This seems to be an age old question to which I've found a number of contradicting awnsers to.

When the A6 2.8L (AHA) engine is correctly (mechanically) aligned - crankshaft pulley timing marks aligned and camshaft *larger* holes facing each other (inboard), which cylinder should be at (functionally) top dead center (TDC)?

Now, I've read differing posts on cylinder layout and firing order. I'm going with my Bently manual: "The number 1 cylinder is at the right front of the engine, followed by cylinders 2 and 3. Cylinders 4, 5, and 6 are on the left side of the engine, from front to back." The ignition firing order is 1-4-3-6-2-5

My confusions is that when I have the engine aligned, cylinder 1 is not at TDC as I would expect; cylinder 3 appears to be, however. Is this correct?

On a side note: The engine is running well with no OBD II codes, but the engine make a *lot* of noise. When the engine is rotated by hand, I can hear a mechanical clacking at regular intervals. So this is a function of basic troubleshooting.

Thoughts and opinions are always welcome!

- Martin

 

#3 is the corect answer.