manant 57 #1 Posted September 21, 2018 I went to replace the spark plug in my k341 and was going to torque to 220 inch lbs but when it got to about 180 inch lbs it was obvious that it was not going to get tighter. The threads are damaged. Is it OK to put in thread inserts? I assume I should remove the head, re-tap the threads and put in a thread insert. Does that alter the plug size? 1 Share this post Link to post Share on other sites
pfrederi 17,028 #2 Posted September 22, 2018 (edited) It does not change plug size. it is a good idea to pull the head so no shavings get inside...I have done two that way. They recommend tread locker on the insert i would do that. Edited September 22, 2018 by pfrederi 4 3 Share this post Link to post Share on other sites
manant 57 #3 Posted September 22, 2018 Thanks Paul. I assume I can get the insert and tapping tool at any auto store. Bye the way, you helped me a great deal with my hydrostatic transmission repair last year. It is going strong. I will always remember your help. 5 Share this post Link to post Share on other sites
pfrederi 17,028 #4 Posted September 22, 2018 Yes to auto parts store... I think I got mine from amazon.. 2 1 Share this post Link to post Share on other sites
squonk 38,565 #5 Posted September 22, 2018 Get the style insert with the serrated teeth. Once inserted you expand the insert with a special tool that with along with loctite will lock the insert to the head, Make sure the insert is in all the way so the plug will be at the correct height. If it's in too far the plug may hit. If it's too shallow, you can burn a piston. 5 Share this post Link to post Share on other sites
WH nut 553 #6 Posted September 23, 2018 For the price of a new used head you may be better off going that way 1 Share this post Link to post Share on other sites
manant 57 #7 Posted September 23, 2018 Thanks everyone. Yesterday I put in a "save-a-thread" thread insert (one with serrations) but have not yet mounted it on the engine. I hope I got it threaded straight. It seemed that the insert went in too easily. I did use the high temp permatex and wanted to let it set for 24 hours. I may get it on today and see what happens. 2 Share this post Link to post Share on other sites