Quote:

effective engagement ?? no disrespect and don't take it that way but with only a 1/4 inch effective engagement it would be tough to draw down a valve cover with gasket with only a 1/4 inch depth of thread in the head. You need more effective thread depth to pull down the valve cover. Compression of the gasket and the bolt will bottom out.

MLR426



Effective engagement has NOTHING to do with a valve cover gasket.

It has to do with having enough engagement to proper stretch the bolt for it to do it's job and that MINIMUM is the same as the diameter of the bolt in question.

In case you haven't clued in it's NOT the maximum, it is the minimum required. You can have more and still be affective, you cannot have less though.

To further elucidate, that minimum is what is actually threaded into the hole, it does not include the portion that passed thru the gasket or the valve cover, that would be extra.

Ever notice how a standard nut will be as thick as the diameter of it's threaded hole? Now you know why.

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