Chris White

I gotta admire the determination!!
if you want to try it again you might have better luck using an end mill tool bit in the drill.

V2Rocket

so arash, was the time spent worth $325 +s/h to you

determination does produce results.

blade7

The electric drill in his pic was new when he started

V2Rocket

So with some windage ports added, the fancy new-fangled michaelmount rod bearing treatment, and a scraper/windage tray, the 944 lower-end should be apocalypse-proof now!

Reimu

Maybe after a cross drilled crank, dry sump, expensive race oil, and having the shortblock sent to the Vatican for blessing

FRporscheman

At the time, I hated doing all that work and I thought I'd never do it again. But once I figured out the right technique, it wasn't so bad. I'd definitely do it again to the next block. Chris, I'll try the end mill idea. There is a mill and lathe in the shop where I work, and I kept looking over, thinking "I wish I could just mill this bastard!"

Yes, my drill is ancient, but it still works!

I forgot whether I mentioned it, but this block also has the block filler (like Sid). I think I'll use a 3.0L block next time - not just because of the windage ports, but also the raised coolant passage floor and webbed cylinders. But for now, this 2.5 block should be fun. If something happens and this engine doesn't work out well, I'll be out my time but it's been a good learning experience.

H.F.B.

I know, this thread is old, but here is Porsche's explanation, why they did it on the 3.0l engine.
It's from the factory magazine "christophorus" Nr. 215/Nov. 1988:

blade7

Good find, thanks for the translation too.

Mike Lindsey

It's always a hoot when we make up a name for something or a process and it becomes the standard term people call it. Windage Port is one example of this.

Good article, although very short. It backs up what we figured was a common sense modification after noticing Porsche did it on later model year blocks. We have had customers report they can tell a performance gain after it being the only modification done to the engine.

FRporscheman

HFB, very nice find! Thanks for sharing and also for translating, viele Danke!

Mike, what kind of performance gains? Power? I only did this because I thought it would help to reduce oil foaming. Track car, engine is being rebuilt, hoping for many years of (ab)use.

PorscheFanatic202

Dang, wish I saw this thread before I sent the block to Oklahoma.

T&T Racing

Just sent my 2.5L block to Lindsey for windage port modification, piston oil squirters, decking to fix the block surfacing cleaning by a "so called mechanic" and Nikasil cylinder walls because the block blue prints fine but not surfaces not acceptable for race engine

GPA951s

I did my ports myself on two blocks.. EZ, Just a Really coarse Carbide Burr and Lots of WD-40 to keep the bit from loading up... I have thought about Nikasil a VERY good option... But because I have a friend with a machine shop, I purchased all the alu-sil tooling for less than Nikasil- ing one block. Now I can do 15 blocks.. I'm a firm believer in these ports... I'm running an 86 pan on the racecar for 3 years no issues.

V2Rocket

what kind of tool are you putting the Burr into, to get in there and grind?
some kind of right-angle die grinder?

GPA951s

Yes, a right angle Air Die grinder, the trick is the coarse burr, and the WD-40, I did not make HUGE holes in it.. Just like 3/4" Round.. If It took me 20 min to do it it...it was allot... The tool will always be at an angle when grinding you cant hit it straight on. I know Porsche opened up the bottom to follow that casting.. Allot of air can move through a 3/4 hole and you just need it to prevent that slug of air from frothing the oil.. I also left the Middle Boss alone... so 2 holes were good enough because pistons 2 and 3 are on the same plane... Just between 1 and 2 and 3 and 4... This way the Air is getting sucked from the piston going up and pushed from the adjacent piston going down.