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I've been having some problems with a very slight miss in my engine. I figured I would look at the spark plugs and see what's going on. My number one plug was black. So I looked closely at the number one spark plug wire. Here are photos of what I found. The wire got up against one of the header tubes. I installed a spare wire and new spark plugs. She is running great now.
The wire set is from Davis Unified Ignition. Live wires have a protective loom over the length of the wire. They have held up well in close proximity to the headers.
Welcome to the club. I took my car in for an inspection a while back and the mechanic comes back to me saying I have a miss, from either a wiped cam or a blown cylinder. It wasnt very noticeable, just the slightest BUMBUMBUMBUMbumBUMBUM....
I got home and prepared to tear down my engine. (I was on the verge of tears. The engine was only 3K miles old) The first spark plug wire I pulled (sleeved in asbestos like pictured in this thread) was burned out and arcing on the head.
DO NOT trust those asbestos sleeves to provide the heat protection you need. I had to dent the hell out my headers to get enough clearance to stop melting wires, even with the sleeve. Do not let the sleeve touch the header. You NEED some air gap.
Welcome to the club. I took my car in for an inspection a while back and the mechanic comes back to me saying I have a miss, from either a wiped cam or a blown cylinder. It wasnt very noticeable, just the slightest BUMBUMBUMBUMbumBUMBUM....
I got home and prepared to tear down my engine. (I was on the verge of tears. The engine was only 3K miles old) The first spark plug wire I pulled (sleeved in asbestos like pictured in this thread) was burned out and arcing on the head.
DO NOT trust those asbestos sleeves to provide the heat protection you need. I had to dent the hell out my headers to get enough clearance to stop melting wires, even with the sleeve. Do not let the sleeve touch the header. You NEED some air gap.
Scott, I had been burning even "heat proof" plug wire boots with no direct contact with the headers until I started using the sleeves. Since then problem solved. You're right- max air gap is your friend but there's only so much room between 2" primary tubes and the wires. Perhaps the heat coating on my headers is giving me just enough extra help to allow the sleeves to make the difference.
I ordered a new set of wires and wire sheathing yesterday. I have used the spark plug sheathing before. Yes it works great. The spot where this wire was burned was hidden behind the #5 header tube. I'm using the under the header wire sets. I didn't know that it was so close when it burned. I will definitely be covering the new wires with some heat proof covers on the next go round. Stay tuned.
I'm using Taylor Spiro Pro 8mm wires, which come in a bunch of different colors. You have to cut these to size and choose between conventional terminals or HEI- both are provided. A good crimping tool is needed for a clean job. You also need to make sure your looms are made for 8mm wires. There are a number of options, depending on your preference in style. I can't find the box they came in but here's a link for them in black- https://www.summitracing.com/parts/tay-73051/overview/
You should take a look under the hood in the dark for anymore bad wires. 
Found My Engine Miss Today
Yes you need an air gap between plug wires and header pipes/manifold - no contact no matter what material.
