spark plug heli coil

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dick2256
Posts: 117
Joined: Wed Dec 10, 2014 10:05 am

spark plug heli coil

Post by dick2256 »

I installed a heli coil in my 1965 corvair and it seems to be stripped out now
can I rethread with a larger coil that is 14mm for the plug or is there a better way to repair this
with out replacing the head?
Wagon Master
Posts: 474
Joined: Thu Jul 28, 2011 6:36 pm

Re: spark plug heli coil

Post by Wagon Master »

What? Reread what you posted. Is that what you meant to say?
martyscarr
Posts: 319
Joined: Sun Dec 13, 2009 10:33 am
Location: Eugene, OR

Re: spark plug heli coil

Post by martyscarr »

If the hole is not over .660" it can be repaired with an insert called "big sert" made by Timesert. http://www.timesert.com/html/bigsert_sparkplug.html They have inserts available in both steel and aluminum. I have used these with good results. The kit is rather expensive, you might be able to find a machine shop that has one.

HTH
Marty Scarr
dick2256
Posts: 117
Joined: Wed Dec 10, 2014 10:05 am

Re: spark plug heli coil

Post by dick2256 »

I am not sure what you are saying
what I am asking about was answered by martyscarr
66vairguy
Posts: 4531
Joined: Tue Dec 21, 2010 3:44 pm

Re: spark plug heli coil

Post by 66vairguy »

Helicoils are not the best choice for spark plug hole thread repairs as they can come out with the plug.

As Marty said the "Timesert" is the one of the best fixes IF done correctly. If your are in a club someone may already have the kit. Sometimes FLAPS rent out the kits.

Go look at some demo videos on how to install Timeserts
dick2256
Posts: 117
Joined: Wed Dec 10, 2014 10:05 am

Re: spark plug heli coil

Post by dick2256 »

I have another head that is on a different engine an will pull it off and check the valves and valve guides
I will probably clean it up and use it I think the guy that had that car had just overhauled it and drove it 800 miles and fried the number 5 piston
so the head should be like new. at least none of the plug holes are stripped out.
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