Originally Posted by Droops83

If you are referring to the main electric water pump on the N52/N54 engines, be warned that they are failure-prone. I work at a Porsche/BMW shop and we replace those pumps often. They have an integral control unit that fails, as it is demand-controlled by design. I suppose you could wire it to run all the time, but I'd be worried about the longevity.

There are simpler, more robust electric water pumps out there.

Originally Posted by bebbetufs

I could not find a 90 degree chuck to fit in the bore. You only have 100mm to work with. I would not be comfortable doing anything more than finishing and touch up using a hand operated, high speed, rotary tool in a spot as delicate as this. One slip up and you're done. I ended up ruining my block even on the CNC mill. This is definitely not something to play around with. One 0.03 nick in the cylinder wall and you are probably looking for a new block or at least boring, lapping, new pistons, etc. A slip up here gets expensive very very fast. My credit card bills are proof of this

Originally Posted by blade7

I see what you mean, there may be a small 90 degree air drill out there but it would be a PITA to do. Easier to just use a 2.7 to start with, if only I could find one .

Originally Posted by bebbetufs

Once you factor in the length of the burr even the smallest 90 degree air drills won't fit, unless you hold it at an angle which makes it hard to know what you're doing (I've tried). It can be done, but I would not risk it myself.

A 2.7l short block would be the best way to go. Check out German ebay and wreckers. I just got a block sent up. Shipping cost was €90. (I had to pay €120 in domestic handling fees ) You would be shopping within the EU which should help a lot.