Originally Posted by Sunroof (Post 8989360)

.....You are right about the silver Brazilian made coils in that two failed in my 1973.5T. I had a hard time finding any suitable replacement until a few folks mentioned the MSD Blaster coil, which I bought. Now I am experiencing intermittent "sudden shut down" that may be attributable to that coil that may be contributing heat to the CDI unit. Please correct me if I wrong here...................the CDI unit was recently rebuilt, I use a 6500 limiting rotor, standard points and this MSD Blaster coil. After a long ride, the car shuts down!!!! After a long cool down it runs again. Wrong coil? rotor?. I just ordered the original black replacement (not the silver one) from a shop in Arizona, so I hope that helps. Other have stressed to use a "non-resistor rotor".

Bob

Originally Posted by scarceller (Post 8989368)

I'm assuming this is a factory CDI ignition? In CDI the coil acts as a step up transformer and NOT a storage inductive device. I don't think the MSD coil was intended for CDI, I could be wrong but no matter I suggest you go back to the stock coil. It's possible that the MSD is simply pulling to much current from the CDI box.

Originally Posted by mreid (Post 8989373)

Any one of these, with the Pertronix being the best choice, will work better than the msd:

Ignition Coils - Universal - Canister Coil Style - 3.000 ohms Primary Resistance - Free Shipping on Orders Over $99 at Summit Racing

Originally Posted by mysocal911 (Post 8989380)

Primary resistance = 3000 ohms - NOT GOOD

Plus no other data, e.g. turns ratio.

Originally Posted by scarceller (Post 8989386)

Dave,

This shows the data for that coil
PerTronix Flame-Thrower Ignition Coils 40511 - Free Shipping on Orders Over $99 at Summit Racing
The coil shows 11mH inductance
3 ohm primary

Originally Posted by mysocal911 (Post 8989409)

Decimal point looked like a comma with all those zeros, i.e. why show three zeros
when the accuracy is probably valid to only one decimal place?

And 11mh is way too much even for an old points ignition system, i.e. not a good replacement coil!

Originally Posted by scarceller (Post 8989426)

Dave,

The stock 3.2L and 964 coil is Bosch part # 0221118322 would you happen to have the specs for this coil?

I have 3 of these black coils and 1 silver one, I've measured the following with ohm meter:
Primary - 0.6ohms
Secondary - 6000 ohms

I assume a 100:1 turn ratio?
I've also seen ref to 3.8-4.0 mH?

Do you have any formal detailed specs for the coil? or can you confirm the above info?

Thanks.

Originally Posted by mysocal911 (Post 8989469)

Check the link in post #8 as there are multiple coil values provided including the 993's.
The Bosch TCI value should be the same for both the 3.2 & 964. I haven't verified those values provided, though. Your resistive values you measured seem to agree with the Bosch TCI values
on that website.

Originally Posted by Sunroof (Post 8989360)

.....You are right about the silver Brazilian made coils in that two failed in my 1973.5T. I had a hard time finding any suitable replacement until a few folks mentioned the MSD Blaster coil, which I bought. Now I am experiencing intermittent "sudden shut down" that may be attributable to that coil that may be contributing heat to the CDI unit. Please correct me if I wrong here...................the CDI unit was recently rebuilt, I use a 6500 limiting rotor, standard points and this MSD Blaster coil. After a long ride, the car shuts down!!!! After a long cool down it runs again. Wrong coil? rotor?. I just ordered the original black replacement (not the silver one) from a shop in Arizona, so I hope that helps. Other have stressed to use a "non-resistor rotor".

Bob

Originally Posted by wwest (Post 8989519)

blah blah blah

Originally Posted by rick-l (Post 8989532)

You can't give advice till you tell me how that transformer works.SmileWavy

Originally Posted by rick-l (Post 8989527)

What does TCI stand for?

Originally Posted by scarceller (Post 8989489)

Thanks for the link that helps.

I noticed the 993 coil spec at 3.1mH vs the TCI spec at 3.6mH I know folks have used 993 coils with the 3.2L setup. This data indicates you would be likely over driving the 993 coil if used in the 3.2L?

Once again thanks.

Originally Posted by rick-l (Post 8989770)

Hey Sal what am I missing here?

4 mSec dwell ???

The green trace is the current through a 3.6 mH inductor. System voltage is 13.5
The red trace is the instantaneous power in the driver. (106 W Peak???)
The integral of the red trace is 184.36 mJ

At 900 RPM idle that works out to 8.3 Watts (22.22 mSec)
At 4000 RPM idle that works out to 37 Watts (5 mSec)

3-4 mH doesn't make that much difference.

http://forums.pelicanparts.com/uploa...1454962530.jpg