Plug blow-out...took a piston with it this time!

svttech76 said:

My guess is the original thread repair was done with a cheap repair kit.. those cheap kits can cause hot spots in the chamber and in the worse case cause what happened here..


Timesert is a good kit for plug blow out and now helicoil has a dedicated kit just for modular plug blowout, we have been using that kit at work and it seems to be fine.

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Notchbck93 said:

Yes, but you very well know that as a Master Tech, who I'm sure posses L1 as well, your balz will be pressed in a vice if you were the last guy who worked on the vehicle.

I also entertain the idea of a long helicoil causing pre-ignition except for the fact that Ford uses extended plug threads in which the helicoil would simply wrap the threads which would help with heat transfer of the threads to the plug. I would not rule out the helicoil glowing before the plug, but with the nature of the arc plug being longer than the threads themselves, I have to question pre-ignition.

Perhaps we haven't heard about a custom tune being installed on this car, lack of EGR function, and/or clogged injector, intake/exhaust manifold leak or any combo of these things that played a part in taking out one of his slugs.

Maybe the mech didn't pull the tang out and just bent it out.

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svttech76 said:

When this problem first started getting bad around 2002 or so, ford wanted us to replace the head when a plug came out. One of the reasons for this was preignition caused by heat transfer issues between the plug and cyl head..

then better kits came out and now they want us to repair the hole. using a aluminum insert

Plenty of other factors could have caused it we will never know for sure.


if he did have a misfire it might not have set the light if it was not constant. or if the KAM was reset and misfire monitor was not
ready. Who knows it might have even had a p030x in the system pending but not have turned the lite on yet since it would have been a type b miss.. I think he would have noticed a type A miss regardless of the flashing CEL that would cause..

sure any miss would cause a lean reading on that bank right after the misfire but it would not be enough on a miss that is not steady to change the long term trims enough to set a lean code for that bank.

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svttech76 said:

When this problem first started getting bad around 2002 or so, ford wanted us to replace the head when a plug came out. One of the reasons for this was preignition caused by heat transfer issues between the plug and cyl head..

then better kits came out and now they want us to repair the hole. using a aluminum insert

Plenty of other factors could have caused it we will never know for sure.


if he did have a misfire it might not have set the light if it was not constant. or if the KAM was reset and misfire monitor was not
ready. Who knows it might have even had a p030x in the system pending but not have turned the lite on yet since it would have been a type b miss.. I think he would have noticed a type A miss regardless of the flashing CEL that would cause..

sure any miss would cause a lean reading on that bank right after the misfire but it would not be enough on a miss that is not steady to change the long term trims enough to set a lean code for that bank.

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Notchbck93 said:

I too have studied the thermodynamics of how SS doesn't transfer heat as well as the more practical alum inserts. SS inserts obviously would cause the plug to become warmer as it couldn't transfer the heat as well through the SS into the aluminum. Two steps colder on the plug would have worked as well, but that's for an engineering forum, not on here, where no one really cares.

As far as the KAM, unless he had a battery disconnect that he shut off every time when he left the car, I find it hard to believe that it would just erase every night.

You understand that the dummy HEGO only reads O2 and how different scenarios can lead to false impressions. Then you would also understand that even in a case of pre-ignition, not ark blow out or incomplete, where 02 levels would rise, also by a lean condition, but in pre-igition, it can still register to the 02 sensor as complete combustion.

I don't think we would be looking at a problem of complete combustion here though, I think we would need to be looking to the crank angle sensor to paint us a better picture.

It would be nice if the poster had included pics of his damaged slug and a more detailed history of what was done to the car and what transpired afterwards.

I suppose that it could have been under the 2% mark for the B/C reading, but still, it would have been nice to know in greater detail what was done to the car above before damage occured and to be able to educate fellow DIY stangers on what not to do.

Oh well, it was fun talking about a few possibilities.

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