Loren's site, and read a quite a few opinions about stock, Perma Tune, MSD, Crane etc. Here is where I'm at so far:
(Car is an 83 SC)
1. I have a good, used Bosch CDI box on the way.

2. I don't want a bad coil potenitally destroying a good box so I'd like to replace it.

3. I've read many references to the Bosch Blue Coil, however mine is black and I suspect the original coil that came with the car.

3. I can't find the procedure to test my black coil 0 221 121 001(already did multiple searches under CD coil testing). However I did find some primary and secondary resistance numbers....just need to know how to test it.

4. My car is stock and since I already picked up a used box I'd like to stick with the Bosch...although I have looked into the MSD (part of the reason I'm so confused).

Questions:
1. PP sells a coil A-602-502-00 for $180, but the searches I have done suggest that I can buy a Bosch blue coil for like $60? What the heck is the part that PP has that could cause the price differential?

2. I think Loren states that almost any coil can be used with the stock, Bosch box..therefore can I run over to the speed shop and buy an Accel (et al) coil and be safe running the stock box?

I really suspect it's the Perma Tune, but I also don't want a potentially bad coil from destroying the new (used) CDI box.
Any thoughts or suggestions would be MOST appreciated.

R/
Dustin

[rlane]

i WENT THRU THE SAME THING.....stay with the Bosch box and I believe you need the black coil. There is a test procedure either in the Haynes manual or in the Porsche shop manual, if you can't find it I will try and check it out tomorrow. You can use the blue coil with the MSD but I have heard NOT to use it with Ptune or the Bosch box. Not sure about an aftermarket coil with Ptune or Bosch but I went with MSD because almost every speed shop has all the components for that Saturday track failure....Loren would certainly be the trusted expert on this.

[Early_S_Man]

Dustin,

Unless your original coil is leaking, I wouldn't worry about it.

The test values are 0.4 - 0.6 Ohms for the primary, from terminal #1 [ground] to terminal 'A'.

The secondary should be 650 - 790 Ohms, from terminal #1 [ground] to #4 output tower center contact.

Most multimeters aren't accurate below one Ohm, so don't worry much about the primary value. The secondary is what can short out if flashover occurs internally, but overheating occurs quickly and the leaking results ... if a problem has occured with the secondary winding.

Have you checkec the green cable coming out of the distributor for cracking? The definitive test is to pull the 6-pin connector from the bottom of the CDI unit and check for 600 Ohm reading from the pickup coil in the distributor, then check with multimeter set to AC Volts, and check for 1 - 2 Volt signal during engine cranking.

The following diagram may help:

[Lorenfb]

As has been said, continue to use the original small Bosch coil that came with the car.
They are very reliable. Don't waste your money and have to deal with a potential
problem with a new coil (silver Bosch coils are not reliable).

[konish]

Thanks everyone, just confirmed what I thought I was reading. I will say I did expect both Warren and Loren to respond...thanks fellas. I will say (much to the chagrin of Loren) that I also got a screamin deal on an MSD 6AL w/ a high vibration Blaster coil and rev limiter pills for $250 shipped. My reason wasn't really for the performance gain (arguable) but for the sheer convenience of driving to any local speed shop for parts/service at a reasonable price. In the long run, I'll leave my wiring stock and switch back if necessary.

R/
Dustin

[konish]

Warren,
The coil tested good on both primary and secondary circuits...I was impressed with my multi meter...it actually showed less than 1 ohm of resistance. Also, thanks for the diagram, at least it confirms my Bentley on the dist output wire at pins 7 and 31D. Now, if they only drew the connector as it exists in the car I could actually find where pins 7 and 31D are located in the 6 pin connector. You'd like to think it would be more intuitive and maybe I'm missing something but which of the six are the top row and which are the bottom...I guess I'll just have to peel bach the rubber boot to actually id the colors. My wire from the dist. is brown, book says NCA (no color assigned?)...not a big deal I'm guessing as there are some wire color combos that are off a bit throughout the manual....

R/
Dustin

[Early_S_Man]

[konish]

Dang, Warren...you are awesome! Thanks!

R/
Dustin

[konish]

Update II,
Okay...my car's plug is exactly opposite from what you posted above, in fact I even looked under the big rubber boot and confirmed the colors...opposite. Now, I wonder...if you buy a used box, how can you ensure the pins are in the right place for a specific car's wiring? In other words, if the box itself does not have the pins identified, I don't see how you'd ever know that the pins are appropriately arranged...?

R/
Dustin

[Early_S_Man]

Dustin,

I believe we are dealing with a discrepancy in the diagram ... and inconsistency in some factory diagrams, i.e., some show the cable connector end looking at it when disconnected, and others (like this 6-pin CDI) show the box looking at the pins.

Back to the distributor signal cable for a moment ... they are all green when they leave the factory, but if yours has turned brown like the one in the pic below ... then I strongly suggest replacing it, it is only abot $30 from Pelican!

[A Quiet Boom]

konish,

your box will be there tommorrow and it has the pins identified on it like Warren's photo.

[konish]

Chris,
Thanks a million! Hate having a disabled car....

R/
Dustin