MSD guys - which plugs?

Scott S · Scott S's Garage

Hi All -
One of the things on my winter list is the usual tune up stuff. I will be replacing my plugs in all of this. I am using the MSD 6A with a compufire in the dizzy. Any recomendations on plugs? I am currently using non platinum Bosch plugs with the MSD recommended HUGE gap.
Thanks for any insight/help!
Scott S

jabb · 01-06-2003, 03:42 PM

I use NGK I think BP7ES those are on a 6.... Do not go to big on the gap you can get High speed misses. I think I am gapped at about 42.000.

gint · 01-06-2003, 07:40 PM

Interesting. I just installed an MSD 6AL on my /6 a month or so ago with new NGK's. After a few hundred miles I've developed a high speed miss. 2nd and 3rd gear mostly when I'm really jammin on it all the way to redline on the back roads. I initially gapped to .045 Think I should back off to .040?

John Rogers · 01-06-2003, 09:07 PM

Snap-on sells a really neat secondary voltage measuring tool that reads the voltage at the plug by inductance. You could try to find a shop that has one and do a check of the plug voltage at high RPM to see if it breaking down. MSD also has a tester that you can use to test the output of the "box" to see what it is doing at all RPM ranges. I have used these several times to track down the fact that the miss was not ignition related or was bad wires, etc. Good luck.

gint · 01-07-2003, 10:56 AM

Thanks John. I've secretly been wanting something like this for a while now.

And I realized that my answer for Scott was not completely clear in my original reply. Sorry Scott. I prefer NGK's myself. I use them almost exclusively. Nothing fancy, just a good solid and always reliable spark plug. I've never had a single problem in 20 years of use.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The "cheapie" Bosch Platinum plugs that all the auto parts stores sell are junk, IMHO. The "plus 4" and "plus 2" (or whatever they're called) are the same junk, just with extra electrodes.

Bosch copper plugs are just fine for most uses. Not sure about the gap, though--you can try backing off to 040 and see if that helps.

--DD

DNHunt · 01-08-2003, 08:30 PM

I've been running an MSD 6A, Blaster 2 coil MSD heli-coil spark plug wires with a Pertronics for about 6 weeks now. Not long enough for a real evaluation but I feel it is a help on the low end.

The plugs are Bosch W5CC instead of the W7CC I used with the original points and condenser. I originally sent the gap at .050. It really ran well for a while.

About a week ago I started having a problem with misfires but mine occured at 2500 to 3500 rpms at light load. It still accelerated well. I checked all the connections and found nothing loose, rerouted some of the wiring (including the signal wire which was touching the coil) and regapped the plugs to .041. The car drives great again.

The problem is I don't know if the fault was a loose connection, electrical interference or too much gap.

Dave