How to chase helicoiled threads?

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Trevor B

Trevor B

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Cleaning up some stock heads off a 360 and chasing all the threads. Both of the end holes that go into the water jacket had been helicoiled but so dirty I didn't even notice until I got the 5/16 chasing tap into one of them (got a few turns in, felt pressure, stopped, and tried to remove). The helicoil started to unravel so I pulled it out. Is there a way to chase the other hole, which is filthy, without destroying the helicoil?
 
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Have you ever used these?, they are WAY better than helicoil repairs, you drill then tap to the specific size to the threaded insert ( that info is supplied with the insert ), then simply turn them in and then strike down the four small pins with a punch, not only did you fix it but it will NEVER come back out, I have a marine repair shop we use these all the time I stopped using helicoils years ago.
 
Go to your local hunting supply store and buy a bunch of gun cleaning brushes, I get them in SS and they hold up great, put them in a cordless drill and run them in rev and run out.
 
mopar56 said:
View attachment 1715055025Have you ever used these?, they are WAY better than helicoil repairs, you drill then tap to the specific size to the threaded insert ( that info is supplied with the insert ), then simply turn them in and then strike down the four small pins with a punch, not only did you fix it but it will NEVER come back out, I have a marine repair shop we use these all the time I stopped using helicoils years ago.
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What are those things called? I have the same problem with my driver side header bolts going into the water jacket - the helicoil there is not holding and getting exhaust leak... those look way more reliable
 
Don't mind my previous question. When searching for them I had put "like helicoil" with my search terms and all it brought up was helicoils... soon as I took that out it brought up key locking threaded inserts. Thanks!
 
mopar56 said:
View attachment 1715055025Have you ever used these?, they are WAY better than helicoil repairs, you drill then tap to the specific size to the threaded insert ( that info is supplied with the insert ), then simply turn them in and then strike down the four small pins with a punch, not only did you fix it but it will NEVER come back out, I have a marine repair shop we use these all the time I stopped using helicoils years ago.
Click to expand...

Darticon said:
What are those things called? I have the same problem with my driver side header bolts going into the water jacket - the helicoil there is not holding and getting exhaust leak... those look way more reliable
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Those are called keenserts. Make sure you have enough material around your hole for them.

And they leak like bitches if you use them backed to a water jacket. Because of their design, It's tough to keep sealant on the threads.

You have to Dremel them out. They're badass but the exterior thread usually falls outside the gasket sealing areas. If it goes to water, use caution
 
mopar56 said:
View attachment 1715055025Have you ever used these?, they are WAY better than helicoil repairs, you drill then tap to the specific size to the threaded insert ( that info is supplied with the insert ), then simply turn them in and then strike down the four small pins with a punch, not only did you fix it but it will NEVER come back out, I have a marine repair shop we use these all the time I stopped using helicoils years ago.
Click to expand...

I work for a NASA contractor and we use this "Keensert" style exclusively. For an airtight (or watertight) seal, they are installed with a little epoxy applied to the external threads.
 
Thanks All -
I think I'll just pull the helicoil out and put another one in as I have 5/16 on hand (after chasing the hole with the correct tap). Definitely going to need some sealant in there, but that's always the case for those holes. The threaded inserts look pretty cool and I'll have to try some in the future. Pricey though.
 
KosmicKuda said:
I work for a NASA contractor and we use this "Keensert" style exclusively. For an airtight (or watertight) seal, they are installed with a little epoxy applied to the external threads.
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That's interesting that you can get them to seal. We had issues with leakage through the little pins, on the keensert side. Awesome for plastics though!
 
Trevor B said:
Thanks All -
I think I'll just pull the helicoil out and put another one in as I have 5/16 on hand (after chasing the hole with the correct tap). Definitely going to need some sealant in there, but that's always the case for those holes. The threaded inserts look pretty cool and I'll have to try some in the future. Pricey though.
Click to expand...

OOP'S sorry I missed these last post I have not been on here for a day or two, not sure where you pricing them from but if you already have the drill and tap, they are actually quite cheap even up here in Canada where we pay three times for almost everything you guys do they are only about 2 bucks each at my local fastener store, maybe you are looking on line, if you have a specialty fastener store near you they will have them, maybe by a different name, I think they call them " griprite's or grip inserts" at the store I get them from, also a bit of sealer on the thread takes care of any leaks I use them on outboard gearcases all the time that are always under water...no leaks!
 
Thanks for the tip. Already pulled, chased, and reinstalled a new helicoil. But will check out in the future.
 
Shouldn't be using a tap to chase holes...... should use a proper thread chaser. Difderent taps, especially cheaper ones, will remove more material resulting in a sloppy hole... no one likes a sloppy hole, LOL. Thread chasers do not cut, they just clean and should work on a work on a helicoil without grabbing it.
 
I never use those 4 little pins. I use a little green loctite instead . If you strip out a keensert you'll pull your hair out fighting with those 4 hardened stakes. Just heat the insert up unscrew it and put in a new one. Loctite doesn't exist at 900 deg.
 
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