FILENAMES: Cylhead1.jpg Cylhead2.jpg Cylhead3.jpg Cylhead.gif DESCRIPTION: These are a pictures and a diagram about a cylinder head repair. Posted by Ted Edwards . The following description was provided: ================================================================= Stripped Sparkplug Hole Repair Ted Edwards 2001 Jul 26 Ted_E@bc.sympatico.ca Photos: CYLHEAD1.JPG, CYLHEAD2.JPG, CYLHEAD3.JPG Drawing: CYLHEAD.GIF My 1956 Johnson 30 hp outboard suffered from stripped threads in the spark plug hole. As can be seen in photo CYLHEAD1.JPG there is insufficient meat around the plug hole to use a helicoil since, without the boss, the head is only about 1/4" thick (if that) in that area. An attempt to TIG weld in a piece failed. Whether the failure was due to my lack of skill, the nature of the alloy or the effects of soaking in oil for 45 years, I know not. The repair was made with a specially made hollow aluminum "bolt" and nut as drawn in CYLHEAD.GIF and photo CYLHEAD3.JPG. Due to clearance requirements, a hex nut was not on. Instead the nut shown was made along with the special wrench shown with the parts. The insert was seated with aviation type gasket goo on the mating inside surfaces and Never-Seez on the threads and mating surface of the nut. The nut gets snugged up and the plug tightened to 15 ft.lbs. torque.