AH Engine – Drilled and Tapped

Drilling the gallery open.
Drilling the gallery open.

So with the garage finally de-chaosed, I could finally get back to working today.

The AH Engine case had previously been degreased, cleaned and pressure washed, and the oil gallery plugs pulled. It was time to finally overcome my fears of messing up and tacking the drilling and tapping, something I’d never done on an engine case, let alone one with such soft magnesium-aluminum alloy.

I carefully drilled out the large gallery holes since there is some material that needs to be removed, and the fitting (or plug) is larger than what was originally there. Basically doing what I’d seen done by EZGZ in one of his vids, I carefully and manually bored the drill bit into the holes, slowly removing the excess material via a wrench attached to the bit.

I did the same for the older holes as needed to prep for the tapping.

Tapping holes!
Tapping holes!

I then slowly tapped each hole to the appropriate size.

Tapping holes!
Tapping holes!

I realized my tap set couldn’t handle the larger NPT taps so I had to slowly do it with a vise grip. I made one pass, slowly backed them out, cleaned out debris, and then did another pass.

I repeated this with different sized NPT taps throughout the case.

Tapped (rear)!
Tapped (rear)!

 

Tapped (top)!
Tapped (top)!

It is an extremely mess job. There was fine metal debris everywhere.

On the whole, I think I did an excellent job for an amateur in a garage.

That said, I did learn somethings and will likely go a different route tomorrow.

The “EMPI” threaded gallery plugs you can buy at the usual resellers suck! And I mean suck major balls. The metal is so soft that I stripped the allen socket manually just trying to put 2 in and then take them out!  I then had to basically drill the new plug out, smash the top part that did not go in, then use a vise clamp to grab it to have enough leverage to screw them out. Just awful!

Yes. They need to be of a material that matches the thermal properties of the block. But they are just too soft. Hell… I can’t imagine trying to do plug the rest of the case now without getting angry as hell with these.

So. What to do?

I think I’m going to head to JEGS tomorrow, possibly even taking the 1 case half, and do this engine with AN fittings and plugs. The store has practically an entire wall devoted to every type, size, and color. I need a 90° angle fitting for the return oil anyway so I was going to have to go there anyway.

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