Datsun Roadster Forum-311s.org

I decided to replace my MSD coil, #8222 as it was out of spec, though not horribly. It was 5+ years old so it held up well. I went to OReilley, Autozone, Hawaii Racing, and found that the same coil, all 7 of them, were all out of spec as written on the box and stated on the Holley website, 4.5k for the secondary resistance. Secondary resistance is red lead on positive post and neg lead on coil wire tower, 20K setting on multimeter. Primary resistance is red lead on positive and black lead on negative 200 setting on meter. I checked them all out of the box and got readings of 6.0 and up. Called Holley tech support and they agreed 6.0 was reason to reject the coil, and they verified it should be 4.5k up to 5.5. I asked if they could verify a good coil then I would order from them but they said No, as did Summit and Jegs. So.. I got the red MSD Blaster 2 #8202 which did have the correct specs from PepBoys, and is the same output. It has to mount vertically, so they say. Smoother idle and a steady tach.
Anyway, point is to check the specs on electronics if possible, as they might be out, even when new.
By the way, for those with points the MSD coil 8203 has a resistor that comes with it to allow it to work correctly.
www.holley.com
Linda

I’ve been running an MSD Blaster 2 coil for almost a decade fitted horizontally, as original, with no issues. YMMV, of course.

All but $$$ multi meters are accurate to 3% which on 20k is 660 ohms and temp make a bit of difference it could be the high reading
Sure 0 oxydation on the terminals ? Best to sand off any oxydation / varnish
Multi meter s check with .015 - .007 amps
Also a good test is voltage drop
The multimeters leads go bad too, inaccurate more than you would think ,with the hair sized braids too. I've had 2 or 3 fail , cheaper to just buy a new unit

Redroadster,
These coils were “ used” out of the box. New, no oxidation. I am sure they would work, but why start out slightly defective. The guy at Hawaii Racing said they tested them before and got the stated correct spec. for previous ones they sold.
Even my used coil I am replacing had a better secondary resistance spec than the new ones I tested. Exact same model. One clerk said, “ maybe it will be OK”...... and if not, return, etc etc. No thanks.
I had the red MSD Blaster before , no issues, and this one hopefully will be good also. But I would have preferred the black, hi vibration.
I think my multimeter is good, it was checked previously but anything is possible.
Linda

Ok thought these were ones you bought new and we're going through

Was there an ignition issue that you suspected was coil related that started this sequence of events?

Yes the idle was not as smooth as I thought it could be, and has been. Been thru the timing , distributor, carbs, fuel etc. I checked the coil and it was declining, so I wanted to replace.
The more I learn the more I want to be proactive so that I am not stranded on the side of the road.I used to be like that. Keep the tires til I got a blow out, keep the battery till it would not start, etc etc. Not totally intentionally but out of ignorance in some cases. So, AAA only goes so far, prefer to work on reliability rather than just settling for any kind of running. Know what I mean?
Linda