Tip for valve cover Heli-Coils

In the past, I had to use Heli-Coils since a previous mechanic had gotten overzealous and overtightened the valve cover bolts, which stripped them out.

When I installed a couple of Heli-Coils last time, I ended up ruining a couple of the coils since they did not go into the hole easily.

This time, however, I noticed something–the tap was not cutting the threads deep enough.  These holes are shallow, and the taper of the tap was not allowing it to go in deep enough to cut good threads.

Grinder to the rescue.  I ground the bottom of the tap flat, turning it into a bottoming tap.

Success! The coil I installed last night went in, as they say, “like buttah.”  And I have a valve cover properly installed now.

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