Drilling NB2 engine block for Accusump ??
 

Has anyone drilled the engine block oil passage pictured for an Accusump feed? Would probobly be fantastic for a turbo feed also?

This pad looks like it was cast for a reason, and has a OD of .800”. Pad diameter is fine, but might be a bit too thin to support 3/8” NPT AN#8 or #10 feed in a high vibration area?

Using a Mocal thermostatic plate to feed my oil cooler on top of a Flyin Miata spacer I have drilled for a pressure sensor.

The trick is the Mocal supplies the cooler before the filter, so no way to splice in a cooler line for filtered oil. Also adding a one way valve to the line doesnt work properly due to bypass properties of the themostatic plate. It seems the filter anti drianback flapper would prevent reversion?
https://cimg6.ibsrv.net/gimg/www.mia...bfc415db7.jpeg
https://cimg3.ibsrv.net/gimg/www.mia...b9f2bc6fd.jpeg
https://cimg5.ibsrv.net/gimg/www.mia...74753a394.jpeg
https://cimg4.ibsrv.net/gimg/www.mia...b37f50c64.jpeg

There is a corresponding boss on the exhaust side that is much more convenient for turbo feed line; on B6s and I think early BPs it came drilled and tapped with a plug in place. There is also a corresponding water port/block drain for water cooled turbo fun. Later BPs have the casting but it’s not drilled.

Don’t see anything wrong with drilling and tapping it, but I’d be worried about getting all the drillings out with the engine assembled and in the car.

Engine is out doing the bottom end due to another issue.

My real worry is how freeken big a 3/8"NPT fitting is, 1/2" is out of the question and how many threads I can get? Looks pretty thin?

I plumbed my Accsump to supply pressure to the oil returning from the oil cooler to the sandwich plate. This goes back through the filter before being fed into the motor. I used an Improved Racing full flow (flapper style) check valve from the oil cooler outlet.

So, the oil goes pump, sandwich plate out, thru oil cooler, check valve, tee (where the Accsump supply is also pumped in), sandwich plate in, filter, motor. That way if there is any dirt in the oil in the Accusump system it goes through the filter before getting to the rest of the system.

Just so happens Improved is just a few miles away and have been buying components from Michael since before he expanded.
The perfect way would be to replace my Mocal plate and run the Improved remote filter where everything would be post filter.
Can also drill & tap into my Flyin Miata spacer 1/2"NPT, which would put it before thermostat. Then add in the backflow preventer to cooler line.

I like the description of your setup, but I'm a "visual learner" so the words get all jumbled up in my brain. Could you scratch out a diagram (pictures would be nice) so I can plagiarize?

I will supply pictures of my completed setup when done.
Plan after talking with Canton tech line is this.
Improved one way valve in oil cooler return line before Mocal block plate thermostat. Tee fitting just as oil enters block Mocal thermostat from cooler. Lightweight braided #10 hose to bulkhead AN fitting. Stainless braided line inside cab to accumulator mounted on floorboard next to tunnel. Manual shutoff with cable actuation just like this.
Thank you to Jesse Prather
https://www.improvedracing.com/high-...eck-valve.html
https://www.improvedracing.com/male-...itting-10.html
https://www.improvedracing.com/light...l-and-oil.html
https://www.improvedracing.com/stain...-nbr-hose.html
https://www.cantonracingproducts.com...NqgVyWmIFgmFkH

I like that he's making a youtube video about everything he knows about accusumps, but has the clamps mounted in the middle, which they specifically say you can't do, because it distorts the bore. Just try to feed the Accusump with filtered oil like Midtenn said, and remember to open the valve and increase air pressure during oil changes, and charge it with increased RPM before shut down. That way you have ~60psi in it for the next start. Only time your motor won't see oil pressure is after oil changes.

You can also use an eletronic valve to open/close it, triggered off an ignition feed, only takes about 1amp. There's a cheaper one without the pressure switch. I'd recommend getting that and triggering it with a PDM, but I don't know if you have one. https://www.summitracing.com/parts/c...RoCumoQAvD_BwE

Here is a rough outline of how I did my setup. Details are going vary setup to setup. The check valve needs to be placed between the cooler and the tee where the accumulator is supplying oil to keep the supply side of oil getting overpressurized.

https://cimg7.ibsrv.net/gimg/www.mia...34f0fc5223.png

Thank you!

That oil feed boss is not tapped on the BP4W/BP6D engines. It's also definitely not simple to add. You need to gun drill the block several inches at an exact angle and hit the oil galley for the rear main.
I can't find the image on this site of a cross section view of the block with the angles required; I hope its not lost to time. It's not trivial even for a good machine shop.