1) I have done this job dozens of times.
• If the plug blew out, then most of the threads are gone and THERE ARE NOT ENOUGH THREADS remaining to engage.
• In your case, the cyl head has to come off so that you can tap from the INSIDE going in the reverse direction.
• Due to the need for the spark plug sealing ring to lie FLAT against the plug surface you MUST follow the old threads. Thus you need to go extremely slow in order to go straight.
• The only way you can go slow AND straight is to use a T-handle, so that you don't push the tap off course due to uneven loading of the tap handle. Bert is correct, DO NOT use a ratchet. And DO NOT use a drill motor.
• I highly suggest you buy a 14mm spark plug repair kit from Heli-Coil. Spend the money and buy the real thing because they work the best. They come with a 2-diameter tap (starter and finisher) to give you the best chance at success. The solid inserts always back out. Solid inserts are trash.
• Tapping is done with LOTS of lubrication. The best results are obtained by cutting in 1 turn, then reversing by at least 1/2 turn. This breaks the chip... which is necessary due to the design of the tap itself. Coming all the way back out, blowing out all the chips with compressed air, and then applying all new lubricant is the best method. This back and forth is why a drill motor is NOT recommended.
• Install the Heli-Coil from the outside. The coil end should end up below flush. Again lots of lubrication.
2) A stripped plug hole is merely a SYMPTOM of another problem: Incorrect technique.
A stripped plug hole is COMPLETELY avoidable by adding one simple step. Cyl heads are typically aluminum. Spark plugs are typically steel. Steel and aluminum REALLY do not like each other, especially in high-heat situations. That is the very nature of the 2 materials. So the installer must find a way to separate the 2 materials. The correct technique is to add a compound to the spark plug threads BEFORE installation that keeps them separated. Products like Never-Seeze which add nickel or copper work the very best. But, simply dabbing 2 drops of motor oil from the dip stick onto the threads is better than nothing. The oil bakes on and forms a patina, which is strong enough to give the needed lubrication and more importantly, the separation.
If you ever see a mechanic install a spark plug without so much as 2 drops of motor oil, you'll know that person is an idiot. Lubricating spark plug threads is Mechanic 101. It's basic information. Stuff you learn the first week on the job.
Bottom Line: You're probably doing this entire job for the lack of 2 drops of motor oil.
• If the plug blew out, then most of the threads are gone and THERE ARE NOT ENOUGH THREADS remaining to engage.
• In your case, the cyl head has to come off so that you can tap from the INSIDE going in the reverse direction.
• Due to the need for the spark plug sealing ring to lie FLAT against the plug surface you MUST follow the old threads. Thus you need to go extremely slow in order to go straight.
• The only way you can go slow AND straight is to use a T-handle, so that you don't push the tap off course due to uneven loading of the tap handle. Bert is correct, DO NOT use a ratchet. And DO NOT use a drill motor.
• I highly suggest you buy a 14mm spark plug repair kit from Heli-Coil. Spend the money and buy the real thing because they work the best. They come with a 2-diameter tap (starter and finisher) to give you the best chance at success. The solid inserts always back out. Solid inserts are trash.
• Tapping is done with LOTS of lubrication. The best results are obtained by cutting in 1 turn, then reversing by at least 1/2 turn. This breaks the chip... which is necessary due to the design of the tap itself. Coming all the way back out, blowing out all the chips with compressed air, and then applying all new lubricant is the best method. This back and forth is why a drill motor is NOT recommended.
• Install the Heli-Coil from the outside. The coil end should end up below flush. Again lots of lubrication.
2) A stripped plug hole is merely a SYMPTOM of another problem: Incorrect technique.
A stripped plug hole is COMPLETELY avoidable by adding one simple step. Cyl heads are typically aluminum. Spark plugs are typically steel. Steel and aluminum REALLY do not like each other, especially in high-heat situations. That is the very nature of the 2 materials. So the installer must find a way to separate the 2 materials. The correct technique is to add a compound to the spark plug threads BEFORE installation that keeps them separated. Products like Never-Seeze which add nickel or copper work the very best. But, simply dabbing 2 drops of motor oil from the dip stick onto the threads is better than nothing. The oil bakes on and forms a patina, which is strong enough to give the needed lubrication and more importantly, the separation.
If you ever see a mechanic install a spark plug without so much as 2 drops of motor oil, you'll know that person is an idiot. Lubricating spark plug threads is Mechanic 101. It's basic information. Stuff you learn the first week on the job.
Bottom Line: You're probably doing this entire job for the lack of 2 drops of motor oil.
