I was helping Jack Curtis, a member of the GMC Classics, install a HEI
distributor in another Classics member's GMC and we discovered an error in
the maintenance manual. In chapter 6Y-50 in figure 50 it shows a diagram as
to how the plug wires should be installed in the distributor cap. The
picture (which mechanics use instead of the writing) shows the wires going
into the cap in this order: 1-8-4-6-3-5-7-2. There is text in the figure
that shows the firing order to be: 1-8-4-3-6-5-7-2. We did not see the
discrepancy at the 3 and 6 position. We had a rough running 455. Jack
finally discovered the discrepancy in the maintenance manual and when we
switched the 3 and 6 wires at the distributor everything smoothed out. I
checked my maintenance manual 75/76 X-7525 and it also had the discrepancy
but the 76 supplement X-7625 showed the numbering correctly.
I just thought that I would throw out this discrepancy so if someone is
trying to replace their plug wires, they need to read the writing as well as
looking at the pictures in the maintenance manual.
Jack said for me to be sure to tell Ralph Luby of this discrepancy. Since
Ralph monitors the net I consider he has now been informed.
Russ Bethel
grbethel
distributor in another Classics member's GMC and we discovered an error in
the maintenance manual. In chapter 6Y-50 in figure 50 it shows a diagram as
to how the plug wires should be installed in the distributor cap. The
picture (which mechanics use instead of the writing) shows the wires going
into the cap in this order: 1-8-4-6-3-5-7-2. There is text in the figure
that shows the firing order to be: 1-8-4-3-6-5-7-2. We did not see the
discrepancy at the 3 and 6 position. We had a rough running 455. Jack
finally discovered the discrepancy in the maintenance manual and when we
switched the 3 and 6 wires at the distributor everything smoothed out. I
checked my maintenance manual 75/76 X-7525 and it also had the discrepancy
but the 76 supplement X-7625 showed the numbering correctly.
I just thought that I would throw out this discrepancy so if someone is
trying to replace their plug wires, they need to read the writing as well as
looking at the pictures in the maintenance manual.
Jack said for me to be sure to tell Ralph Luby of this discrepancy. Since
Ralph monitors the net I consider he has now been informed.
Russ Bethel
grbethel
