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spark plug exploded?
Had a very unusual occurrence the other day. I actually blew up a spark plug. It didn't leave the car or anything. We just removed it and the white ceramic insulation completely separated from the metal. The center metal core and tip moved within the threaded shank. Any thoughts on how this could occur? They had about 29k miles and were due to be changed anyway, but I'm wondering if there is something else besides wear & tear that would explode a spark plug?
Wires, cap, rotor and plugs all had about 29k miles on them. Never had this happen before.
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65 356SC Cab - 70 T Sunroof Coupe - 82 SC Targa - 86 Coupe - 87 Targa - all sold years ago 89 944S2 Daily Driver-Sold because...still thinking why. 73.5CIS Targa Shed Find -On the Road Again |
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02-21-2009, 06:01 PM
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rattlesnakeracing
Join Date: Jan 2009
Location: Eastern North Carolina
Posts: 101
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Hot Rod!
It could have been over torqued with enough pressure to make the plug have an undetectable crack. Heat and time could have worn it enough that it finally grounded out the side and popped the plug. The correct torque with a torque wrench would be 18 to 22 Ft-lbs or 25 to 30 Nm.
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87 Charcoal Metallic 944{Proj} 88 White Pearl 944{Daily Driver} 87 Silver Mazda RX-7{210K no rbld} 87 Charcoal Mazda RX-7 GSL{Proj} 88 Gold Met RX-7{Parts} 89 Midnight Black Mazda RX-7 Conv.{Proj} 87 Intl. Scout II{Proj} 99.5 Nissan Pathfinder LE {Daily Driver} USAF (Ret) GO Blue! - - RattlesnakeRacing - Don't Tread on Me!
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02-21-2009, 09:20 PM
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I tend to agree. From the sounds of it, your plug got way too hot. Can you see rings near the base of the ceramic part of the other plugs left?
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Ed Paquette 1983 911SC 1987 944S 1987 944 Manual (Donated to the Nat. Kidney Foundation) 1987 944 Automatic (Recently sold to another Pelican) |
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02-21-2009, 09:24 PM
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Registered
Join Date: Nov 2003
Location: Calgary, AB
Posts: 1,883
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I always install spark plugs with a torque wrench, and during about a 4 month time frame on my 951 I went through 10-12 spark plugs because this same thing kept happening. After dumping ~$15 on spark plugs at one store I finally went to a different one and the issue disappeared. In my case I think they had been handling them too roughly before selling them. Not sure how much that applies to you, but there's my story on the same problem
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2010 Hyundai Elantra Touring, GLS 5 speed, Indigo Blue Metallic. 2.0L of Korean fury! Buy my parts! |
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02-21-2009, 11:39 PM
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Thank you all for the thoughts.
Hadn't thought of something as simple as torque or even how the plugs were handled. The plug other than being separated looked quite normal in it's burning. I'm going to look a bit more closely at the the other 3 plugs and see what they tell us now that I know I may have a problem. I went onto the NGK web site and they had a few other ideas, most of which will be quite time consuming at best and probably more expensive to resolve. Here's the link if any one is interested. This is the problem page. http://www.ngksparkplugs.com/tech_support/spark_plugs/p5.asp?mode=nml This is the beginning of the write up. http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml
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65 356SC Cab - 70 T Sunroof Coupe - 82 SC Targa - 86 Coupe - 87 Targa - all sold years ago 89 944S2 Daily Driver-Sold because...still thinking why. 73.5CIS Targa Shed Find -On the Road Again Last edited by Robert Adams; 02-22-2009 at 01:23 PM.. |
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02-22-2009, 10:11 AM
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Join Date: Feb 2008
Posts: 18,724
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the same thing happens to my dad's benz. but at first they were the cheap auto zone plugs then we changed them to the Bosch, now instead of 4 going bad it's down to one. I think that cylinder has a burnt valve now
 
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dolor et pavor Copyright |
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02-22-2009, 10:16 AM
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1973 Porsche 911
1983 Porsche 911SC Targa
Eggplant
