Broken screw-thread for the sparkplug cilinder nr 5

[canvaspaul]

I track down the sound coming from the engine, at first I was looking for a vacuum-leak.
But it was no vacuum, some time ago I changed the spark plugs and checked the compression.
The spark plug number 5 was Very very hard to get out, At that time I cleared all the debris and pay no attention at the threat any more.

Can I repair this my self with a Thread kit, I presume the spark plug is M14, 1.25???


Ore is this beyond repair?

Gr Paul

 

[First Fox]

Yes, this can certainly be repaired. The best bet is to remove the head and have the spark plug hole drilled and tapped for a heli-coil insert. They make them for just such an occasion.

It is certainly possible however to do it without removing the head. I have done it while the head was on the car by using the proper drill and tap with plenty of grease on them to capture the cuttings, just work slowly. After the hole is tapped and you install the heli-coil, spray the combustion chamber with brake cleaner and blow it out with compressed air. After the loctite dries on the heli-coil, install a new spark plug and you are back in business. The whole thing should take a half an hour.

I think the kit for this was around 40 bucks back when I bought mine. Good luck to you!

 

[rbohm]

Yes, this can certainly be repaired. The best bet is to remove the head and have the spark plug hole drilled and tapped for a heli-coil insert. They make them for just such an occasion.

It is certainly possible however to do it without removing the head. I have done it while the head was on the car by using the proper drill and tap with plenty of grease on them to capture the cuttings, just work slowly. After the hole is tapped and you install the heli-coil, spray the combustion chamber with brake cleaner and blow it out with compressed air. After the loctite dries on the heli-coil, install a new spark plug and you are back in business. The whole thing should take a half an hour.

I think the kit for this was around 40 bucks back when I bought mine. Good luck to you!

8) perfect advice. if you choose to do this job, take your time and follow the helicoil instructions carefully. done right the job will last a long time. one thing you can do to make things last longer, even in the other cylinders that are still good, is when you install new plugs put a little antiseize compound on the plug threads. it prevents the threads from bonding to the head and makes it easier to remove the plugs next time.

 

[wsa111]

Excellent posts, however the threads are 18mm.
The existing threads look rough, but you could try to chase the threads with a 18mm spark plug tap.

 

[rbohm]

Excellent posts, however the threads are 18mm.
The existing threads look rough, but you could try to chase the threads with a 18mm spark plug tap.

that would certainly be the first thing to try, dont know why i didnt think of it.

 

[canvaspaul]

Thanks for the answers, so I have to find a repair-kit or ask my garage mechanic if he done this job more often. depending on the cost I make a choice DIY or the garage.
I'm a little bit nervous to tap into the iron casting head, will almost everything is finished I mes-up this one.

 

[First Fox]

yeah if you're not comfortable doing it, a mechanic will likely do it for you and I did several when I wrenched for a living. I distinctly remember removing a dogbone engine mount, rolling the engine forward with a cable come-a-long, and doing a cylinder on the BACK row of a 3.8 chevy V6 in a Lumina. The customer stripped the plug out himself trying to do a tune-up. I earned my money that day.

Don't feel bad for me, he paid dearly for it.

 

[Gene 64 2dr]

I may get really upset when I do a service call that turns into a pain in the butt but I always smile when making out the bill.