misfire on number seven

[lagbolt]

1997 explorer 5.0 with James duff stainless headers keeps burning thru my heat shield to number 7 spark plug wire. I already have a steal wool protector on the boot but it still gets so hot that it melts the rubber boot. Does anyone have another alternative for spark plug boot so this doesn’t keep happening? Once it melts thru I get a misfire on cylinder 7 and have to replace the wire.

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[DirtDonk]

The only thing I can think of is to replace it with one of those porcelain wire ends that is down by the plug in place of the boot.
But since it’s burning above the level of your current braided protection, I’m not sure the ceramic boot would be long enough to do the job.

Or is that burning through the insulation to get to the wire and you just have it peeled back for the picture?

 

[lagbolt]

The only thing I can think of is to replace it with one of those porcelain wire ends that is down by the plug in place of the boot.
But since it’s burning above the level of your current braided protection, I’m not sure the ceramic boot would be long enough to do the job.

Or is that burning through the insulation to get to the wire and you just have it peeled back for the picture?

It’s burning through the insulation.


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[DirtDonk]

Any chance that you got a later set of P heads instead of the normal 97 GT40’s?
I thought it was the passenger side that always had the tight clearance between the header tube and the spark plug on the P heads, but maybe your combination is just too tight there.

But it does sound like the porcelain one would work if there is clearance for it. They’re fairly large diameter and non-flexible.
Look up Accel or Jacobs ceramic spark plug wires if you haven’t already seen them.

 

[lagbolt]

Any chance that you got a later set of P heads instead of the normal 97 GT40’s?
I thought it was the passenger side that always had the tight clearance between the header tube and the spark plug on the P heads, but maybe your combination is just too tight there.

But it does sound like the porcelain one would work if there is clearance for it. They’re fairly large diameter and non-flexible.
Look up Accel or Jacobs ceramic spark plug wires if you haven’t already seen them.

Definitely p heads, I had the valve covers off and it’s say it on the heads. I’ll see what I can find in ceramic. Thanks.


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[reamer]

make a heat shield between head and plug wire

 

[Master Chief]

I have Design Engineering, Inc protect-a-boot (DEI) on my 331 (1997 Explorer GT40 iron heads & Hedman headers) and see the titanium version of their boot/wire protectors received a positive GT40P head review on Summit Racing.

Roger


"GT40P heads compatibility. Used these to protect the plug wires on my 351W with GT40P heads. They have done well keeping the wires and boots cool. The instructions say not to let them touch the headers but with GT40P heads they do touch. So far, that has not been a problem. They seem to be holding up.
MICHAEL · Reviewed on Summit Racing Equipment"

 

[TNcowboy]

Design Engineering also makes exhaust wrap that will help if the Protec-a-boot isn't enough (https://www.designengineering.com/titanium-exhaust-wrap-2-x-33/)