this time it appears only the #6 wire went up. I pulled the plug, which was brand new, and it still looks brand new. It doesn't look like it's ever been fired. Theres no oil on it, and it hasn't gotten lighter like the rest of them.

The wire has a large burn hole in it, about an inch and a half off the plug boot. Same exact spot it was last time.

Timing is correct, or thereabouts.

car is getting closer and closer to the cliff...

Eric

 

I have to put on heat resistant sleeves over my plug wires or my headers will smoke them. plus I have to put sleeves over any wires 5 inches near the headers.

 

Have you thought about getting a longer set of plug wires?
That way you can route them behind the block and underneath the headers. I'm thinking about doing the same because my wires keep burning through. They've never caught on fire though.

 

sorry i should have explained a little better. I have 8 inch DEI flame resistant sleeves on the wires, so they didn't burn on the header.

The fire came from the inside out, not the outside in. Meaning somewhere i have an electrical problem, and i have no idea where to start with it.

Eric

 

If that's the third time you've toasted that wire, it's no longer the "#6" plug wire. It is now the number "666" wire, and your engine is Satan. And I thought that Mephistopheles drove a Lexus... Oh, my bad. That's just who MAKES them.

What kind of wires are you using? Solids? Internal failure of an ignition wire and subsequent burning through the insulation is generally due to a broken conductor. If your wires are routed in such a manner that they are moving excessively from induced vibration, you could be breaking the wires internally. The resulting open circuit and gap will create deterioration of the condictor, making an ever-increasing gap inside the wire. Heat from the arcing inside the wire's insulation will burn through the outer jacket from the inside outward, as you describe. Solid (or spirally wound solids) will have a greater tendency to fail in this manner, but vibration can kill any kind of ignition wire eventually. They are made to be bent, but not to move constantly.

Install the replacement wires with enough looms and stand-offs to keep the vibration to a minimum. The factory routing under the deck and exhausts, and along the lower edge of the heads is actually not a bad route. Just trim the excessive lengths so that you don't have a long length of extra wire swaying in synchronization with engine motion.

 

The first set were taylor spiro pros, the set that just burned are Moroso spiral something or others.

Your theory seems to make sense, except for the part where it doesn't appear that the #6 plug ever fired at all. If you theory is correct, that cylinder would have been getting spark at least for a little while correct?