How to install a Heli-Coil
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How to install a Heli-Coil
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 heli-coil kit, the heli-coil tap, install tool, and the heli-coil insert.
![](https://www.miataturbo.net/attachments/engine-performance-56/63543-how-install-heli-coil-dscf4384.jpg?dateline=1357315301)
The Heli-coil kit being used is a 8 x1.25mm
The drill bit needed is 21/64
![](https://www.miataturbo.net/attachments/engine-performance-56/63544-how-install-heli-coil-dscf4383.jpg?dateline=1357315301)
Install the drill bit into the drill motor, and drill the hole out.
![](https://www.miataturbo.net/attachments/engine-performance-56/63545-how-install-heli-coil-dscf4385.jpg?dateline=1357315301)
Blow out the hole with compressed air
![](https://www.miataturbo.net/attachments/engine-performance-56/63546-how-install-heli-coil-dscf4389.jpg?dateline=1357315301)
Next take the heil-coil tap
![](https://www.miataturbo.net/attachments/engine-performance-56/63547-how-install-heli-coil-dscf4386.jpg?dateline=1357315301)
Tap the hole to its oversize.
*NOTE* Heli-Coil taps are an odd size.
On aluminum use a cutting fluid.
![](https://www.miataturbo.net/attachments/engine-performance-56/63548-how-install-heli-coil-dscf4388.jpg?dateline=1357315301)
Keep the tap straight and square to the work piece.
Blow the hole out again
Now put the insert on the install tool
![](https://www.miataturbo.net/attachments/engine-performance-56/63549-how-install-heli-coil-dscf4393.jpg?dateline=1357315301)
Now carefully screw the insert into the threads that were just cut, being careful not to apply too much force and skip a thread.
![](https://www.miataturbo.net/attachments/engine-performance-56/63550-how-install-heli-coil-dscf4395.jpg?dateline=1357315301)
Make sure to counter sink the top of the heil coil by a thread or two
![](https://www.miataturbo.net/attachments/engine-performance-56/63551-how-install-heli-coil-dscf4397.jpg?dateline=1357315301)
Once the insert is in properly, snap the bottom tab off and blow it out of the hole.
![](https://www.miataturbo.net/attachments/engine-performance-56/63552-how-install-heli-coil-dscf4390.jpg?dateline=1357315301)
All done and ready to have the part bolted back!
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 heli-coil kit, the heli-coil tap, install tool, and the heli-coil insert.
![](https://www.miataturbo.net/attachments/engine-performance-56/63543-how-install-heli-coil-dscf4384.jpg?dateline=1357315301)
The Heli-coil kit being used is a 8 x1.25mm
The drill bit needed is 21/64
![](https://www.miataturbo.net/attachments/engine-performance-56/63544-how-install-heli-coil-dscf4383.jpg?dateline=1357315301)
Install the drill bit into the drill motor, and drill the hole out.
![](https://www.miataturbo.net/attachments/engine-performance-56/63545-how-install-heli-coil-dscf4385.jpg?dateline=1357315301)
Blow out the hole with compressed air
![](https://www.miataturbo.net/attachments/engine-performance-56/63546-how-install-heli-coil-dscf4389.jpg?dateline=1357315301)
Next take the heil-coil tap
![](https://www.miataturbo.net/attachments/engine-performance-56/63547-how-install-heli-coil-dscf4386.jpg?dateline=1357315301)
Tap the hole to its oversize.
*NOTE* Heli-Coil taps are an odd size.
On aluminum use a cutting fluid.
![](https://www.miataturbo.net/attachments/engine-performance-56/63548-how-install-heli-coil-dscf4388.jpg?dateline=1357315301)
Keep the tap straight and square to the work piece.
Blow the hole out again
Now put the insert on the install tool
![](https://www.miataturbo.net/attachments/engine-performance-56/63549-how-install-heli-coil-dscf4393.jpg?dateline=1357315301)
Now carefully screw the insert into the threads that were just cut, being careful not to apply too much force and skip a thread.
![](https://www.miataturbo.net/attachments/engine-performance-56/63550-how-install-heli-coil-dscf4395.jpg?dateline=1357315301)
Make sure to counter sink the top of the heil coil by a thread or two
![](https://www.miataturbo.net/attachments/engine-performance-56/63551-how-install-heli-coil-dscf4397.jpg?dateline=1357315301)
Once the insert is in properly, snap the bottom tab off and blow it out of the hole.
![](https://www.miataturbo.net/attachments/engine-performance-56/63552-how-install-heli-coil-dscf4390.jpg?dateline=1357315301)
All done and ready to have the part bolted back!
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