Read my Spark Plugs please

[Paul T]

Can you read my Plugs? Left plug is number 5 with which I’ve had three burnt plug wires. Right plug is number 7. I decided to replace the spark plugs and the wires this time and would like you Spark Plug Readers to tell me what the black area is near the top of the left plug, (number 5). I assume its carbon and an indication of where the electrical energy was escaping through the connection end of the plug wire finding a ground somewhere other than where it should be creating a spark. Am I right?

[HoRotica]

I believe your assumption is correct. Plug gap looks BIG.

Chris

[Wanabee FTer]

Not sure but the left plug looks like it has a small crack at the top filled with black carbon. The spark will arc from the top of the plug through the crack. That would cause what seems like a bad spark plug wire, but could actually be the spark plug that has been giving you all the trouble.

["007"]

If your not getting enough air by your plugs the hot manifold is going to burn plug wires. Top of left plug maybe rubber burnt on porcelain from the wire connection boot.
Make sure your air-dam around your radiator is forcing air through radiator and you may need a vent kit feeding cool air to rear of your two manifolds.
Gaps do look large should be .60 or .45.
Mine are .45 with TAYLOR Wires & Ultra Power program for ECM.

[Wanabee FTer]

007 could be right, the way to tell what is causing the problem would be to wire brush/wheel the top of the plug to remove the burnt rubber. If there is a crack visible on the top of the plug, the new plug will fix it. If you do not find a crack then 007 suggestion to add a cool air duct to the exhaust manifold should solve it.

[Full-Timers]

Sometimes the connector will pull back from the plug a bit. This will cause arching from the connector to the plug. This might be what you see at the top of the left plug. After seeing your plugs, this makes me want to change mine.

["007"]

Here is more information on spark plugs.
Dale also has a vent kit that could be adapted for a vent kit for plugs & wires.

[DriVer]

When the spark plug wire overheats and quite possibly burns, the black circular trace that is seen on the porcelain is quite possibly molten material deposited from the boot.

In the future place the spark plugs on a white piece of paper and use more lighting.

[HeapBigEngin]

A few questions....how's the vehicle running? Is it missing? What else, if anything, may be going on here besides burned wires? Stumbling, surging at speed, bucking, etc.? How many miles on the vehicle? If it is running fine and only the wire(s) are burned, then it would almost have to be an external problem. Since both plugs (5 & 7) are on the same engine "bank", could there be something there that is causing the wire(s) to overheat on that side?

Cracked porcelain on a plug usually causes a miss or other driveability issues. It is not hard to crack the porcelain if you're working in very tight, dark quarters and you have to "force" things or if you're using socket flex joints to get the plugs in/out. Plug porcelain is much easier to crack than some might think (believe me, I know!). Cracked porcelain oftentimes requires a magnifying glass to truly identify. Cracked porcelain or overgapped plugs don't burn wires....they cause other problems. And burned wires don't crack plugs. I agree with others....tough to tell from these pics, and the gaps look awfully wide. I think more info would help find the problem....

[DriVer]

Quote:

Originally Posted by heapbigengin ....tough to tell from these pics, and the gaps look awfully wide. I think more info would help find the problem....

The plugs in the 8.1L engine are OE @ .065 they get wider from that point.

Paul T
There have been several 38Ts that we have read about here that have shown improvement using the after market cold air vent kit. You might want to look into that option.