How To Use A Helicoil Thread Repair Kit

You are just about finished with your most recent maintenance project, one more than commodities to tighten and…. dang information technology, wouldn't you know the threads just blew out in the cylinder head. Y'all remove the bolt and it is coated with aluminum, which means that the threads in the head are stripped, non the bolt. At present you are in for work. Stripped threads are rarely any fun, but they are a part of working on vehicles. If you only lost the top one or two threads, you can get by, merely if information technology goes any deeper than that, you need to restore it. That's when knowing how to install a Helicoil insert comes in handy.

Fixing Stripped Threads

The components of a Helicoil kit are the inserts, a special tap and the installer too. You need to provide the drill bit for most kits. — The components of a Helicoil kit are the inserts, a special tap and the installer too. You lot need to provide the drill scrap for near kits.

In this instance, a tap is non going to cut it, the threads are wasted and while yous might be able to get a little bite with a tap, it won't terminal. The best bet is to repair the threads with a HeliCoil insert. A HeliCoil is a coiled threaded insert that installs into the part, providing the right threads for the original fastener. There are several types of thread repair inserts, only the near common is the tanged insert. These inserts have a diamond-shaped cantankerous section with 60-degree threads on the inside and specially designed threads on the outer ring, which grips the walls of the hole.

HeliCoil Insert Types

The HeliCoil insert itself has special threads designed to grab the walls of the part, and the tang is there to help drive the insert into place. — The HeliCoil insert itself has special threads designed to catch the walls of the part, and the tang is there to help drive the insert into place.

Gratis running inserts are fully rounded inserts that are slightly larger than the hole they install in. When installed, they grip the walls of the hole through the spring-loaded action. This allows the fastener to easily install and be removed as well. These do not require any special staking or locking. Screw locking inserts have a serial of flat spots on the spiral threads, which put pressure level on the fastener, holding it in tight. They are reusable, and however maintain their grip on the fastener.

How To Install A HeliCoil Insert

Installing a HeliCoil insert requires drilling out the original hole to lucifer the new gyre, borer the hole for the coil, installation, and tang removal. You can purchase the inserts individually or in kits. You lot need a master kit for the size of threads you are working with if you lot do not accept a tap and die gear up.

Pro Tip – The proper installation depth of a HeliCoil insert is ¼-ane/2 turn beneath the meridian of the original hole.

Remove the fastener from the hole. Audit the hole and brand sure the threads are damaged. Use a little brake cleaner or compressed air to blow out the hole (remember to wearable eye protection).

The original hole in this aluminum windshield frame is not stripped, but it is not far from it. In order to stop a major problem from occurring, we decided to fix it with a HeliCoil. — The original hole in this aluminum windshield frame is not stripped, but it is not far from information technology. In order to stop a major problem from occurring, we decided to fix information technology with a HeliCoil.

Using the correct size drill fleck for the insert, drill out the hole. Make sure you drill to the end of the pigsty, but non deeper than necessary. You don't want to punch through and impairment something on the other side (like a water jacket or wiring harness).

The 3/8" kit we are using requires a 25/64" drill bit. We drilled out the hole, while ensuring that it was drilled square. — The iii/8″ kit we are using requires a 25/64″ drill bit. We drilled out the hole, while ensuring that it was drilled square.

Thread the new hole with the correct tap for the size of insert you have. These taps are not standard 60 degree thread taps, they are specific STI (Screw Thread Insert) tools. Unlike a standard tap, the threads are the aforementioned, simply the diameter is slightly larger, yielding more grip for the insert.

Once the hole is cleaned out, the supplied tap was used to cut the new threads for the insert.

Here is where the process alters depending on the thread pitch of your fastener, coarse or fine.

Coarse thread – Using the installation tool , mount the HeliCoil insert to the tool, rotate the insert until the tang mates with the drive notch on the tool. Thread the insert into the hole to the proper depth. Then remove the installation tool.

We are using a coarse thread insert, so the insert was installed onto the installer tool until the tang hit the stop. — We are using a coarse thread insert, and so the insert was installed onto the installation tool until the tang hit the end.

Using the handle for the tap, we installed the insert. You can use a light thread locker, but it is not necessary, the insert is designed to hold itself in place. — Using the handle for the tap, we installed the insert. You can utilise a light thread locker, merely information technology is not necessary, the insert is designed to hold itself in identify.

Fine thread – Install the HeliCoil insert into the pre-coil tool. This tool compresses the insert to the right size. Thread the install tool into the insert within the pre-coil body. Spin the installation tool until it is fully threaded.

Hold the pre-coiled assembly to the hole being repaired. Thread the installer tool then that the insert threads out of the pre-coiler and threads directly into the repaired hole until it reaches the proper depth and remove the installer tool.

At this point, the insert is installed, but the chore is not over. For all tanged inserts, the tang must exist removed. Using a dial that fits snugly into the insert, place the punch into the insert until information technology reaches the tang. Hit the punch with a hammer. This should popular the tang off. Use a magnet or tweezers to remove the tang.

Here you can see the tang. If it is at the bottom of the hole, you can leave it, but it is best to remove it in all cases. — Here you tin run across the tang. If it is at the bottom of the hole, you can leave it, but information technology is all-time to remove information technology in all cases.

Using a non-tapered punch, the tang is knocked off. It should only take one or two pops. — Using a not-tapered dial, the tang is knocked off. It should merely take one or ii pops.

The tang can be removed with a pair of needle-nose pliers. — The tang tin can be removed with a pair of needle-nose pliers.

HeliCoils do not require thread sealants or thread locker in order retain the insert, but if yous experience the need to use sealant or thread locker, a light coating may be practical to the outer threads, making sure the inner threads are make clean. Once installed, HeliCoil inserts are very reliable and trustworthy. They have been used for high-performance applications nether high stress, they perform very well in most situations.

Check out all the tools & equipment available on NAPA Online or trust 1 of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more than data on HeliCoil thread inserts, chat with a knowledgeable expert at your local NAPA AUTO PARTS store .

Jefferson Bryant View All

A life-long gearhead, Jefferson Bryant spends more time in the store than anywhere else. His career began in the motorcar audio industry as a shop managing director, eventually working his manner into a position at Rockford Fosgate equally a product designer. In 2003, he began writing tech articles for magazines, and has been working every bit an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin', Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Clay Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.