Has anyone tryed to build a VW diesel without a countershft? I was just thinking about this while looking at a 1.6 block I have laying around. You could just ditch the shaft and run a dry sump oil system. Does the countershaft really do anything for harmonics or vibration? Just thoughing this out there, I am sure the Germans know what they are doing.............
I can see how the countershaft on a large single cylinder woks but a 4 cylinder is somewhat balanced...
I doubt it does anything for balancing. It is just a leftover from the gas engine that VW kept to drive the oil pump and vacuum pump. I think it would be way more work than it's worth to get rid of it.
As stated previously, it doesn't do anything for balancing. Actually, inline 4-cylinder engines aren't considered among the smoothest engine designs. In fact, larger ones, such as in the Porsche 944s had balance shafts that were meant to offset the funky vibrations and harmonics that these engines were creating. Porsche had to pay royalties to Mitsubishi for this technology, who held the patent on it at the time. (See, Germans don't think of everything :wink: ) The balance shafts have toothed gears, and timing marks because need to be properly timed in order to do their job.
Even if you got rid of the shaft, you'd have to figure out a way to reroute the belt so that it wraps far enough around each of the pullies to prevent slipping, and do something about vacuum. The Audi and Volvo (VW) 5 and 6-cylinder diesels used a small vacuum pump driven off a pulley on the back of the cam.
Porsche engines are box engines (Horizontaly opposed) are they not? I wonder if this causes more vibration as the crank stress is on the same plane or if this makes it better.
The Porsche 924, 944, and 968 are watercooled inline 4s. The 928 is a watercooled V8. Actually, I believe all of Porsche's engines are now watercooled, whether they're V8s, or flat sixes (boxers).