Exhaust Stud Heli Coil Pulled Out, Wou is me, Help! Correction Time Sert came out Options

[913B]

So the continuing saga of fitting the SS heat exchangers continue. I somehow pulled out the heli coil repair on the exhaust stud. The coil measures 9.5mm OD.
I suppose I need to re-tap the hole with a step stud.

So what size step stud should I use ?? M8 to (M10 or M11) ?
Where would I find such a stud ?
Is it do-able, drilling and tapping from under the engine ?
How the heck am I going to keep the bit and tap straight and not F/up ?

Man it never ends with old cars...... (IMG:style_emoticons/default/ar15.gif)
Thanks in advance for everyones help !!!! I really appreciate it.
(IMG:style_emoticons/default/beerchug.gif)

[jcd914]

I have never used E-Z LOK inserts so I can't recommend or warn against them but I was looked at their site and found the drill/tap sizes.
If I was looking at pulling heads and having them rebuilt or trying to save 1 while on the car? I would look close at how bit the hole in the head is. An 8mm thread repair requires a 10.4mm drill and a 12mm tap, you might be able to get away with that and avoid the step stud.

Just a thought.

Jim

For 8mm x 1.25mm thread repair:
E-Z LOK Part No. 453-8
Internal Thread M8-1.25
External Thread M12-1.75
Length mm 12.5mm
Tap Drill Size 10.4mm
Tap Size M12-1.75
Minimum Full
Thread Depth 14.5mm
Drive Tool
Catalog No. 500-4

For 10mm x 1,5mm thread repair:
E-Z LOK Part No. 453-10
Internal Thread M10-1.5
External Thread M16-2.0
Length mm 17.0mm
Tap Drill Size 14.0mm
Tap Size M16-2.0
Minimum Full
Thread Depth 19.0mm
Drive Tool
Catalog No. 500-5