Exhaust Manifold stud broken

[Nickerz]

|Does anyone know what the thickness of the material around the studs are. As in how close are they to the water jacket. Will a m12 thread with an m8 thread insert be ok.?

[jimmyspeed]

well they often get helicoiled - which needs a larger tapped hole to fit the insert

why the jump from m8 - to m12?

[martauto]

With an internal thread of M8 x 1.25 the drill size is 8.3mm for helicoiling.

Mart.

[jimmyspeed]

less than i thought, but after tapping its in essence like tapping a standard m9/m10 hole

[biffer]

When a garage repaired a broken stud on my NO.1 cyl., they ended up with a timesert screwed into a larger timesert so there must be a fair bit of metal around them?

[martauto]

less than i thought, but after tapping its in essence like tapping a standard m9/m10 hole

It is indeed but the only other option is to circular mill the hole and weld an insert in which will not be cheep.

Mart.