Spark plug blew out the hole!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Renfro85 · 03-18-2010, 03:59 PM

so i had new exhaust installed on the truck today with a 1 in 1 out magnaflow, i made it about 6 miles down the road and then the number 1 spark plug went pop. im curious if the new amount of backpressure the truck has caused this or if it was just a freak coincidence. Btw its a inline 250 motor if that helps any

Arizona oldguy · 03-18-2010, 04:17 PM

It seems like this is an odd coincidence, the exhaust would only create pressure during the exhaust stroke and the exhaust valve would be open. The highest pressure would be during the compression stroke. I have a sneaky feeling that your plug hole was in bad shape, if the plug will not tighten up you made need to do a Heli-coil thread replacement. Most good auto part stores will have them. Good luck and God bless

GASoline71 · 03-18-2010, 04:19 PM

Or the plug was loose to begin with...

Gary

Renfro85 · 03-18-2010, 04:31 PM

well i did just replace the plugs last monday lol, maybe i over tightened or not enough, guess well see with the new plug

Leviticus · 03-18-2010, 04:38 PM

Man that sucks, like Arizona said you can usually get lucky and do a heli-coil but hopefully it didn't take all of the threads with it on the way out.

I had a Ferd V10 back in the day that was known for doing that but I was lucky it never happened to me before I sold it. Heard some horror stories of guys having to replace multiple sets of heads though.

Renfro85 · 03-18-2010, 04:41 PM

well the whole plug didnt blow just the white part, the rest is still threaded in the head, so im lucky i can get it out with a socket

PanelDeland · 03-18-2010, 04:46 PM

Possibly it was bumped during the exhaust install and blew out.Or maybe it was just a factory "bad plug".Glad to hear it was an easy fix.

Leviticus · 03-18-2010, 04:50 PM

Quote:

Originally Posted by Renfro85

well the whole plug didnt blow just the white part, the rest is still threaded in the head, so im lucky i can get it out with a socket

Oh, you're Golden then. Just pop it out and get some good quality pugs (Not sure what you were running before) and pop em in. Like panel said, if it got bumped and cracked it will blow out.

GASoline71 · 03-18-2010, 04:56 PM

It prolly didn't "blow out"... it "broke off".

Gary

Arizona oldguy · 03-18-2010, 05:25 PM

Lots of good advice goin on here. Check your plug socket, it needs to have a rubber insert, it will help you not break plugs when you are putting the El Paso cinch on em.

Leviticus · 03-18-2010, 07:15 PM

Quote:

Originally Posted by GASoline71

It prolly didn't "blow out"... it "broke off".

Gary

I think "Blow Out" sounds cooler

gkesseru · 03-18-2010, 07:44 PM

The only time I've seen this was with a cracked head. Coolant gets into the Cylinder and cannot be compressed. The term to cover is is "Oh you've hydraulic-ed your plugs."

mbgmike · 03-18-2010, 08:02 PM

We were at an All Harley Drag race about 10 or twelve years ago in Temple Texas. Joey Mancuso blew a plug out, It hit a tree limb about 3 inches in diameter above the stands and it fell into the stands right where no one was sitting and it was pretty crowded. It scared a bunch of people though

Renfro85 · 03-18-2010, 10:12 PM

i was using ac delco plugs, i put a new one in and so far so good. only bad thing about it, is i think some of the plug might have made its way through the radiator

RustyBucket · 03-19-2010, 10:19 AM

about 7-8yrs. ago a kid in my Son's band had a crappy little Furd Aerostar that blew the center white porcelain part of a plug out of the metal plug body. The base of the plug was still screwed in the head and the white part was in the wire boot hanging on the wire. Replaced it with a new plug and away he went. Think it was an Autolite------- my Son still has it. Never seen one do that in 50+ years.

Jacfourteen · 03-19-2010, 03:30 PM

prolly happened when you were torquing the plug, if you don't keep the socket centered then they will crack. I've done this a few times....and it was always after the parts store closed so I had to wait till the next day or put an old plug back in.

LONGHAIR · 03-19-2010, 03:44 PM

I have seen them blow-out before, but it was on a blown street rod. The white insulator is just crimped intop the top of the metal fitting.
I have even seen them un-screw and pop the entire plug out, but that was on a I6 Furd. Makes a horrible racket doesn't it?

Renfro85 · 03-19-2010, 05:24 PM

the noise was embarrassing to say the least, but yea all that was left of the plug was the threaded part.

03-18-2010, 03:59 PM	#1
Renfro85 Registered User Join Date: Jan 2010 Location: Alabaster,AL Posts: 36	Spark plug blew out the hole!!! so i had new exhaust installed on the truck today with a 1 in 1 out magnaflow, i made it about 6 miles down the road and then the number 1 spark plug went pop. im curious if the new amount of backpressure the truck has caused this or if it was just a freak coincidence. Btw its a inline 250 motor if that helps any

03-18-2010, 04:17 PM	#2
Arizona oldguy Registered User Join Date: Jan 2009 Location: Queen Creek Arizona Posts: 56	Re: Spark plug blew out the hole!!! It seems like this is an odd coincidence, the exhaust would only create pressure during the exhaust stroke and the exhaust valve would be open. The highest pressure would be during the compression stroke. I have a sneaky feeling that your plug hole was in bad shape, if the plug will not tighten up you made need to do a Heli-coil thread replacement. Most good auto part stores will have them. Good luck and God bless

