You guy's aren't running nitrous are you? I've seen the electrodes vaporized off of plugs due to this. Generally caused by lean mixture. Usually, the pistons aren't far behind.

It almost sounds like mechanical damage, like there is something hitting the plug. Are they the same reach as the stock plug?

Also, sometimes detonation can cause mechanical damage like you are seeing. I have 18,000 on my L and have never had the plugs out. Not heavily raced though.

Maybe a bad batch of plugs, with the electrode improperly welded on?

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Red 00"
Pro-M mass air
Swanson Chip
*******'s bed cover

 

Well, the Autolites are in. It seems to run good when floored but may not be as responsive when tapping it to a 1/4 or 1/3 of a pedal when cruising. It's hard to tell at 1:00 AM taking a short test drive.

The Splits that I took out looked like they were in good shape. No visible cracks or loose electrodes. I put pressure on all ground electrodes and tried to rock them back and forth. They were solid.

I will pull one of the Autolites out after I get home from work and the engine cools. Then we will see how they burn.

Jay, I think MRBBQMAN is the only one on the juice but he has had no problems. This is the first failure of the Splitfires in an L. The funny thing is 3 out of 8 failed. That's an awful big percentage. They are the same lengths on the center and ground electrodes as the stock plugs so nothing should be hitting.

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Later,
Chuck
Black 00
Chuck's Lightning Page

 

don't know what gaps everyone is using, but too large a gap with 10 plus psi will destroy any plug. just a matter of how often the plugs see 10psi. i run 12 psi on my paxton, and found the best gap to be 035, down from stock 045. on the splits i'm running .040, and will probably go down to 035-038 with lower pulley. with any brand of plug, if they see a lot of boost, the gaps are increasing quickly and need to be changed often

 

Breaking is a common problem with the NGK splitfires. I know this from another forum dealing with hi revving 4 cyl engines. Pretty much everyone stays away from the NGK's.

 

I pulled one of the Autolites tonight and it was a regular tan color. I probably had about 40 miles on it and could have used a few more on it to make sure I was getting a good reading. The stock plugs where dark brown, the Splitfires where dark tan and these are regular tan. So, they run a little leaner than the Splits.

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Later,
Chuck
Black 00
Chuck's Lightning Page

 

Two of my motorcycle friend had them crack in their bikes ~ one was fatal

I have them in my 94 Mustang for about 4 years now. Clean them once a year and their still kickin strong. I probably won't put them in my bike or truck though.

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1998 XLT SuperCab w/ORP 4.6/auto/355LS

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