Guest Posted December 23, 2014 Report Share Posted December 23, 2014 All the threads were clean, absolutely clean ,no corrosion. There was a slight sign of rust (iron oxide) in the hex drive of the plug. If there was corrosion I doubt it would have come out at all. These cylinder assemblies have many steel /aluminum contact surfaces with no corrosion issues. This plug is listed in the parts guide as 1/8 x27 x pipe thread. There are different tapers for pipe threads but pipe thread tends to wedge itself into the female thread for sealing and locking.. Normally Lycoming installed a helicoil in pipe threads in cylinder heads. Clarence Quote Link to comment Share on other sites More sharing options...
jetdriven Posted December 23, 2014 Report Share Posted December 23, 2014 Except in the IO-360 fuel injector nozzle holes. Then if the injector gets loose it vibrates in the hole and strips the hole. It's 1/4" NPT and Lycoming specifies 50 inch pounds btw. Come to think of I i have never seen an NPT helicoil in a Lycoming engine Quote Link to comment Share on other sites More sharing options...
Guest Posted December 24, 2014 Report Share Posted December 24, 2014 Current IPC shows the following: STD1872- 1/8"-27 insert helicoil tapered 1102-plug 1/8-27 NPT, Allen Both are used in the injector hole as well as the MAP/ primer jet hole. Clarence Quote Link to comment Share on other sites More sharing options...
jetdriven Posted December 25, 2014 Report Share Posted December 25, 2014 I wish they heli-coiled the injector holes in my cylinder heads. They were simply tapped and the threads were very poor quality. #1 and #3 were also tapped to the wrong depth, torquing the injector to 50 INLB they were upside down. Undertorquing them slightly they woud kinda line up, but they fretted in the holes and now those two are stripped. Quote Link to comment Share on other sites More sharing options...
Guest Posted December 26, 2014 Report Share Posted December 26, 2014 Im sure you could buy the helicoil kit for less that the cost of replacing the 2 cylinders. $110 on Amazon. Clarence Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted December 26, 2014 Report Share Posted December 26, 2014 My current IO-360 is the fourth one I've owned. None have had helicoils in the injector holes. Mechanics have been fixing stripped cylinder holes with helicoils for ever. I would imagine in today's environment some may be hesitant to do any repairs unless they are explicitly authorized. By putting the helicoils on the parts list, it authorizes them to be added. I wouldn't add them unless mine were stripped and I couldn't fix them with a pipe tap. Quote Link to comment Share on other sites More sharing options...
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