Spark plug blew up!??? |
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adkrock
Newbie Joined: July-22-2018 Location: Adirondack Mtns Status: Offline Points: 4 |
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Posted: July-22-2018 at 7:38pm |
Went for a ride last night in my 98 SNOB and cruising at 44mph. There was a 2mph drop in speed and then BANG! and pop pop pop pop. The ceramic part of a spark plug blew out and the threaded end stayed put. The popping was from the plug leaving a hole over the piston.
Anyone have any ideas what caused this? Thanks! |
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adkrock
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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Did all of the plug insulator including the center electrode blow out or did some of it stay in the cylinder.
I imagine you found the piece or pieces that blew out. A picture would go a long way toward maybe answering the "why" if you have any internal damage, it's already happened so a compression test would be a good start to see if there's damage. |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Bet it was not near as exciting as this plug failure was. The part on the right was the piece that was left threaded into my cylinder head Notice you can see the electrodes thru the hole.
Oh, by the way, it happened at about 3000 feet on takeoff in my plane. All came out good. Sure needed to change clothes though |
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Keep it as original as YOU want it
1978 Mustang (modified) |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4127 |
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That's why you shouldn't be in the air in anything that has plugs and carbs.
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75 Tique
Grand Poobah Joined: August-12-2004 Location: Seven Lakes, NC Status: Offline Points: 6127 |
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Exact same thing happened to me many years ago, with the added excitement of a fire under the engine cover. Same thing, ceramic section shot out of the metal base. Ignited gas followed. No damage. Was attributed to a plug not tight in the socket. Dont know if that is a real thing or not or if mine was really loose. I was concerned about debris in the cylinder. It was scoped and appeared to be fine. Ran it, and it was. But it did get my attention (tho probably not to the extent had it happened in a plane)
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_____________
“So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.” |
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MACS81SN
Senior Member Joined: May-27-2009 Location: NW OH / S. MI Status: Offline Points: 109 |
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For what it’s worth, my $.02 is that it’s a defective plug. Toured the Champion spark plug plant in high school. Plug is assembled by inserting metal seal, gasket, electrode, and insulator into the top the of the metal shell. Everything held together by a small rolled crimp on top of shell. Probably a bad crimp that held for awhile.
Decided during tour that I was never going to work on a factory assembly line. Never did. |
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Mark
1999 -SN - 502 Python 1981 - SN Owned 33 years - Sold 1968 - Mustang - Sold |
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gt40KS
Gold Member Joined: August-05-2017 Location: Wichita Kansas Status: Offline Points: 946 |
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Several possibilities come to mind as to a cause. Suffice to say a little research would be prudent before simply installing another plug and firing it up. One thought that comes to mind is a lean condition during high rpm run that ultimately caused a detonation. If so, the plug blow-out was a lucky outcome - could have been much worse. I'd pull the other plugs to see their color & condition as a start. Any engine work done recently?
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JCCI
1995 Ski Nautique GT40 |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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In my case I attributed the failure to the radius in the corner being too sharp and causing a stress riser. Of course Autolite never would agree but they did send me 12 new plugs. Not bad considering over $20 each. (They also kept my failed plug)
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Keep it as original as YOU want it
1978 Mustang (modified) |
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adkrock
Newbie Joined: July-22-2018 Location: Adirondack Mtns Status: Offline Points: 4 |
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Thanks for all the feedback! Will do a compression test and take a look at other plugs. Hoping there is no cylinder damage. Was suggested by a friend mechanic that it does occur but rarely. Got a week of rain in the forecast so plenty of time for diagnostics.
Thanks again!! |
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adkrock
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Oh now that's funny I worked very closely with the Failure Analysis Department with Allison Engine Company later known as Rolls Royce. You can usually limp back home with a dead cylinder but not with a turbine that spit blades out the exhaust. (at least with a single engine turbine) Saw many turbine engine failures, fortunately most were on the test stand. |
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Keep it as original as YOU want it
1978 Mustang (modified) |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4127 |
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That’s why we have two
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adkrock
Newbie Joined: July-22-2018 Location: Adirondack Mtns Status: Offline Points: 4 |
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554045175.jpg
Tried to post a pic and this is all that came up. How do you post a pic from your pictures? |
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adkrock
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Rockne,
Use the post reply or click on the full reply editor icon (arrow pointing to 2 o'clock) to open up all icons. Then click the tree with the up arrow icon. A browse box will come up allowing you to select anything off your computer. |
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