how do these plugs look, and are they the right ones?

[mostsmooth]

Hi all,

95 gt, gt40 heads.
i pulled the plugs to do a compression check. they have maybe 500-1000 miles on them.

lets say about half of those miles were with the fuel pressure regulator seal failed and dumping fuel into the vac lines and I would imagine the intake. not sure if that matters.
tips seem to look ok to me, but i don't know much.
my main interest is the black carbonish deposit near the end of the threads. the couple threads that i would imagine are exposed to the cylinder are black.

yes, #7 porcelain is cracked somehow. i dont know how that could happen? i didnt overtighten it. just a bad plug or is that indicative of some problem?

these plugs are AGSF32CA. these are the right ones for the GT40 heads i believe. i think i recall doing a bunch of research when i bought them a couple months ago.
but, does anybody know what the difference between AGSF32CA and AGSF32C? i need to replace one obviously and im having so trouble locating in parts stores. ford wont have them until monday, which isnt the end of the world, but if i can get it replaced before then, would be nice.

Thanks

 

[HemiRick]

plugs look normal, yes the black is because that part is in cylinder. You prob cracked the porcelain removing it. replace that plug.

 

[96pushrod]

Plugs look fine.

I always just ran auto lite 104 I’m gt40 headed stuff. You could replace the busted plug with one of those and never know the difference.

 

[mostsmooth]

i replaced the broken plug and as i was installing it, using a torque wrench, it felt weird. its for cylinder 7, so a bit of a pain to get to with the headers and oil dipstick and brake cylinder and such there. i started it by hand, always do, and only use the wrench once the plug is in deep and i know theres no cross thread issue.
so i loosened it up thinking it was too tight, and then torqued it. it felt weird again, went to loosen it again and it crumbled. broke in half. i practically crapped my pants as my brain raced thinking about now i have to take the heads off and figure out out to get the broke stump out of the head. then i realized duh the socket must still be available and i can just unscrew it. lol

but now, i mean, i was using 13.5 lbs which is at the high end of the torque range from what i understand (7-14 lbs). i did all the plugs that way and as far as i know this is the only broken one and i broke 2 of them. the plug threads seem fine. is it just likely that 13.5 is too much or should i be concerned about something else? the previous plug that i broke that was in there was 100% where it should have been depth-wise, its not like it was being blocked in some way.

i wasnt using any anti seize or anything

i guess i just buy another plug and use less torque, maybe 10 lbs? im sure some/most folks will say dont bother with the torque wrench, right? i never used a torque wrench for plugs ever, til recently. thought i would do things 'right'. seems to be working well for me...

 

[General karthief]

I ask: (I'm always asking) does the plug socket have a rubber/hard foam inside to cushion the ceramic?
If not, the socket can easily get crooked and break the top off a plug.
That's a tough place to keep the socket straight

 

[mostsmooth]

I ask: (I'm always asking) does the plug socket have a rubber/hard foam inside to cushion the ceramic?
If not, the socket can easily get crooked and break the top off a plug.
That's a tough place to keep the socket straight

Hi general,
This morning laying in bed,I realized that the torque shouldn't matter. As long as the wrench was on straight, 100 lbs shouldnt crack the porcelain, it would just ruin the threads or damage the head somehow. So I started thinking that maybe the socket wasn't as straight as I thought, or maybe right at the end of torquing the socket got out of line and broke the porcelain. The first one that broke, it was only cracked but the tip was bent on an angle. I assume now that the top was pressured, bent, and thus cracked the porcelain. I think the same thing happened this time but worse.
I will check that socket for the insert. Off the top of my head, I think this particular socket did not have the insert, but I could be wrong. Either way, I am thinking that at the end of the install, the socket got out of line because of the header tube or just a bad angle on my part and broke the plug.

Thanks

 

[Potomus Pete]

With all you have been through, and the risk of ruining the threads I would get the special socket. Anti seize would be on my list also.

 

[mostsmooth]

With all you have been through, and the risk of ruining the threads I would get the special socket. Anti seize would be on my list also.

i just checked, the socket does have the rubber insert, but it looks like it is deformed, like worn out. it is in a set of 3 sizes and the other 2 look much better. i will take a look at it more closely after work. it may just be molded to the shape of the plugs that the socket is used for.
as far as antiseize goes, i have antiseize, but i was under the impression that plugs these days, or maybe just the plugs with the shiny metal threads these days dont require antiseize and maybe even it would be bad to use?

 

[General karthief]

I think the anti seize would be used for aluminium heads stop over thinking the plug breakage, get another plug just be careful when installing, check the socket fits the plug good and get after it, oh, and check plug gap too, it's not rocket science, I've crunched a few plugs myself and I'm considered an expert in spark plug installation.
Known around the world
Well, maybe not the world but in this country
Well, not the WHOLE country but I am well know on my block

 

[revhead347]

I think the anti seize would be used for aluminium heads stop over thinking the plug breakage, get another plug just be careful when installing, check the socket fits the plug good and get after it, oh, and check plug gap too, it's not rocket science, I've crunched a few plugs myself and I'm considered an expert in spark plug installation.
Known around the world
Well, maybe not the world but in this country
Well, not the WHOLE country but I am well know on my block

I just learned for the first time in my life that modern spark plugs don't require anti-seize. Yeah, I've been gooping them up to, and that's the wrong way to do it, even on aluminum heads.

