Removing heli-coil/time serts ?

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acarlson
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Location: Dahlonega, GA

Removing heli-coil/time serts ?

Post by acarlson »

A previous owner installed either a heli-coil or a time sert into one of the spark plug holes in my turbo. They did not do a particularly good job of the install. They only got it threaded about 2/3 of the way and left 2 full coils above the top of the hole. This of course meant that the spark plug could not seat correctly and did not reach the combustion chamber. I cut the 2 external coils off so the plug could thread all the way down but I still only have 60% threads available.

So, do I leave it that way (if it ain't broke, don't fix it) or is there some way to remove the insert without further damaging the head ? If I can get it out I'll replace it with a time sert from Clarks.

Oh, and the heads are off the block so I have easy access to both sides of the plug hole.

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
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b74eqcm
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Re: Removing heli-coil/time serts ?

Post by b74eqcm »

I am in the 'if it works, leave it alone' group. If you're catching enough threads that you can torque the plug correctly, and you have the correct penetration into the cylinder, I'd call it a win and move on.
Jim Thomas
Bethel, VT
63 Monza Coupe
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terribleted
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Re: Removing heli-coil/time serts ?

Post by terribleted »

With the heads off it would be best to get a good repair on that. Too bad you cut off the heli-coil end, they come out pretty easy if you grab t he sticking out end and twist (not so easily if they are properly installed sub-flush), although if you can get hold of the end of the threads you may be able to pull twist it out still. Is there enough material left for proper timesert install? I would likely consult a machine shop that does a lot more of these repairs than I to determine the best solution. I bet Kent Ford could advise as to whether an insert is a good option on your head or whether it might need heliarc welding and drilling?
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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Located in Snellville, Georgia
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acarlson
Posts: 454
Joined: Wed Nov 02, 2016 5:54 pm
Location: Dahlonega, GA

Re: Removing heli-coil/time serts ?

Post by acarlson »

I haven't contacted Kent yet. I'm heading out of town for a week (going to the Convict Rodeo at the LA State Penitentiary) so I figured I'd pick this up again when I get back. Kent's shop is only 2 miles from my house so I may take my heads over there late next week and get his opinion on this.
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
66vairguy
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Re: Removing heli-coil/time serts ?

Post by 66vairguy »

Let Ken look at it. A Heli-Coil has it's place, but I would not use a Heli-Coil for a spark plug hole repair - not suitable. The Time-Sert, or a similar design, is the preferred fix.
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