Retired Wrencher 5,459 #1 Posted December 2, 2023 I have a head off a K181 been out of service for a while.The spark plug hole is strip out. Ben reading up on ways to tap and helicoil the head but can’t find what size to use meaning tap size and helicoil size . Any info would be helpful. I believe the spark plug is 14mm. Share this post Link to post Share on other sites
rmaynard 15,474 #2 Posted December 2, 2023 I have done several succesfully. The size is 14mm x 1.5 https://shop.advanceautoparts.com/p/heli-coil-spark-plug-sav-a-thread-master-set-thread-repair-kit-m14x125-5334-14/9010505-P?c3ch=PLA&c3nid=9010505-P&adtype=pla_with_promotion&product_channel=online&store_code=&&&&&gad_source=1&gclid=Cj0KCQiAyKurBhD5ARIsALamXaEIvlzeT0boeiIgFFGqKG2v0PK5s7Ezg3O49lfJKM3fGt-qM2fqDQcaAusNEALw_wcB&gclsrc=aw.ds 3 Share this post Link to post Share on other sites
ri702bill 8,324 #3 Posted December 2, 2023 Buy the "kit", not just the single Helicoil. A tad pricey, but comes with the proper drill, special tap, a few Helicoils, and the tool to install it. You need to break off the internal drive tang at the bottom when done. Best part - you will have everything to do a few more..... 5 Share this post Link to post Share on other sites
Retired Wrencher 5,459 #4 Posted December 2, 2023 32 minutes ago, rmaynard said: I have done several succesfully. The size is 14mm x 1.5 https://shop.advanceautoparts.com/p/heli-coil-spark-plug-sav-a-thread-master-set-thread-repair-kit-m14x125-5334-14/9010505-P?c3ch=PLA&c3nid=9010505-P&adtype=pla_with_promotion&product_channel=online&store_code=&&&&&gad_source=1&gclid=Cj0KCQiAyKurBhD5ARIsALamXaEIvlzeT0boeiIgFFGqKG2v0PK5s7Ezg3O49lfJKM3fGt-qM2fqDQcaAusNEALw_wcB&gclsrc=aw.ds Bob that is what I have. Never did this before will give it a try thanks for the info. 2 Share this post Link to post Share on other sites
Retired Wrencher 5,459 #5 Posted December 2, 2023 (edited) You need to break off the internal drive tang at the bottom when done ???? Not sure what you mean buy that. Edited December 2, 2023 by Retired Wrencher Share this post Link to post Share on other sites
WHX?? 48,820 #6 Posted December 2, 2023 There is a small piece of the coil that bisects the coil at the bottom. The insertion tool uses it to install it. It needs to get snapped off after install or the plug wil hit it. It is designed to snap off easy. Ther should be you tubes on how to install it. 2 Share this post Link to post Share on other sites
8ntruck 7,006 #7 Posted December 2, 2023 If you have access to a drill press use it. It will help to keep the tapped hole square. Caution - DO NOT USE THE DRILL PRESS MOTOR WITH THE TAP. Chuck the tap, then turn the spindle by hand, letting the spindle keep the tap vertical. 2 1 Share this post Link to post Share on other sites
RED-Z06 2,221 #8 Posted December 2, 2023 I use these kits for plugs on everything, once you have the reamer and punch you can resupply with just inserts. No tab to break off..you ream the hole, thread in the insert, then put the punch setter in, smack it..this expands the top of the insert to bit into the head. https://www.oreillyauto.com/detail/c/heli-coil/tools---equipment/hand-tools/cutting---drilling-tools/thread-repair/spark-plug-thread-repair-kits/8dc812c8c340/heli-coil-m14-1-25-spark-plug-repair-kit/hel0/533414 1 2 Share this post Link to post Share on other sites
Retired Wrencher 5,459 #10 Posted December 3, 2023 Thanks every one for the info. Did it yesterday. Came out well, 1 2 Share this post Link to post Share on other sites
kpinnc 12,064 #11 Posted December 6, 2023 On 12/2/2023 at 10:41 AM, 8ntruck said: If you have access to a drill press use it. It will help to keep the tapped hole square. Agreed. I have one head that looks like the spark plug is bent... Share this post Link to post Share on other sites
