I am freshening one of our race motors (we have three of them) and I thought you guys might like to see a few things. You will note on the crankcase picture that the S4 uses four bolt main bearing caps, as does the RS4. The 2.8 A4 engine only uses two bolt main bearing caps. The four bolts give stronger, higher reving capabilities to the engine. If you look at the top of the picture, you will see the crankshaft rod journal bearing surface is offset between opposing cylinders, i.e., cylinders 1 and 4 oppose each other, but they use the same rod journal on the crankshaft. If you look closely, you will see that the rod journal surface is offset, allowing the rods to run at different angles.

The link is to a picture of the lower end of the forged connecting rod showing you how the
rod is cracked versus machined where the upper and lower section of the rod comes
together. This "Crack" gives a stronger surface to bite onto when the rod ends are mated
together and torqued...allowing for less movement.

Don Istook

• http://pictureposter.audiworld.com/1510/mvc-380s.jpg