Holding a spark plug from a Ford 5.4 (late model), he stated his shop uses the following procedure:

1. Remove COPS
2. Loosen the spark plugs 1/8 of a turn max
3. Reinstall COPS
4. Start engine and shut off immediately
5. Remove COPS & plugs

His theory.....

by loosening the plugs then firing the engine, this burns the carbon off the end of the plugs that can get on the threads and of course cause the broken plug.

Ok, Since I can't picture in my mind how this would work, unless by loosening the plugs a tad allows the "fire" to travel up, burning off the carbon.

Ok techs- your thoughts? has anybody heard of this?

 

hmm!! And no soaking involved? I hope someone doing plugs in the future would try this.

 

Are you sure you got his theory right because it does not make sense. The threads are above the seal. They do not cause breakage. The nose (ground shield) is below the seal. That is where the carbon builds-up

 

Because there are too many threads in the cylinder that get built up with carbon, I would think it would be too difficult to remove the plugs in that way. I did see the Motor week episode, and Pat does make sense, but the 5.4 plugs are a little bit more unique, IMO.

 

its not the threads that are the problem, its the center of the plug sticks out like 1in past the threads into the cylinder. i have been told that a 3/8 impact removes them well with very few breaking but i have not done it myself.

 

You are correct about that for sure, but the carbon-ed up threads are ofter the double whammy too.

 

Has anyone used the Lisle's LIS 65600 removal tool? I'm a former SMT and been out of the loop for 3.5 yrs. Any tips would be helpful.

 

These threads do not get any carbon on them. The threads have nothing to do with the breakage. The threads are above the seal. The traditional sparkplug design has the seal above the threads so those threads do build-up with carbon.

 

I haven't seen the theory but my guess is: by opening the seal and starting the engine, the high temperature combustion gases now have a path to flow past the shield, past the seal, past the threads, and to the outside. The high temperature gases should burn the carbon off.
With the plug tightened, the seal stops flow so that region does not get hot enough to burn the carbon off so it collects.

 

here's a link
MotorWeek: Auto Basics: Goss' Garage

His discussion of the threads is incorrect - I wonder if he does not know that his explanation is wrong, or if he is simply taking some "liberty" in his explanation.

It doesn't hurt to start the engine as it may help to blow away some of the fractured carbon buildup but I would not trust it completely. I suggest adding solvent if the removal torque goes above 25 ft-lbs. And work it back and forth as he suggests. Some where on this site it has been measured that the ground shield will break off at about 32 ft-lbs. You likely will need to exceed this torque when doing the "no more than 1/8 turn" loosening since the installation torque is close to 32 ft-lbs but do not exceed after that.

 

ok- I'm glad that I'm not lossing my mind with regards to a little common sense!