I have a problem with the spark plug stripping out of the head on this engine. After starting it one day I noticed one plug was loose. I retightened it and after the engine was restarted it blew the plug out of the head.
After I installed a head from an RCS140(this engine uses the same head) and finally got a good run out of the engine I found both spark plugs were loose. Since I had tightened them firmly and they were clamped in the RFI boot with a hose clamp they could only come loose by deformation of the threads. It seems logical that sooner or later both of the heads will lose the plugs.
I did not have this trouble with my RCS 140 with about 100 flights. The head that was on the 140 is now on the twin. I wonder if the mass of the RFI boot is causing the trouble.
Putting a helicoil in this head has proved to be a problem. C. Lee does not do this size. The local auto parts store has helicoil kits for 10mm but not the correct thread pitch. I have ordered a tap and helicoils for the correct thread pitch but it will take awhile to get it.
Has anyone else had this problem with this engine? If so what is the solution?


1/29/2004 8:13:16 PM