Tapping Oil Galley for 1/8 NPT plug in BS Delete

Looking for some information on tapping the oil galley for the 1/8 NPT plug in the Balance Shaft Delete procedure. I have used regular taps in the past, but never an internal pipe tap.

I have read several posts where a member of this site drilled the hole almost 2.5", then tapped and ended up with his plug being flush or a little recessed (preferred I would think).

Another member who's plug wasn't flush with the bottom of the block and ended up grind it down flush.

Prior to getting into this, I was wondering if there are any members who know a bit more about doing this? My concerns are that I don't want to drill/tap to deep or drill/tap too far and how I can ensure my plug will be flush with the bottom of the block? I'm also wondering how to use this type of tap in this material. Does it work like a standard tap, where you turn it clockwise several turns and then back a 1/4 turn kinda thing or do you just go forward until you've reached the proper depth. Can you measure the 1/8"NPT tap to determine how deep you need to drill as well as how far the tap should go into the material? Tapping cast iron I have read you do dry without any lubricant, is this right? Also is there not a concern about getting the metal bits from tapping into the "system" and if so what did you do to make sure you got all those bits out?

Thanks.

It does not have to sit flush. In fact the latest kits Aaron sends out are more like a pipe plug which makes it easier to install, hang below the block surface.

The oil galley goes up the block several inches. Longer than your bit will reach. Use a small round magnet to stick up in there to get the metal out.

Oh... so the plug is inside the oil pan mating surface?

vwztips said:

It does not have to sit flush. In fact the latest kits Aaron sends out are more like a pipe plug which makes it easier to install, hang below the block surface.

The oil galley goes up the block several inches. Longer than your bit will reach. Use a small round magnet to stick up in there to get the metal out.

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Yes it has to be as it is the oil feed for the BSM. If the plug stands proud it helps keep the back end of the oil windage tray in place so the oil pan doesn't rest on top of it on reassembly.

LOL I just created another post regarding supporting the windage tray. Leaving the plug proud keeps the windage tray where it should be and not in the way of the oil pan. Okay... got it. I already bought a plug, it's only about 3/8" long though. It's made of brass 1/8 NPT with a hex head. Leaving it protruding doesn't seem like it would have enough "meat" to be in far enough. Ideally it sounds like you would want a pipe thread to go into this oil feed hole left by the BSM, but to also have a threaded stud on the other end of it, drill a hole in the windage tray and use a nut to help support it.

vwztips said:

Yes it has to be as it is the oil feed for the BSM. If the plug stands proud it helps keep the back end of the oil windage tray in place so the oil pan doesn't rest on top of it on reassembly.

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Just tap it and test fit it hand tight so that there are about 2-3 threads remaining. When you finally tighten, you'll have 1-2 threads and there will be enough "meat".

That's what I did (no sealant or tape) and she's been fine for 50,000km

Okay thanks Windex, I'll give it a go. Did you have any trouble getting a drill in there. I read some having to use a right angled drill as there wasn't enough space to get a normal drill in there. I'm hoping that's not true as I don't own one of those, but do have a Craftsman 19.2 volt cordless and a 7.2 volt Makita, but it wouldn't have enough guts to drill metal.

Windex said:

Just tap it and test fit it hand tight so that there are about 2-3 threads remaining. When you finally tighten, you'll have 1-2 threads and there will be enough "meat".

That's what I did (no sealant or tape) and she's been fine for 50,000km

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I never drilled mine. The 1/8" NPT tap I had in my tap and die set worked fine with just a tap handle. Because there were some comments about having a hard time starting the tap, I tried a different tap (different set) and sure enough, it was difficult to start.

If I had a tap which did not want to start in the hole as-is, I would probably ream it out very slightly with a die grinder (chamfer the inner edge) rather than drill - but that's just me. Which ever way you go, take your time and remove a very small amount of material until you can get the tap to grab and start threading.

Here's my funny story from my first BSM delete:

If you accidentally choose the wrong tap size because you have fecal myopia like me (can't see for crap up close wihout cheaters) all is not lost.

I was sure I had the 1/8 npt tap but somehow the threads in the brass plug stripped while trying to start it. I ended up using a metric tap that matched the threads on an old ALH IP distributor head center plug and it screwed in perfectly, and bottomed out with enough head sticking out to keep the windage tray from moving. I also used thread locker just to be sure.

QuickTD, I wish I would have taken your advice... I had a hell of a time getting that 1/8" NPT tap started and once I did, I didn't realize it was going in crooked. So I backed it out and used the non ruler part of a combination square as a guide... kept checking it as I went along, but had to go a little deeper than I wanted. The 1/8 NPT pipe plug is recessed about 3/16"

QuickTD said:

If you tap the hole 3/8-16 and plug it with a short set screw (about 3/8" long), you do not have to drill anything. The tap drill size for 3/8-16 is 5/16. The gallery hole is 8mm, which is too close to call. Run the tap in about 3/8" deep.

I loctite the screw and bottom it in the threads, it will never come out.

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