The subject is a Toyota 2ZZ engine block
The bolt holes were cracked and then were welded making the holes out of line. The heil-coil will make this a simple fix.
The tools needed will be a Drill motor, the proper sized drill bit for the heil-coil kit, the heil-coil tap, install tool, and the heil-coil insert.
The Heil-coil kit being used is a 8 x1.25mm
The drill bit needed is 21/64
Install the drill bit into the drill motor, and drill the hole out.
Blow out the hole with compressed air
Next take the heil-coil tap
Tap the hole to its oversize.
*NOTE* Heil-Coil taps are an odd size.
On aluminum use a cutting fluid.
Keep the tap straight and square to the work piece.
Blow the hole out again
Now put the insert on the install tool
Now carefully screw the insert into the threads that were just cut, being careful not to apply too much force and skip a thread.
make sure to counter sink the top of the heil coil by a thread or two
Once the insert is in properly, snap the bottom tab off and blow it out of the hole.
B SVO,
What do you recommend doing if some one incorrecly installed a Heli-Coil. Specificaly, they didn't keep their drill and Heli-Coil strieght during the repair. Thanks for your "how-to" postings.
well that can be a tricky fix, depending on what metal it is, Cast Iron or Alum, what the job of the bolt is, Big diffrence if its a head bolt or some bracket bolt) and can the part be taken off the car easily.
some times, you can just try to redrill.retap the hole stright and install a new coil
other times the hole may have to be welded shut, and just start over
Thanks for the reply. The metal is cast Alu and it can be pulled off to place on a mill-drill for repair. It is more of a fit/seal problem, not much torque at 12 ft/lbs. Fixing someone elses mess-up always requries creative thinking. Thanks again.
Corvette Store
How to install a Heil-Coil
