LR Mechanics,
I had been experiencing a bit of a miss in my Mazda for about a month last winter, so I purchased a set of NGK plugs in December 2014. To my surprise and luck, it completely resolved the issue. However, On Wednesday, Feb 17, 2015 I experience a sudden power loss followed by engine miss and a few back-fires. I was a block from my mechanic, so I limped it in to see what was going on. What they found was quite shocking. The center electrode as well as the ground electrode came off the plug for cylinder #1. After several compression tests, a bore scope analysis and re-install of a new replacement plug, everything seemed to be fine. We assumed the broken piece exited through the exhaust valve (VERY LUCKY!) Regardless, I sent the plug to NKG for analysis. Here's what they said:
NGK USA Inc. has received one TR551X for inspection of a missing ground and center electrode. Upon inspection the missing ground and center electrode are evident. When a spark plug has a failure that includes missing electrodes, this is a direct result of one of two things. The plug cannot transfer heat and/or vibrational issues or both. As seen below, the ground electrode weld is still intact on the base of the spark plug and the torsional breakage of the ground indicates that this ground electrode failed because of vibration and uncontrolled combustion.
Vibrational failures can occur for many different reasons; however this plug failed from 2 different causes. The two causes of the failure in this case include incorrect torque on the spark plug as well as incomplete combustion. When there is exhaust making its way past the seat of the plug, this tells us that the plug was not fully torqued in the cylinder head as exhaust gas made its way past the seat as seen above. The incomplete combustion can be seen above as well in what is known as side spark. Side spark occurs when the ignition voltage finds an easier path to ground other than between the center and ground electrodes. As seen above. the dirt and oil on the top of the spark plug bridge the gap between the ribs used to stop the voltage and; as a result the voltage is discharged to the shell for some time creating incomplete and uncontrolled ignition events. What cannot be determined is whether the ground electrode failure or the side spark occurred first. The vibration and uncontrolled ignition events lead to the failure of this plug please be aware that NGK USA Inc. cannot guarantee proper performance of incorrectly installed and contaminated spark plugs. As a result it is the decision of NGK USA Inc. to deny this claim against our product.
Blah, blah, blah. Basically, they said it was my fault that I didn't torque down the plug enough. My mechanic said that was crap, he would have noticed when he pulled it. Oh well, I moved on...until Saturday. My wife and I were ironically on our way to the Mercedes dealership to pick up her new car from the detail shop. About a quarter mile away, the Mazda started buck'n and snort'n again. I barely got it to the dealership. To make an already long post short, a technician from the dealership scanned the engine code--bad ignition coil. I replaced it and still couldn't get it to idle smoothly. He pulled the plug and voila! The ground electrode was bent! The technician immediately asked, "Are you sure you know where the piece from the other plug went 'cause something hit this?" I told him my mechanic looked for it with a borescope and couldn't find anything and it's been running like new since the incident. We gapped the plug to get me back on the road. I drove to the nearest auto-part store and purchased two plugs; one as a replacement and one for my glove box.
The Mazda's running great once again, but I don't trust it. Any ideas on what's going on? This is very bizarre!!
This post was edited on 3/16 8:12 AM by alaskanseminole
I had been experiencing a bit of a miss in my Mazda for about a month last winter, so I purchased a set of NGK plugs in December 2014. To my surprise and luck, it completely resolved the issue. However, On Wednesday, Feb 17, 2015 I experience a sudden power loss followed by engine miss and a few back-fires. I was a block from my mechanic, so I limped it in to see what was going on. What they found was quite shocking. The center electrode as well as the ground electrode came off the plug for cylinder #1. After several compression tests, a bore scope analysis and re-install of a new replacement plug, everything seemed to be fine. We assumed the broken piece exited through the exhaust valve (VERY LUCKY!) Regardless, I sent the plug to NKG for analysis. Here's what they said:
NGK USA Inc. has received one TR551X for inspection of a missing ground and center electrode. Upon inspection the missing ground and center electrode are evident. When a spark plug has a failure that includes missing electrodes, this is a direct result of one of two things. The plug cannot transfer heat and/or vibrational issues or both. As seen below, the ground electrode weld is still intact on the base of the spark plug and the torsional breakage of the ground indicates that this ground electrode failed because of vibration and uncontrolled combustion.
Vibrational failures can occur for many different reasons; however this plug failed from 2 different causes. The two causes of the failure in this case include incorrect torque on the spark plug as well as incomplete combustion. When there is exhaust making its way past the seat of the plug, this tells us that the plug was not fully torqued in the cylinder head as exhaust gas made its way past the seat as seen above. The incomplete combustion can be seen above as well in what is known as side spark. Side spark occurs when the ignition voltage finds an easier path to ground other than between the center and ground electrodes. As seen above. the dirt and oil on the top of the spark plug bridge the gap between the ribs used to stop the voltage and; as a result the voltage is discharged to the shell for some time creating incomplete and uncontrolled ignition events. What cannot be determined is whether the ground electrode failure or the side spark occurred first. The vibration and uncontrolled ignition events lead to the failure of this plug please be aware that NGK USA Inc. cannot guarantee proper performance of incorrectly installed and contaminated spark plugs. As a result it is the decision of NGK USA Inc. to deny this claim against our product.
Blah, blah, blah. Basically, they said it was my fault that I didn't torque down the plug enough. My mechanic said that was crap, he would have noticed when he pulled it. Oh well, I moved on...until Saturday. My wife and I were ironically on our way to the Mercedes dealership to pick up her new car from the detail shop. About a quarter mile away, the Mazda started buck'n and snort'n again. I barely got it to the dealership. To make an already long post short, a technician from the dealership scanned the engine code--bad ignition coil. I replaced it and still couldn't get it to idle smoothly. He pulled the plug and voila! The ground electrode was bent! The technician immediately asked, "Are you sure you know where the piece from the other plug went 'cause something hit this?" I told him my mechanic looked for it with a borescope and couldn't find anything and it's been running like new since the incident. We gapped the plug to get me back on the road. I drove to the nearest auto-part store and purchased two plugs; one as a replacement and one for my glove box.
The Mazda's running great once again, but I don't trust it. Any ideas on what's going on? This is very bizarre!!
This post was edited on 3/16 8:12 AM by alaskanseminole
