sudden exhaust leak...need helicoil sizes

[Guest]

well just my luck im crusing along...come to a stop an take off an ill be damned if i didnt hear a nasty exhaust leak...

ome to find out a bolt is missing and just stripped out trying to put one in..

surley someone knows the right size heli coil..if not ill head to napa in the mornin with a spare bolt...

(has4-1 headerz)

[7981GS]

If it is a head bolt, they can be tapped about 20 mm deeper.
Just tap and install a longer bolt.

Eric

[gs850cafe]

If it is a head bolt, they can be tapped about 20 mm deeper.
Just tap and install a longer bolt.

Eric

oh cool ill try that first...is it possible to go to far?

[7981GS]

oh cool ill try that first...is it possible to go to far?

You are NOT going to be drilling any deeper than the existing blind hole.
You ARE going to be tapping to the bottom of that blind hole.
Buy a bottoming tap ( they place more threads, deeper, into an existing tapped hole) 8 mm X 1.0 pitch (IIRC.)

Eric

[gs850cafe]

You are NOT going to be drilling any deeper than the existing blind hole.
You ARE going to be tapping to the bottom of that blind hole.
Buy a bottoming tap ( they place more threads, deeper, into an existing tapped hole) 8 mm X 1.0 pitch (IIRC.)

Eric

my bad im really tired..didnt read it clealy..thanks again ill post result tommorow if i get to it..thanks

[Steve]

... 8 mm X 1.0 pitch (IIRC.)

Eric

Are those bolts the fine 1.0 pitch or the standard 1.25?

I'm thinking that they don't usually use fine threads into aluminum, so are probably 1.25 pitch.

Anybody else confirm this either way?

.

[7981GS]

Steve is correct. Standard pitch (coarse threads)

Eric

[gs850cafe]

Are those bolts the fine 1.0 pitch or the standard 1.25?

I'm thinking that they don't usually use fine threads into aluminum, so are probably 1.25 pitch.

Anybody else confirm this either way?

.

correct pitch...picked one up from napa for 4 bux...but they was already threaded...helicoil is my last option right?(38 damn bux)

[EvilEnfield]

No, you can get an exhaust stud one size larger, M10 over here, file down the pipe side of it then run an M8 die over that side, then tap out the the hole to M10, my thinking was that if that failed then at least there'd still be some meat for a helicoil.

[hampshirehog]

No, you can get an exhaust stud one size larger, M10 over here, file down the pipe side of it then run an M8 die over that side, then tap out the the hole to M10, my thinking was that if that failed then at least there'd still be some meat for a helicoil.

No need to jump straight to M10 - the old trick is to use imperial studs. 3/8 UNF stud is roughly equivalent to 9mm fine thread.