Spark plug threadserts

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plrgpr
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Spark plug threadserts

Post by plrgpr »

Changed plugs in my 66 140 today (most of them anyway). #5 cyl had threadsert and the threadsert came out with plug. I was able to re-install the old plug with the threadsert still attached and it did tighten down so all is well for the time being. My question is, can I get a new threadsert from Clark’s, remove the old plug, with the threadsert still attached and simply thread in a new threadsert and install the new plug?
Gary Roberson
66 Vert 140 4-sp Corsa “clone”
66vairguy
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Re: Spark plug threadserts

Post by 66vairguy »

While I can only speculate, your problem is typical of an insert that was not properly installed. There are a couple mistakes that are made depending on the insert type.

Based on past comments from the corvaircenter forum the only long term fix for a pulled insert is to either weld up the spark plug hole and machine it (a specialized process that might cost more than a used replacement head). Some have tried an oversized spark plug insert, but this also has issues and requires careful work to install.

BTW Timesert's were the first to be approved by Ford for repairing aluminum spark plug holes. I've had good luck with their products. Again precise installation procedures have to be followed. https://www.timesert.com/

While Heli-Coils work well, they are not appropriate for a good spark plug hole repair.
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terribleted
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Re: Spark plug threadserts

Post by terribleted »

Timesert or their larger Bigsert for oversized holes are the way to go for sparkplug holes. Best of course is heliarc weld and machine a new plug hole and seat.

I have had this happen a number of times over the years (insert comes out with plug). A number of times I have simply found a way to remove the insert from the plug and then put it on my new plug and reinstall. I have had a couple friend/customers that have done this for years on their Corvairs. The key is to grasp the insert without doing any major thread damage. If you damage the threads much you will not be able to simply put it back in place without destroying the hole further. On one buddies car (never had or wanted to spend money on his daily driver and it needed to go every day to get him to work) we had this issue on #4 on his 140. we reused the insert for a couple plug changes over a few years. eventually it blew the plug and insert out. This time we tapped the hole out for an 18MM plug and installed a plug of the correct heat range and length but 18MM diameter. That engine went daily another couple years or more before it lost #1 cylinder from a dropped seat and fractured piston.
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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plrgpr
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Re: Spark plug threadserts

Post by plrgpr »

Thanks Ted. I thought about simply removing the insert from the plug but didn’t give it much effort as I was most certainly afraid of damaging the threads and be really up the creek. I just read-installed the old plug insert for the time being. I can’t think of a way to grip the insert w/o destroying the threads???
Gary Roberson
66 Vert 140 4-sp Corsa “clone”
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Re: Spark plug threadserts

Post by terribleted »

plrgpr wrote: Mon May 24, 2021 10:52 am Thanks Ted. I thought about simply removing the insert from the plug but didn’t give it much effort as I was most certainly afraid of damaging the threads and be really up the creek. I just read-installed the old plug insert for the time being. I can’t think of a way to grip the insert w/o destroying the threads???
Yes getting the insert off the existing plug can be problematic. I have had success at doing this a few times and no success a couple others. very slight thread damage can be fixed with a small triangle file, but, yeah if you badly mess the threads you are now fixing it a different way.
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia
joelsplace
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Re: Spark plug threadserts

Post by joelsplace »

Buy another insert if it won't come off or is ruined.
159 Corvairs, 5 Ultravans and counting
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corvair500
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Re: Spark plug threadserts

Post by corvair500 »

What is the number and brand of 18MM plug ?
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terribleted
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Re: Spark plug threadserts

Post by terribleted »

corvair500 wrote: Tue May 25, 2021 8:30 am What is the number and brand of 18MM plug ?
I do not remember what we used. Fit some Ford is all I remember.
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia
joelsplace
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Re: Spark plug threadserts

Post by joelsplace »

I think they are inline 6 Ford.
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nirvairna
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Re: Spark plug threadserts

Post by nirvairna »

I would call around to some auto machine shops and find one that has a "Big Sert" insert kit for a 14mm spark plug and have them install it for you. The kit is expensive for a one time use or hobbyist, it's about $350 USD.

If properly installed, it's a long lived repair.
joelsplace
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Re: Spark plug threadserts

Post by joelsplace »

http://www.timesert.com/html/5141S-457-NPN.pdf
Big Sert pictures and instructions.
159 Corvairs, 5 Ultravans and counting
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plrgpr
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Re: Spark plug threadserts

Post by plrgpr »

Ted, where did you get your timeserts? My plugs are NGK B5HSB
Gary Roberson
66 Vert 140 4-sp Corsa “clone”
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Re: Spark plug threadserts

Post by terribleted »

I ordered a Timesert kit from Clark's a number of years ago.
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia
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