sump to pump oil galley plug

[cgates30]

I have my engine opened up and am putting plugs into the galley holes. There's a big galley plug where oil from the sump gets drawn up to the oil pump. After some searching I haven't found where many folks actually replace that with a threaded plug. I'm a little concerned about this. I realize that's the low pressure side of the pump, but some marks on the existing plug indicate someone's been hammering at it in the past. I don't know if that's because there was a leak or not. They had covered it with some epoxy, but after the case got cleaned this is what I see:

trash.JPG

I don't know if it was actually leaking, but if tapping/threading is the safe thing to do than I'd rather do it now before things get put back together. It looks like 3/4" NPT would take care of it. The next question is about drilling the hole. When I search 3/4" NPT drill size I see 59/64" for a taper and 15/16" for straight. 15/16" is common enough, but the 59/64" is not. One local shop has one for $55, but I have a 15/16". Am I going to have problems if I use the 15/16" drill?

[Piledriver]

That plug is under vacuum.

It should only get gently popped out from the inside in order to clean the passage.
Someone was sloppy//used the wrong tool popping it back in.

Pressing it back in with a touch of blue locktite or smear of anerobic gasket maker on the OD before pressing in should be sufficient.
It usually gets domed a little when popped out (I use a socket extension)
Tapping it back in flat is sufficient to re-expand it, combined with the smear of sealant on the edge.

You could gently peen around it a little, but that actually risks distorting it more.

I have never tapped/plugged that,(have seen it done) from memory you would have to be very careful not to go too deep or you could restrict the oil pickup passage, may need to shorten the plug to avoid that.

If you are building a turbo motor that might get high case pressure if the ring land failed or such, plugging it or such would probably be recommended.

[cgates30]

That plug is under vacuum.

It should only get gently popped out from the inside in order to clean the passage.
Someone was sloppy//used the wrong tool popping it back in.

Ahhh, that sounds so nice. Was very concerned about restricting flow to the pump. From you post, am I to understand that I should indeed pop it out and then press it back in after applying the locktite? I wish I would have posted this earlier, maybe would have spent time fretting over it being more productive.

[Piledriver]

Clean everything spotless before applying locktite.
Don't smack it too hard driving it out, you don't want to punch a hole in it, its a thin cup.

[cgates30]

I haven't punched it out yet, but before doing so I thought I'd ask what's the best way to put it back in? Just slowly tap it in the center (avoid the edges)?

[cgates30]

Since the case is split and I have free access to the oil pump passages, I'm not seeing a reason to remove the plug (if I should remove it as extra insurance, then let me know). I got some advice from a good source to run a bead of green penetrating locktite around the plug.

[Piledriver]

Socket about the same OD, on a long extension so you can better see it's straight.
Flatten the center back out last to help expand it.

The penetrating locktite will likely work, but use blue, green (the kind for bushing retention) is ~forever.
If you ever want to clean that corner out, you want that removable.