Drilling, tapping and plugging the oil galleries

[Dangermouse]

Well I think I’ve read every thread on every forum and I’m still not 100%; I’m surprised there hasn’t been a better step-by-step written somewhere for unplugging oil galleries, tapping and plugging them. The sticky on here was lacking a little in the details which newbs like me need

Specifically -
• Does each and every gallery plug really need to be done, or just some of them (which ones)?
• What’s the deal with the plug which leads to #4 bearing; should I pull it or leave it alone? Concerns raised due to worrying statements like this…

Don't pull out the tiny one on the pulley end of the case. Apparently, the extra length serves as a restriction to oil flow to #4 main. Supposedly if you replace this plug with a shorter pipe plug, you will blow oil out the pulley as the bearing wears. I have no firsthand with this, but I cite this as a reference;

http://www.thesamba.com/vw/forum/viewtopic.php?t=277850

http://www.thesamba.com/vw/forum/viewtopic.php?t=280293

• Thread sealant – Loctite 518 anaerobic flange sealer seems to be popular as does Loctite blue threadlocker. Preferences?

Tooling -
I’m not in the US and the NPT standard is not common where I live (but the fittings are so easiest to stick with that) which means I can’t wander down to the hardware store. I can buy the taps cheapest online from somewhere like http://www.victornet.com/departments/Taps/100.html (McMaster-Carr won’t ship internationally unfortunately). This means I need to be particularly careful with choosing the correct ones.

So far I’ve picked out:

• 1/8"-27 NPT National Pipe Taper HSS Pipe Tap
• 1/4"-18 NPT National Pipe Taper HSS Pipe Tap
• 3/8"-18 NPT National Pipe Taper HSS Pipe Tap

• 21/64" HSS Drill Bit
• 7/16" HSS Drill Bit
• 37/64" HSS 1/2" Shank Drill Bit

Are taper taps appropriate for doing this job? They seem to be more commonly available then plug taps which I can understand might be better. Reamers to create the taper prior to tapping – necessary or not? Dire warnings exist with regard to cracking the case if the drilled hole is not reamed appropriately prior to tapping.

Questions, questions, questions; I'm sure I'll have more soon... Hints and tips would be much appreciated.

[Devastator]

• 1/8"-27 NPT National Pipe Taper HSS Pipe Tap
• 1/4"-18 NPT National Pipe Taper HSS Pipe Tap
• 3/8"-18 NPT National Pipe Taper HSS Pipe Tap

• 21/64" HSS Drill Bit
• 7/16" HSS Drill Bit
• 37/64" HSS 1/2" Shank Drill Bit

You should replace the 21/64" drill with a letter R drill which is .339 instead of .328.
The other 2 drills are correct.

Are taper taps appropriate for doing this job? They seem to be more commonly available then plug taps which I can understand might be better.

The simple answer here is yes, the taper taps are what you are looking for. A plug tap is a description of the point style available. There are plug, gun, and bottoming taps for most straight threads, but tapered threads, and taps, are different. Unless the hole you are tapping is fairly deep, go with the shorter length tap, otherwise you'll bottom out before getting enough thread to seal properly.

Reamers to create the taper prior to tapping – necessary or not?

Not completely necessary, but recommended. Tapered taps, especially the bigger ones like 3/8-18, require a LOT of torque to cut. This is where the possibility of cracking the metal around the hole, (the boss), can occur. I recommend you try tapping a hole in a scrap piece of aluminum, or an old engine case to get a "feel" for it, before you tap something as precious as an engine block. So, to answer your question, yes, use a tapered reamer to substantially reduce the possibility of cracking the boss that you are tapping.

Hints and tips would be much appreciated.

There are staggered tooth taps available for these thread sizes. Staggered tooth taps work very well in aluminum alloys and require less torque to cut a thread. Use a light cutting oil or even kerosene for aluminum.

[trmunion]

Devastator is nutz on. I just did my AE case, was a straight forward job, Just take your time and be sure to start the tap square to the surface your tapping, I used riffle cleaning kit to clean out the galleries. A lot of them had been plugged up from my case sitting in garage for years( insects ?? mud dobbers?) I also used HP air to blow everything clean. Good luck

[Dangermouse]

Just the sort of practical help I'm after; thanks for that.

Have changed order to interrupted pipe taps, like this...



hope this is good for AS41 magesium alloy also.

Have also added a 3/8" NPT pipe reamer for the larger holes anyway


Changed that drill size too.

