C2 Small block plug wire routing

[Randy S.]

Gentlemen,

Re 1966 327/300HP

I discovered today the cause of my intermittent ignition miss. ( Correction, the mechanic did )
My #5 plug wire insulation was cracked where it was rubbing on top of the clutch shaft Z bar. Delco 508N wires about 3 years old

I am looking at UPC 6 B3 trying to determine the routing of #5 wire. Assume wires are oriented 1,3,5,7 in the grommets/shielding from inside to outside. Can't tell for sure from the drawing.
Is there a clip that holds #5 wire near the heat shield? Should #5 wire be routed over the clutch Z bar or under?

I obviously don't want this to happen again

Randy

[Timothy B.]

Re: C2 Small block plug wire routing

Randy,

I hope this helps some, from my experence the #5 and #7 wires go on opposite ends of the rubber wire grommets. The same is true for the #8 and #4 on the other side and the rubber even has #'s molded into them.

These cylinders fire consecutively one after another and the high voltage can jump to the other wire if there not correctly set apart so take the time to route the wires correctly from the distributor down vertically through the grommets.

The #5 wire length you are working with could be to long. The wire should exit the spark plug and stay above everything and go to the lower bracket that holds the rubber grommet.

[Randy S.]

Re: C2 Small block plug wire routing

Tim,

Thanks. When removing the the damaged #5 wire this morning I noticed the numbers on the grommetts, something I failed to notice when I installed the wires 3 years ago . Interesting that UPC shows the orientation for the passenger side but not the drivers side.

Randy

[John H.]

Re: C2 Small block plug wire routing

Tim,

Thanks. When removing the the damaged #5 wire this morning I noticed the numbers on the grommetts, something I failed to notice when I installed the wires 3 years ago . Interesting that UPC shows the orientation for the passenger side but not the drivers side.

Randy

Randy -

Here's the plug wire routing/sequencing diagram (C1 illustration, but it never changed).

[Randy S.]

Re: C2 Small block plug wire routing

Thanks John,

Of course I just finished installing #5 wire about an hour ago. I was uncertain whether it should be inboard or outboard as the wire grommet can be installed either way. I installed with #5 inboard like your illustration. As Tim pointed out, it is important to separate 5 and 7 to minimize any crossfiring.

However the UPC 6 B3 shows the sequence on the passenger side as 8,6,2,4 ( inboard to outboard) contrary to the C1 illustration. Functionally I don't think it makes any difference as long as the adjacent firing wires are separated.

Randy

[George J.]

Re: C2 Small block plug wire routing

Randy -

Here's the plug wire routing/sequencing diagram (C1 illustration, but it never changed).


John,
I have noticed other GM drawings that seem to confuse the issue. I think the optional engine section if the '65 AIM (specifically the L84 section) has a drawing that appears to be different than the one you posted. Of course, yours makes more sense, but I'm posting this so others know that there is some conflicting information out there from the General himself. Maybe there's an idea for a tech article in there.

George
31887

[Ken A.]

Re: C2 Small block plug wire routing

AC Delco 508N wires are also made for a Chrysler 340 engine and thus have 2 wires that are too long, as the OP has discovered. These wires need to be cut off & reconfigured for an OE fit.