Drilling for oil... in an NB case?
 

(To the tune of The Beverly Hillbillies)
Getting ready to take this engine block to the machinist, and an idea occurred to me.

On the 1.6 and (allegedly) early 1.8 blocks, there's a convenient threaded port on the hot side of the block back near the bellhousing where oil is taken to supply the turbo. The later cases obviously don't have this hole, as they were never used in a factory turbo application:

https://www.miataturbo.net/attachmen...1&d=1415546112


Now the question is, would it be practical to add this hole to a later block?

When I originally thought of this, I didn't have an engine block right in front of me, so I figured maybe there was an oil galley running right behind that position just waiting to be tapped into. Now that I've looked closely at the back of the case, I'm thinking this may not be so. If my assumptions are correct (judging by the location of plugs and lumps) this is basically what Superman would see if he looked at the back of the case with his X-ray vision:

https://www.miataturbo.net/attachmen...1&d=1415546112

Looks like in order to reach oil, you'd need to drill roughly 5 inches into the case. I'm not sure I'd trust a machine shop to make this cut, given that if they go slightly off-axis, the case is pretty much junk.

I was really hoping to avoid having to run a hose all the way around from the pressure sensor port. That rubs me wrong in much the same way as the stock Greddy drain configuration...

Thoughts?

I wouldn't be comfortable with someone drilling that far into the block unless they had some seriously precise equipment. Trying not to ask the obvious, but what's to keep you from finding an early 1.8 block with the oil port already there? My '95 block had the provision whereas a friend's '96 did not.

Laziness and cost/benefit ratio. Apart from a little external surface rust, this block is in excellent shape, and I really don't want to bother with finding another just because of the oil feed hole. I won't kill me to run a line across, I just wanted to avoid it if possible.

Maybe someone has a nice rod-sized hole in a BP-4W block and wouldn't mind donating it to science?

Otherwise, running the oil feed across the motor is certainly more sane than the return.

just get a hose. lol

5" hole is not bad at all. Start with a good short center drill, than a short drill for rigidity. Step up to a longer drill and the "pilot" hole will guide it and keep it straight. This is all on a radial drill or mill of course. With the transmission mounting face and head surface or oil pan surface, you should be able to get some pretty precise measurements for hole location to the machinist.

I would do it in a heartbeat.
I drilled and tapped my '00 block for water. I didn't dare to do it for oil because I was afraid to get shavings into the oil system. I would work just fine though.
Did it with hand tools btw. Lightly pressurised the system while I was drilling with a tiny drill bit. When it broke through, water squirted out. Upped the pressure a bit and drilled with a bigger bit. Worked like a charm.

http://img17.imageshack.us/img17/6192/drillforwater.jpg

http://img188.imageshack.us/img188/5...lantsupply.jpg

Frank, did you do both the water and oil holes?

I'd been planning to draw water from the front of the engine (where it's presumably a bit cooler) but I suppose the lines will be neater taking it from the side. How deep did you have to drill for the water line?

Interesting, but I'd be at least a little wary about drilling all the way in there and getting a shaving into the route to the rear main. I'm a little biased though, I've had customers before with all sorts of bearing problems from incompetently drilled feed and return lines. One had a return line that he just drilled strait into the side of the oil pan without any precautions, needless to say his debris filter was covered in shit.

I didn't drill for oil as I did it on a completely assembled engine and this would have caused shavings to get into the system. The coolant system can be flushed out and wouldn't cause any damage should something be left inside, but the oil system is a different matter. However, if I had the engine completely apart like you have, I'd have it drilled for oil as well because I'm using a MSM turbo with its hard lines. In my case, I'm gonna cut the hard oil line at the 90° angle, connect a rubber hose to it and T off the oil pressure sender.
I did this over a year ago, so can't really remember exactlyhow deep it was, but I'd say almost an inch. I remember it was deeper than I expected.

Old bump but, does anyone recall how deep the oil galley is?