A little helicoil advice

[billy-t]

Hi I have a QD 16 where the bottom spark-plug hole doesn’t thread normally, so I am thinking of installing a helicoil to avoid the thread giving way at in inopportune time.

So my question is is the size 14 mm 125 and what type of helicoil material should i use in this application? Stainless or something else.

Thanks for you assistance.

Bill

[david-bartlett]

Billy,

This topic comes up a lot. You do not want to use the regular Heli-coil spiral inserts for this. They make a better insert/kit just for spark plug holes. I have used it with great success.

http://www.google.com/imgres?imgurl=htt … PgodW58Pog

[Casey Lynn]

Ditto the Sav-A-Thread set up. Works like a champ.

[jerry-ahrens]

Same here. I’ve had one of those kits for 25 years now. I always cleaned everything well with carb cleaner then used Red Loktite on the insert. Never had a problem yet.

[johnny-infl]

X2 on Save-a-Thread. The first buy is the most costly b/c you gotta buy their special tool.
After that, almost nothing…… b/c then, you just go to NAPA and buy the insert size that
you need . . . not a box of those you will never use. 3/8" and 1/2" inserts should be in your tool box.
I also have used the High Temp Thread Lock with no issues in two years.

[johnyrude200]

If you use a regular helicoil, it can break off and cause pre-ignition. I posted a pic of a motor of mine that had the repair done improperly by a now out of business marina, and the evidence is pretty compelling to use the save-a-thread kit (I’ve used that many times and it works great). I do recommend removing the head during the install though to avoid metal shavings getting in the cylinder.

Not the type of job you want to screw up by taking the easy route!

[billy-t]

Thanks for the information, now i know which way to go. I definitely would pull the head for the repair.

thanks again

[Author]

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