Repairing a stripped out spark plug hole

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Repairing a stripped out spark plug hole

Postby Larry Jowdy » Sun Jul 19, 2009 9:00 am

There are basically two different situations, the first is damaged threads but still useable. If this is the case, you can buy a spark plug thread chaser. Much like a tap that re-aligns the threads and makes them useable.

The second requires more work to repair:

If you have the unfortuante ixperience of having a spark plug \"pop\" loose from it's threads then basically you're screwed (but only a little bit). Life isn't over as you know it, it can be repaired

If it popped out then the threads in the cylinder head are kaput.... But, it doesn't require a total disassembly of the head to make a repair. A kit is available that allows you to thread the cylinder head then install a collar similar to a heli-coil except it's a solid piece. That device is then screwed onto the spark plug and the plug and heli-coil like device is then screwed into the head. (use loctite) Once the device is securely fastened to the head, remove the plug and allow the loctite to dry.

Usually takes about 30 minutes to make the repair and it will be a lot easier if you remove the intake manifold. Since you don't have to drill out the existing hole, the metal shaving are very small and for the most part, won't damage the engine.

I've repaired over 15 cylinder heads using this method with great success.

http://www.popularmechanics.com/automot ... 12608.html

http://www.globalspec.com/FeaturedProdu ... read_Rep...
Larry Jowdy
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