head re-tapping?

[gmoney]

Ok i have had my car butchered at one shop with heli coils and that isnt holding very well. So would it be possible to tap the exhaust bolts that go into the block up to a 12mm bolt as opposed to the 10mm that it comes with. I would go with an 11mm but i cant find them anywere. so I figured a 12mm would be ok but wanted the peoples advice before i went and had another shop do it. thanks

 

[Squid699]

A buddy of mine couldn't find the proper size, so he used a larger size and said it works fine. Can't remember what size tho

 

[gmoney]

could you find out please?

 

[Squid699]

well apparently he told me wrong.......he used the US equivalent for the stock Metric size........wish he woulda gotten his story straight first. :3d_frown:

 

[gmoney]

damn! thanks anyway...wish someone could help me out.

 

[Bishop92t]

It is possible to go with a larger size, however you might find an english size easier to find and tap for. The other possibility would be to have someone build up the material with a TIG welder and tap into that.

 

[Allan_MA70]

heli-coils give a stronger threed in alloy then just a plain threed, i suggest you try new studs and nuts from toyota and use loctite super stud locker in the head

 

[Shawndude]

Stupid question, but can't you just helicoil a helicoil? I mean go the next size up on the cylinder holes, and then use the smaller original size coil inside of that?

There are some thick metal threaded inserts that should work, but I've never used those myself.

Something like this:
http://www.carrlane.com/Catalog/ind...006280B1713050245221E0107070F1A3C3B2853564755

 

[IJ.]

Shawn: The Helicoil in a Helicoil doesn't work as they use their own thread form for the OD and don't have a matching ID thread!

Keenserts would probably work.

 

[gmoney]

ill have the shop try the standard size first if that doesnt work ill have them check the heli coils maybe the shop i went to did them wrong.