Originally Posted by
spankaveli
how exactly does the helicoil work? is it just a really tight spring that you can screw the plug into once it's in the hole?
Basically yes.. it's a precision-wound spring made from stainless steel.
They're driven in with an ailgnment jig and a specific tool, then the top coil of wire is snipped, leaving the hardened steel coils acting as threads.
When the coil was installed on my last car, we rotated the crank over to TDC on that particular cylinder, drove in the coil and then drew a vacuum on an air compressor fitting threaded into the newly driven coil. Only a fine silvery dust came out, so that last step was probably overkill.
Since I was replacing the plugs as a set, anyway... I just smeared new anti-sieze compound and installed the new plugs.
Fired up fine, with no loss in power. Continued to run like a champ until I got in over my head with a half-assed wet fogger nitrous setup and ventilated the side of the block.
h: