12/29/06 – Finishing the oil pan
I used a roll form 1" NPT tap. This tap actually requires a larger hole because it actually forms the material vs. cutting it. Since my holes were slightly large as it were, this worked out well. I purchased two 1" NPT socket head pipe plugs in cast 356-f aluminum.1 (the same material the pan is made from2). I then coated the plugs in high temp, oil resistant epoxy and threaded them into the holes. I tightened them with a 1/2" breaker bar. Since both items are of the same material, both will exhibit similar heat expansion.
The pan with the plugs installed:
The pan on the engine:
The plugs have been curing for about 14 months. They should be ready to go.
(1) Mcmaster Carr item 44705K337