Greetings, new member here. I just got my car back from having upgrades done. Unfortunately on the drive home my C3 started backfiring. I checked things over and discovered that two of the spark plug wires going to the two front, right side cylinders had burned off all their insulation. These are brand new MSD plug wires :(. I have Doug's headers and side pipes on the 1978 pace car. Obviously my mechanic had poor luck routing the wires. Do any of you have suggestions or a diagram on best practices for plug wire routing? Shielding from heat? I appreciate any and all help. Crying shame as I really want to break her in....now at projected 435 HP with upgrades.
Please note, I do not blame or fault the mechanic. Murphy's law in effect on this one and I know he'll make things right.
Vette(s): 1969 convertible L71 427/435 4-speed black interior
It seems that maybe the wrong set of plug wires may have been installed...angled boots vs. straight boots or vice-versa. Your headers may require the opposite boots of what was installed. Maybe they need to be routed differently...tough to say without actually seeing it.
You can buy plug wires with high heat boots and there are also additional protective boots available to fit over the wires to help protect them.
Your application may require a different spark plug...the same heat range but a shorter ceramic for header use.
It doesn't sound like you have a serious problem, just the right routing of the wires or a different boot or spark plug application.
Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, c o c k y and in general a malcontent.
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Hey, I appreciate the response ! Yes, I used the 90 degree MSD's as speced for the car with the HEI 90's on the power side. Routed beneath headers and am guessing needed more wire ties to pull them down further and tied off at each boot. I am unaware of other means of shielding the wires (you referred to them as, 'boots"? Any link available or a brand name? Seems to be adequate clearance with the plugs and boots just wire burn through. Wondering if I need to wrap the headers though I hate to as I had them Hot jet Coated with black ceramic.
Chris Welcome, I just went thru this myself as both my vettes burnt plug wires this week. I found the shorty plug that is made by Accel. They are 1/4" shorter which doesnt seem like much but it get the wire farther away from the header. I also use a protective High heat boot, but with a standard plug length the boot still burns and causes issues. The 1/4" is just enough room to allow the wires not to touch. i bought the plugs at Advanced auto parts. I hate that store but they had them on the weekend in stock. They also have boots as well Good luck Rodney Hake
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