| [GMCnet] more on HEI distributor coil and pickup [message #102862] |
Wed, 13 October 2010 19:11 |
emerystora
Messages: 4442
Registered: January 2004
Karma:
|
Senior Member |
|
|
This was a recent subject on the GMClist and it has been covered in Duane Simmons ignition seminar several years back.
I have recently found some Delco tech information. This offers more complete information on this subject.
There are two color-coded (coil-in-cap) ignition coils, and three color-coded pickup coils. (Note that external
ignition coils are not color coded.) One coil-in-cap ignition coil uses red and yellow wires; the other
uses red and white wires. They are functionally identical except the magnetic (not electrical) polarity is
opposite. The yellow/red ignition coil is neither a higher- or lower-performance version of the white/red
ignition coil. They have the SAME electrical specs, differing only in the direction (not strength) of the
magnetic field they radiate.
One pickup coil uses either a yellow ty rap or a yellow plastic connector body on the wires that attach to
the module. Another pickup coil uses either a blue ty rap or black plastic connector body, and the third
pickup coil uses a clear ty rap or a clear plastic connector body. (Some aftermarket manufacturers will
use no connector body instead of a clear one.) The yellow pickup coil has opposite magnetic and electrical
polarity from the blue/black, and clear pickup coils. The wires leading from the blue/black; and clear
pickup coils to the module must be crossed to correct the electrical polarity, leaving the magnetic polarity
“backwards”. The metal connectors are sized differently; and the molded plastic connectors are positioned
in a way that prevents incorrect connection.
Delco discovered that magnetic interference from the starter/battery cable could trigger “false” sparks at
low RPM—especially during cranking. Sure, you can use mis-matched components—but if you have misfires,
backfires, or other ignition problems especially at cranking speed—you’ve been warned. Pickup coils
are selected based on engine family. Ignition coils are then selected based on which pickup coil was selected.
So, for the “traditional” V-8 engines, Chevrolet, Cadillac, and Olds Toronado use the yellow-coded pickup
coil, and because they use the yellow pickup coil, they use the yellow and red ignition coil. Put another
way, the yellow coils are a matched set. Buick, and Oldsmobile except Toronado, use the blue/black
pickup coil, and therefore use the white and red ignition coil. Pontiac uses the clear coded pickup coil. It
is wound the same way as the blue/black coil, but has longer leads to physically fit in the Pontiac version
of the HEI distributor. Therefore it, too, uses the white and red ignition coil.
Many parts catalogs indicate the wrong pickup and ignition coils for Olds Toronados.
Emery Stora
77 Kingsley
Santa Fe, NM
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
