Drilling the manifold

Is there something I should know before I drill the hole for the egt thermocouple? I think I've read every post here but small things worry me. I know the engine should be running, is idle ok or up the rpm? My thermocouple is a 1/4". Does it really matter or should I wait and get a 1/8"? (Obviously smaller would be less debri but is it a big deal?). Do you let the drill run wide open at point of exit or take it nice and easy, stuff like that. Just don't want to later hear something like "everybody knows you never use a hammer drill with a masonry bit". (Not using a hammer drill or a masonry bit).

Sounds like you're on the right track so far. Yes, leave it running, use the proper sized bit with some oil, both for the drill and tap. Take it slow, and keep the tap straight. Above all, don't get stressed. It ain't hard, you're gonna be just fine. Rick

One trick is to coat the flutes of the tap with grease. The cuttings will tend to stick in the grease. Re-coat the tap with fresh, clean grease, every couple of terns.

You can also attach the magnet to the drill bit. This will magnetize the bit as well as catch shavings, obviously limiting drill speed with this option.

Drilled/tapped several manifolds, and I usually use 1 of 2 methods, first method sprits a little wd40 while drilling slow and tapping slow, then use a shop vac with drinking straw attached to end to suck all metal up

2nd method let it run, spray pb blaster on bit as you drill and tap real slow, everything blows out on its own.

Both work perfect, easy, no stress; do you want it quick and easy? Or a little slower and a little warmer?

Thanks guys, easy peasy. The guy that did it is a machinist and he liked the greased implements method. All that worry and it took literally about 8 minutes.

It’s not a bad job. I was worried too but I was careful and it was much more simple than I thought. A few years later and it’s still working very well.