Don't sweat a broken spark plug. It happens all the time even to seasoned mechanics.

I just lost 2 afternoons of my life changing the spark plugs on my Ford 6.2L. I don't use a torque wrench for plugs, but I also don't put them in with a breaker bar like the last guy did. It was hours of unstretching the threads with a chaser.

Kurt

 

[General karthief]

I just learned for the first time in my life that modern spark plugs don't require anti-seize. Yeah, I've been gooping them up to, and that's the wrong way to do it, even on aluminum heads.

Don't sweat a broken spark plug. It happens all the time even to seasoned mechanics.

I just lost 2 afternoons of my life changing the spark plugs on my Ford 6.2L. I don't use a torque wrench for plugs, but I also don't put them in with a breaker bar like the last guy did. It was hours of unstretching the threads with a chaser.

Kurt

Not sure what you are saying here Kurt,
It is my understanding that modern heads need anti seize on the plugs and iron heads do not, is that correct?

 

[mostsmooth]

Not sure what you are saying here Kurt,
It is my understanding that modern heads need anti seize on the plugs and iron heads do not, is that correct?

Hmm, my impression was that modern plugs are coated, making antiseize unnecessary, and apparently the addition of antiseize could send the plug depeer into the cylinder causing problems. I think we need to get to the bottom of this.

 

[revhead347]

Not sure what you are saying here Kurt,
It is my understanding that modern heads need anti seize on the plugs and iron heads do not, is that correct?

What mostsmooth just said. Back in the old days we put anti-seize on plugs with iron or aluminum heads. Modern spark plugs have special coatings that prevent corrosion or binding on them so now they don't need antiseize. I literally learned this 2 weeks ago. There's a whole "please don't put anti-seize on our plugs" paragraph on the NGK website.

Kurt

 

[General karthief]

What mostsmooth just said. Back in the old days we put anti-seize on plugs with iron or aluminum heads. Modern spark plugs have special coatings that prevent corrosion or binding on them so now they don't need antiseize. I literally learned this 2 weeks ago. There's a whole "please don't put anti-seize on our plugs" paragraph on the NGK website.

Kurt

Well, there you go!
They didn't clear that with me!!
And why did you take so long to tell us?

 

[revhead347]

Well, there you go!
They didn't clear that with me!!
And why did you take so long to tell us?

I'm in training for a different airplane. I haven't been on here as much as usual.

Kurt

 

[96pushrod]

Hmm, my impression was that modern plugs are coated, making antiseize unnecessary, and apparently the addition of antiseize could send the plug depeer into the cylinder causing problems. I think we need to get to the bottom of this.

Antiseize won’t cause the plug to stick too far into the cylinder. It’s not going to change dimensions of the tapered or gasket seat.

I always put a SMALL amount on spark plug threads, and don’t over torque them. Whether it’s a coated ngk plug or coated autolite and I’ll continue to do so.

 

[mostsmooth]

Antiseize won’t cause the plug to stick too far into the cylinder. It’s not going to change dimensions of the tapered or gasket seat.

I always put a SMALL amount on spark plug threads, and don’t over torque them. Whether it’s a coated ngk plug or coated autolite and I’ll continue to do so.

i defer to your knowledge, but some questions so i understand:

as far as i know, torque is created from the bolt stretching, right? the threads keep going deeper while the head doesnt. seems to make sense that if you lube the threads you will let them move more easily and thus deeper? i would imagine the bolt material and such (insert physics verbiage here?) plays a part as well, and im not saying the tip of the plug will go an extra inch, but it seems it has to go further with lube. 10lbs without lube and 10lbs with lube have to give different results (depth) i would think, otherwise the world doesnt make sense. seems the bolt head cant go any farther in, but the threads can and will.

am i way off on this?

 

[96pushrod]

i defer to your knowledge, but some questions so i understand:

as far as i know, torque is created from the bolt stretching, right? the threads keep going deeper while the head doesnt. seems to make sense that if you lube the threads you will let them move more easily and thus deeper? i would imagine the bolt material and such (insert physics verbiage here?) plays a part as well, and im not saying the tip of the plug will go an extra inch, but it seems it has to go further with lube. 10lbs without lube and 10lbs with lube have to give different results (depth) i would think, otherwise the world doesnt make sense. seems the bolt head cant go any farther in, but the threads can and will.

am i way off on this?

You’re thinking about this way too hard.

 

[mostsmooth]

You’re thinking about this way too hard.

Story of my life

 

[revhead347]

Antiseize won’t cause the plug to stick too far into the cylinder. It’s not going to change dimensions of the tapered or gasket seat.

I always put a SMALL amount on spark plug threads, and don’t over torque them. Whether it’s a coated ngk plug or coated autolite and I’ll continue to do so.

It can lead to an incorrect torque spec if you are using a torque wrench, which theoretically could stretch the plug, which is a joke, because no one uses a torque wrench to put spark plugs in, and the torque required to mess up the threads is about 10 times the factory torque spec, and anti-seize will not throw it off that much.

Kurt