# Bent Spark Plug Electrode



## MWheeler76 (Sep 19, 2015)

Hi, my name is Matthew, owner of a '03 Altima with the QR25DE. The situation is taking place in the #4 cylinder. These plugs have been in the engine for almost 30 K, flawless. However, they are not OEM NGK. I'm using the double platinum Denso PKH16TT. Believing that there may be a foreign object (carbon, catalyst, etc.), I let it idle for about 5 mins. without the spark plug in, hoping it would blow out. The entire top surface of the plug looks as though it was used as a BB gun target, with the ground electrode mashed down to the center (core) electrode. I bore scoped the cylinder, though very limited, due to poor illumination from the internal light and manual operation of the flex cable. Unfortunately, nothing was found. The engine has no internal leaks of any kind, from what I can see. The cylinder wall looks great, no scoring, just smooth. However, there is carbon deposit on the piston head, as expected. The level of severity, unknown to me, due to not being a mechanic and this being my first internal view of a used piston. Though, there is no sign of bare metal exposed in the center of piston, showing the possibility of collision with plug. I would imagine, if that was the situation, I would have a far worse deal going on. I can have it idle, then slowly run through the rpm's, holding at 2K, 2.5K, 3K for a minute or so each increment. Everything sounds great and feels smooth. Take it down the road a couple of miles or so, then back to a mashed electrode!!! Unreal... any suggestions would be incredibly welcomed.


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## Gonz209 (Aug 30, 2020)

Hello how you doing I was wondering what ended up being the problem with your car denting your spark plug, my 06 Altima 2.5 engine is doing the same, thanks.


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## rogoman (Dec 16, 2004)

The spark plug you are using may have a "reach" that's longer then OEM causing the piston to touch the plug electrode. The standard plug type is an NGK PLFR5A-11.
It's also possible that there may be an excessive buildup of carbon on the piston head, although it's rare.


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## Gonz209 (Aug 30, 2020)

Thanks for the reply, this engine actually still had the OEM NGK plugs. This engine is a replacement bought from the Japan Motors with 50-60k miles on it. It's been running fine the out of nowhere misfire piston 4 and found spark plug gap closed and looked like something was hitting it? Never seen anything like that before


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## smj999smj (Jan 1, 2006)

Gonz209 said:


> Thanks for the reply, this engine actually still had the OEM NGK plugs. This engine is a replacement bought from the Japan Motors with 50-60k miles on it. It's been running fine the out of nowhere misfire piston 4 and found spark plug gap closed and looked like something was hitting it? Never seen anything like that before


Is the exhaust manifold/catalytic converter original? They were known for having the catalyst substrate break down, which could get sucked into the engine past the exhaust valve during the variable valve timing's EGR process. If it is, you may want to remove the exhaust manifold and have a look of the engine side of the catalyst substrate, if you can see it...or, replace it.


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