Fun with busted spark plugs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Blackstone · 09-13-2007, 08:21 PM

Well I got the '87 GMC registered, slapped my plates on and took it for a nice test drive. Ten minutes later.... tick, tick, tick, tick. The seller told me it should be due for a tuneup, but I never expected a spark plug to break in half... at least not without ever putting a wrench to it. Anyway, the plug broke off just like this, between the threads and the hex head:

Unless anyone else has a better idea, I've got a date with an easyout tomorrow night.

MylilBowTie · 09-13-2007, 11:58 PM

That's a great way to read a plug! I've never ever seen a spark plug do that. Maybe a bad plug, hope the rest come out better. I'm wondering what caused it to happen. I think I would use some anti-seize on the new plugs.

I would soak down the rest of the broke off part with some good penetrating oil. I like Kroil or PB Blaster.

Srubydo1986 · 09-14-2007, 07:52 AM

wow that a very odd break never seen that before

Blackstone · 09-14-2007, 09:48 AM

I've now learned that it's fairly common, caused simply by corrosion and not limited to any one brand. Upon pulling the rest of the plugs, I found a brand new Delco R44TS beside the broken CR43TS that the manufacturer recommends. Two of the plugs suffered from this condition.... obviously the reason the guy unloaded the truck. He certainly knew, because the other damaged plug was missing it's "hexed" portion and there's no way it fell off on it's own. That plug is still intact and operable, just unremoveable by conventional means.

The good news is that the R44TS plug has a thicker body than the CR43TS, ensuring that it never happens again.

The bad news is that I'm pretty sure the head needs to come off. I tried to turn the broken plug with a 1/4" flat screwdriver, which eventually worked it's way completely through, followed by a huge easyout which simply threaded itself completely through. I'm almost certain that the grounding electrode has at some point fallen into the combustion chamber. Of course, the broken plugs are in the worst possible spot, driver's side rear.

Blackstone · 09-14-2007, 11:40 AM

Well, I busted the first one loose with a larger easy out. The second one is going to need a bit more heat than a propane torch can provide.... Stay tuned.

MylilBowTie · 09-14-2007, 12:51 PM

Get it hot and put a wax candle on it. The wax should seep into the threads and help remove it. Heating it will not make the broken part come out easier. When you heat that part up it will expand making it tighter. Ideally you would want to heat up around the cylinder head. So that will expand and have the broken part cool. That will take pressure off the broken piece.

May want to try to see if removing the exhaust manifold is an option. I would much rather pull a manifold than the cylinder heads. It should open up the area pretty good.

Blackstone · 09-14-2007, 02:04 PM

I probably won't need to remove the manifold. Cutting the bottom 2" of the inner fender (it was junk anyway) gave me easy access to both plugs. I heated the head around the plug to no avail, but I'll give the wax trick a try. I've heard it's quite effective.

Blackstone · 09-14-2007, 08:23 PM

DONE!

Acetylene RULES!!!

Srubydo1986 · 09-14-2007, 09:59 PM

yea id take the heads off just to be shure

09-13-2007, 08:21 PM	#1
Blackstone Registered User Join Date: Dec 2006 Location: Central Maine Posts: 210	Fun with busted spark plugs Well I got the '87 GMC registered, slapped my plates on and took it for a nice test drive. Ten minutes later.... tick, tick, tick, tick. The seller told me it should be due for a tuneup, but I never expected a spark plug to break in half... at least not without ever putting a wrench to it. Anyway, the plug broke off just like this, between the threads and the hex head: Unless anyone else has a better idea, I've got a date with an easyout tomorrow night.

09-13-2007, 11:58 PM	#2
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: Fun with busted spark plugs That's a great way to read a plug! I've never ever seen a spark plug do that. Maybe a bad plug, hope the rest come out better. I'm wondering what caused it to happen. I think I would use some anti-seize on the new plugs. I would soak down the rest of the broke off part with some good penetrating oil. I like Kroil or PB Blaster. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

09-14-2007, 07:52 AM	#3
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Fun with busted spark plugs wow that a very odd break never seen that before __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) 1970 chevelle 2dr sedan Latest update June 24 2007. *1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one

09-14-2007, 09:48 AM	#4
Blackstone Registered User Join Date: Dec 2006 Location: Central Maine Posts: 210	Re: Fun with busted spark plugs I've now learned that it's fairly common, caused simply by corrosion and not limited to any one brand. Upon pulling the rest of the plugs, I found a brand new Delco R44TS beside the broken CR43TS that the manufacturer recommends. Two of the plugs suffered from this condition.... obviously the reason the guy unloaded the truck. He certainly knew, because the other damaged plug was missing it's "hexed" portion and there's no way it fell off on it's own. That plug is still intact and operable, just unremoveable by conventional means. The good news is that the R44TS plug has a thicker body than the CR43TS, ensuring that it never happens again. The bad news is that I'm pretty sure the head needs to come off. I tried to turn the broken plug with a 1/4" flat screwdriver, which eventually worked it's way completely through, followed by a huge easyout which simply threaded itself completely through. I'm almost certain that the grounding electrode has at some point fallen into the combustion chamber. Of course, the broken plugs are in the worst possible spot, driver's side rear.

09-14-2007, 11:40 AM	#5
Blackstone Registered User Join Date: Dec 2006 Location: Central Maine Posts: 210	Re: Fun with busted spark plugs Well, I busted the first one loose with a larger easy out. The second one is going to need a bit more heat than a propane torch can provide.... Stay tuned.

09-14-2007, 12:51 PM	#6
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: Fun with busted spark plugs Get it hot and put a wax candle on it. The wax should seep into the threads and help remove it. Heating it will not make the broken part come out easier. When you heat that part up it will expand making it tighter. Ideally you would want to heat up around the cylinder head. So that will expand and have the broken part cool. That will take pressure off the broken piece. May want to try to see if removing the exhaust manifold is an option. I would much rather pull a manifold than the cylinder heads. It should open up the area pretty good. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

09-14-2007, 02:04 PM	#7
Blackstone Registered User Join Date: Dec 2006 Location: Central Maine Posts: 210	Re: Fun with busted spark plugs I probably won't need to remove the manifold. Cutting the bottom 2" of the inner fender (it was junk anyway) gave me easy access to both plugs. I heated the head around the plug to no avail, but I'll give the wax trick a try. I've heard it's quite effective.

09-14-2007, 08:23 PM	#8
Blackstone Registered User Join Date: Dec 2006 Location: Central Maine Posts: 210	Re: Fun with busted spark plugs DONE! Acetylene RULES!!! Last edited by Blackstone; 09-14-2007 at 08:23 PM.

09-14-2007, 09:59 PM	#9
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Fun with busted spark plugs yea id take the heads off just to be shure __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) 1970 chevelle 2dr sedan Latest update June 24 2007. *1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.