Anybody got any thoughts on the #4 bearing issue? I'm inclined to steer clear of it...

[trmunion]

I did the #4 but wasn't aware of the long plug. but I found with riffle cleaning kit I could have just use the other end and not had to use the #4 hole.

[Devastator]

Have changed order to interrupted pipe taps, like this...

Image

hope this is good for AS41 magesium alloy also.

That is the tap I was referring to and, yes, it will work great in aluminum or magnesium and their alloys.
The reamer is an excellent choice too.
Maybe you could offer to sell them as a "kit" in the classified section of this forum, after you're done with them.

[fusername]

Have changed order to interrupted pipe taps, like this...

Image

hope this is good for AS41 magesium alloy also.

Maybe you could offer to sell them as a "kit" in the classified section of this forum, after you're done with them.

a good plan, saves someone some time and money, and are you really gonna need them again? I kept mine cause I have built 3 more engines since, but most folks don't play in the mud like i do. I have never tried the kerosene as a cutting fluid trick, nor the intterupted tap, I always used tap magick, worked good for me. or you can use rector seal #5, which is also a good sealent for the threads, availble at home depot in the states, not sure how avail it is wherever you are.

as for #4, I would just leave it

[Devastator]

I always used tap magick, worked good for me. or you can use rector seal #5

Tap magik is a great lubricant, once you get past the smell. You'll find that using the interrupted flute tap will reduce cutting pressure required to tap the hole, and also the necessity for a tapping compound. If you want to go cheap, simply used diesel or WD-40, the former being preferred. Only enough to cover the cutting edges is needed. I should reinforce that the taps and cutting fluids I'm recommending are only for aluminum, magnesium, and their alloys. Using the interrupted flute tap in steel will not be very effective, and probably break. Also, for steel, a heavier lubricant is suggested instead of those I recommended in this thread.
Rector seal is a great sealing compound for sure. Xpando is another fantastic pipe sealing compound that I highly recommend. I've subjected Xpando to 425 degrees, (f), and 250 PSI, and it did not fail. As far as my engine block goes, I just used teflon tape without issues.

[bugninva]

. Xpando is another fantastic pipe sealing compound that I highly recommend. I've subjected Xpando to 425 degrees, (f), and 250 PSI, and it did not fail. n .

Xpando is wonderful.... I bought a case of it years ago when I was a pipefitter/boilermaker.... that is a couple lifetime supply... but good stuff... that said, I use blue loctite on the plugs when I plug the gallies....

[Dangermouse]

All great info; thanks peeps.

I think I'm ready to go for it ; I'll post some pics of my progress.

As for selling on the taps and acoutrements after I'm finished, it's not a bad idea but I doubt I'd be able to bring myself to do it (though I probably could very easily). I've never seen tools as anything other than an investment and I'm sure there'll be a next time...

[blue77bay]

when i did mine a year ago i did the 4 bearing plug as well ,there was a long thread somewhere regarding it ,BUT, after looking at the 4 bearing it has a built in restrictor at the bearing shell so i did it ,i think it should be done simply so you can get in to clean in there and it cant fail

[Clatter]

It's important to go gently as you tap.
Turn a whole (or half) turn, back it out, blow all the chips/swarf away of both hole and tap, then take another turn.
Repeart as needed until depth is reached.
A lot of the time breakage issues are a result of the tap getting clogged and binding.
You also want to check the fit of your threaded plug as you go, so you can 'walk up' to your preferred depth.

[Dangermouse]

Good advice duly noted, thank you.

One of the first obstacles I've run into is that I don't think the fitting I've been sent by a supplier for the oil return into the case is going to work. From what I've seen, the most common way to return from the oil filter is to tap back into the case at the main oil gallery using a brass 3/8" elbow fitting like this -



which still requires some clearancing of the adjacent boss to allow it to wind down





The fitting I've received looks like this -



As you can see, it seems to be considerably bulkier than the ones pictured; it would take a lot of clearancing to make space enough for this thing to turn around (possibly right through to the passage inside that boss). I just can't see it working...

I expect I'll be sending this fitting back but I just want to know I'm not missing something here.

[Hedrock]

Here is how I did mine. A 3/8" #8 straight fitting... then a #8 90.

[Devastator]

Here is how I did mine. A 3/8" #8 straight fitting... then a #8 90.

Mine is similar to this, but I used a close nipple and a female-female elbow.