When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Which post would be best *for spark plug wire routing* to be called #1? Obviously, any one of them can be used to start at #1, but from a routing/crossover point of view (and what did the factory do?), which post would #1 be best from which to start?
I pulled this image from another thread and modified it, so let me know y'all's thoughts by posting where ya think #1 would best be placed for easiest/best plug wire routing. Whichever one is picked, then it is CCW, 1-8-4-3-6-5-7-2 from there.
Last edited by rfpowerdude; Oct 30, 2023 at 10:57 AM.
I tried to download the image and edit it. My Droid is being dumb.
I thought there was only 1 right way to run your spark plug wires? 1, 8, 4, 3, 6, 5, 7, 2 starting from the distributor cap terminal and going CCW. I guess Chevy guys swap 4 & 7, don't they?
That's not the question. The order is not part of this (we all already know 1-8-4-3-6-5-7-2). What I am asking is which post do people typically use for #1? Any one of them can be used for #1 as long as the distr is installed with the rotor pointing at it when at TDC on firing. However, from a plug wire routing standpoint, there is probably an optimum starting point to call #1.
That's what I mean.
Last edited by rfpowerdude; Oct 30, 2023 at 10:58 AM.
IIRC the factory #1 plug wire was one position slightly CW/to the left of the point adjustment window on the cap. This is only matters for appearance, not operation
The "best" location is the one that minimizes spark plug wire lengths. Since you can install the distributor in any orientation, there is no "best" post.
There is probably an orientation that minimizes crossing the wires, but I haven't gone through the exercise of all 8 possibilities. I was hoping someone would say, " do it this way because that's the way the factory did it and here is the routing..."
Again, ASSUMING you have the rotor in the same orientation relative to the cam as when it came from the factory, yes the factory has a specific orientation for the #1 plug wire. And surprise, it's the one closest to the #1 cylinder.
Thanks Joe. That's the way I always did it, but 3 and 4 cross closely at the back and I was just wondering if anyone had a better starting point by experience.
Does someone have a 1974+ chassis service manual that has a pictorial of the plug wire routing for HEI? Of like Koda said, an actual underhood pic of routing? It's always been crossover messy and I was just trying to find a better way (if that exists).
Thanks Joe. That's the way I always did it, but 3 and 4 cross closely at the back and I was just wondering if anyone had a better starting point by experience.
3 and 4 will always cross. It's irrelevant. Worry about 5 and 7 crossing.
The real problem is 5 and 7 running parallel to each other. Since they are adjacent in the firing order, this can cause crossfire between the two cylinders.
Ah, true and 3 and 4 are too, but they’re on opposite sides so running parallel is not gonna be a problem. Seems that keeping 5/7 apart IS the difficult one.
Ah, true and 3 and 4 are too, but they’re on opposite sides so running parallel is not gonna be a problem. Seems that keeping 5/7 apart IS the difficult one.
Which is why the factory spark plug wire separators looked like this. The wide spacing was intended to keep the #5 and #7 wires apart.
Due to magnetic fields, parallel wires and cables are susceptible to cross talk (keep them separated much as possible), crossing wires and cables are not.
Thanks Jim, I am very familiar with that physics phenomenon (check my screename haha), I just wasn't sure if anyone had tried a different starting point for #1 to make routing easier/cleaner. I wonder of the Chevy guys have it any easier with the CW rotation...
Your over thinking it. Reference #1 post to #1 cylinder for easy reference when doing work. Unless your running solid core wires you have no need to worry about.
Joe V., per your post #10 above, the factory installation has #1 on the distributor cap pointing toward #1 on the engine and Joe P. mentioned about keeping 5 and 7 separated much as possible on the standard 2nd gen. Olds V8 firing order; if a 4-7 swap cam the two to keep separated are now 2 and 4. I think your sketch in post #17 may increase the possibility of 5-7 crossfire. I have not used an HEI distributor, but my '67 442 was equipped with the UHV ignition and I never had an issue of misfire even when using the Autolite solid core ignition wires which used to be popular. The UHV would give a solid (per a SUN tune up console) 40,000 volts at the plugs.
Upstate 442, I agree whole heartedly. I only mention that there was no misfire at 40,000 volts, CD ignition, even when using a strait stranded solid core plug wire. The currently available plug wires are way advanced from what we had available back then.
