Worn exhaust bolt threads

[salty_monk]

Tapping drill size is just under 7mm (17/24) I would think a 3/8 -16 or 3/8 24 tap would work but may require some drilling...

[BadBillyB]

Tapping drill size is just under 7mm (17/24) I would think a 3/8 -16 or 3/8 24 tap would work but may require some drilling...

Oops, I think you meant 17/64th's....This is the proper drill size for a 5/16" tap....If you put 8x1.25 heli-coils in, you need a 21/64th's drill bit. I personally would put heli-coils in, providing there is enough "meat" around the hole. Castings vary somewhat. Are you sure the threads way up in the hole are bad ???....I just rough measured the depth at around 1"....Thats pretty deep....Try a really long 8x1.25mm bolt and see if it gets tight when bottomed in the hole......Billy

[salty_monk]

You're right Billy... my typo, thanks