re-tapping my headers/block

[Shnizzle]

previous owner stripped the header bolts and i need to re-tap them. I have a 2G exhaust manifold and i was just wondering if anyone knows how much room i have to play with. im re-drilling the threads in the headers as well as the block itself. I obviously dont want to damage the head, because then the motor is DONEZO. does anyone know what kind of room im dealing with here?

 

[Bud92gsx]

Why not just helicoil the hole?

 

[Shnizzle]

Why not just helicoil the hole?

never heard of that.What is it?
2 studs are stripped and the other is broken off in the block, by the way so its kind of important to get it done right i have exhaust/boost leaks right at the headers!!

 

[taz4432]

Helicoils are a thread repair tool.

How it works is you drill out the hole (to eliminate all previous threads), use the special-sized tap that comes in the Helicoil kit specific to the size of thread you need (M8*1.25 for all holes on a 6-bolt head, or M8*1.25 for the small studs and M10*1.25 for the two big studs on a 7-bolt head) and then thread in the insert which creates new threads of the desired pitch. I just finished drilling out and helicoiling two head studs with the head on the car a few weeks ago. Most of the holes there is enough access with the turbo/rad/etc. out of the way to do it with the head on the car. The only thing you MUST make sure of is to centre punch the broken stud(s) so that when you drill them out you keep the holes concentric/centred. This is VERY critical.

Even if there is no broken stud in the hole and it's just stripped out, make sure you drill perfectly aligned!

http://www.helicoil.in/helicoil.htm

 

[BogusSVO]

The Heli-coil will work fine.

What stud is broken off in the block?

 

[Shnizzle]

Helicoils are a thread repair tool.

How it works is you drill out the hole (to eliminate all previous threads), use the special-sized tap that comes in the Helicoil kit specific to the size of thread you need (M8*1.25 for all holes on a 6-bolt head, or M8*1.25 for the small studs and M10*1.25 for the two big studs on a 7-bolt head) and then thread in the insert which creates new threads of the desired pitch. I just finished drilling out and helicoiling two head studs with the head on the car a few weeks ago. Most of the holes there is enough access with the turbo/rad/etc. out of the way to do it with the head on the car. The only thing you MUST make sure of is to centre punch the broken stud(s) so that when you drill them out you keep the holes concentric/centred. This is VERY critical.

Even if there is no broken stud in the hole and it's just stripped out, make sure you drill perfectly aligned!

Helicoil | Helicoil Insert | Helicoil Inserts | Helicoil kit | Helicoil Thread Repair Kits | Heli-Coil | Helicoil India | Wire Thread Insert | Helicoil Manufacturers | Helicoil Suppler

okay sounds pretty similar to tapping the hole. And the thing is, previous owner already retapped/helicoiled the holes so i dont know how much extra room i have to play with. The holes are way bigger than the stock stud size.

The Heli-coil will work fine.

What stud is broken off in the block?

the top left is broken off, bottom left stripped and mid bottom right stripped

not to mention he replaced some studs with BOLTS going into the block!! eww.

 

[Bud92gsx]

http://www.dsmtuners.com/forums/articles-miscellaneous/457207-broken-exhaust-stud-repair.html

http://www.dsmtuners.com/forums/articles-miscellaneous/361131-how-install-heil-coil.html