03-18-2010, 04:31 PM	#4
Renfro85 Registered User Join Date: Jan 2010 Location: Alabaster,AL Posts: 36	Re: Spark plug blew out the hole!!! well i did just replace the plugs last monday lol, maybe i over tightened or not enough, guess well see with the new plug

03-18-2010, 04:38 PM	#5
Leviticus Shake and Bake! Join Date: Feb 2010 Location: Central Coast, CA Posts: 609	Re: Spark plug blew out the hole!!! Man that sucks, like Arizona said you can usually get lucky and do a heli-coil but hopefully it didn't take all of the threads with it on the way out. I had a Ferd V10 back in the day that was known for doing that but I was lucky it never happened to me before I sold it. Heard some horror stories of guys having to replace multiple sets of heads though. __________________ "All tyranny needs to gain a foothold is for people of good conscience to remain silent." Thomas Jefferson "You are remembered for the rules you break." General Douglas MacArthur "Support Our Troops And The NRA"

03-18-2010, 04:41 PM	#6
Renfro85 Registered User Join Date: Jan 2010 Location: Alabaster,AL Posts: 36	Re: Spark plug blew out the hole!!! well the whole plug didnt blow just the white part, the rest is still threaded in the head, so im lucky i can get it out with a socket

03-18-2010, 04:46 PM	#7
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Spark plug blew out the hole!!! Possibly it was bumped during the exhaust install and blew out.Or maybe it was just a factory "bad plug".Glad to hear it was an easy fix. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

03-18-2010, 05:25 PM	#10
Arizona oldguy Registered User Join Date: Jan 2009 Location: Queen Creek Arizona Posts: 56	Re: Spark plug blew out the hole!!! Lots of good advice goin on here. Check your plug socket, it needs to have a rubber insert, it will help you not break plugs when you are putting the El Paso cinch on em.

03-18-2010, 07:44 PM	#12
gkesseru Registered User Join Date: Dec 2009 Location: California, Maryland Posts: 544	Re: Spark plug blew out the hole!!! The only time I've seen this was with a cracked head. Coolant gets into the Cylinder and cannot be compressed. The term to cover is is "Oh you've hydraulic-ed your plugs." __________________ 72 Fleet (died) 78 Step (sold) 55 Step named Fred (sold) 00 F150 68 Step (named El Scorcho by PO) Build thread for the new El Scorcho http://67-72chevytrucks.com/vboard/s...d.php?t=392932

03-18-2010, 08:02 PM	#13
mbgmike Registered User Join Date: Aug 2005 Location: Pasadena,Tx /Pto Pta DR Posts: 5,415	Re: Spark plug blew out the hole!!! We were at an All Harley Drag race about 10 or twelve years ago in Temple Texas. Joey Mancuso blew a plug out, It hit a tree limb about 3 inches in diameter above the stands and it fell into the stands right where no one was sitting and it was pretty crowded. It scared a bunch of people though

03-18-2010, 10:12 PM	#14
Renfro85 Registered User Join Date: Jan 2010 Location: Alabaster,AL Posts: 36	Re: Spark plug blew out the hole!!! i was using ac delco plugs, i put a new one in and so far so good. only bad thing about it, is i think some of the plug might have made its way through the radiator

03-19-2010, 10:19 AM	#15
RustyBucket Registered User Join Date: Jul 2009 Location: Space Coast, Fl. Posts: 1,055	Re: Spark plug blew out the hole!!! about 7-8yrs. ago a kid in my Son's band had a crappy little Furd Aerostar that blew the center white porcelain part of a plug out of the metal plug body. The base of the plug was still screwed in the head and the white part was in the wire boot hanging on the wire. Replaced it with a new plug and away he went. Think it was an Autolite------- my Son still has it. Never seen one do that in 50+ years. __________________ Dad always said, "Son, WISH IN ONE HAND, and ......." -------------------------------------- -------------------------------------- Current toy trucks: '71 GMC 1500 SUPER CUSTOM short/step, orig. dk. blue, 350/700r, ps,pb, A/C '72 Blazer 2wd, ochre & white, 454, tremecTKO 500 5spd. ps, pb, A/C, tilt Last 10yrs of hobby vehicles, had a FEW more in the 50yrs. before these: '66 Plymouth Belvedere City of Miami cop car clone. '70 Nova 406"sb, 13.5-1, solid roller, Brodix, p.glide/t.brake, back halved, 9" Ford, spool 4.88, cage,ladder bar/coilover, 10.5 tire....... SOLD!! '67 C10 short/step side mount spare -- SOLD!! '72 Jimmy 2wd, 350/350, ps, pb, fun driver, lots of bondo & a shiny red paint job..... SOLD!! '69 Nova 350, 4spd, A/C, ps, p.b, ...SOLD!!

03-19-2010, 03:30 PM	#16
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: Spark plug blew out the hole!!! prolly happened when you were torquing the plug, if you don't keep the socket centered then they will crack. I've done this a few times....and it was always after the parts store closed so I had to wait till the next day or put an old plug back in. __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

03-19-2010, 05:24 PM	#18
Renfro85 Registered User Join Date: Jan 2010 Location: Alabaster,AL Posts: 36	Re: Spark plug blew out the hole!!! the noise was embarrassing to say the least, but yea all that was left of the plug was the threaded part.



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