I don't know why there is so much controversy over how to properly install a heli-coil. but i cant find anywhere that has a straight guide to install the coils.

On youtube, i found some great videos, but some of them have contradicting steps. Some say to break off the little pin at the base, some say to leave it. one video says to put the coil in until it bottoms out, the other guide says to put it in just until it goes below the surface of the hole.

So what's the proper way to install a heli-coil?

Also, does anyone have a chat of the drill bits used to drill out the hole? Like lets say I'm using a 10x1.25 bolt (i believe that's what the exhaust stud sizes are on the 22re) and I have heli-coils made for the 10x1.25 bolt size. What sized drill bit would work best for this coil?

 

*bump* so nobody here knows how to properly use heli-coils?

 

So you just bought a pack of helicoils? You should have bought the kit, it comes with the correct tap and a tool to put them in, and possibly the correct drill bit. If not, it will tell you what size to use for the tap.

 

I have heli-coils from when I did the head job. When I did the head job, we borrowed the kit from the guy who was doing the valves for us.

We drilled the hole to clear all the crap out, and then we tapped the hole and made new threads for the heli-coil insert. We then too the coil and screwed it into the newly cleared hole. The heli-coil bottomed out, but when I went to torque the exhaust manifold back on it kept acting like it was still stripped/no heli-coil there. Bolt kept turning and turning. We even used some heat resistant thread locking compound.

So I got everything on as best as I could because I couldn't wait any longer. I needed the truck the next day.

So now I'm planning on a future piston ring job and when the head is off I'm going to fix all of the stripped holes. I'd like to know the best way to do it, because obviously I did something wrong.

 

I'll try to answer both your posts as best I can. How you install them, depends on what type of hole you have, and how deep the bolt goes into it.
If you have a closed end hole, you usually run the heli-coil in just about one thread below the surface of the hole, and I always knock out the tab (it usually has a break-away cut just for that purpose. This way it doesn't interfere with the bolt if it is longer than the heli-coil. Just remember to remove the tab piece from the hole. If the hole has an open bottom, then be careful when removing the tab, in case it could fall into something that might be damaged by it. If you have a deep set of threads you are trying to repair, you can use two heli-coils back to back, but you should be careful to make sure the first one in is deep enough to allow the second one room, and the tab needs to be removed. The heli-coil kit should tell you the exact size drill bit to use, or you can find the reference info online.

As for the problem you had, I don't know for sure what is going on. Are you sure you used the right size heli-coil thread for the bolt? If the heli-coil was installed correctly, and is the proper size, you can't spin it, and the bolt shouldn't just turn in it. Did you check the bolt to see if it's threads were good? If the bolt threads are bad, a heli-coil won't do much good. When properly installed, heli-coil threads are as good, or better than the original threads, especially if in aluminum.

I have used heli-coils a couple hundred times in both steel, and aluminum, and never had one fail yet.

 

I believe we did use the right heli-coil thread. It was with the kit that we borrowed from the mechanic. He might have confused the head prior to our borrowing it, but it seemed to fit and work.

The threads on the bolt were probably fine, as the bolt/stud was brand new. I just ordered a new set of exhaust studs from the dealer.

It was my first time and it appears we did everything right, so maybe it was just bad luck. When the head is off in a few months every stripped hole is going to be fixed.