Weird Timing Belt Marks

[samandw]

I'm helping a friend replace the timing belt + seals on his 1990 240 DL (B230F). After I pulled the timing cover I found the belt to be VERY loose on the side opposite the tensioner. In fact, I could easily twist the belt 120 deg on the slack side

Here's my question:
I pulled the #1 plug and carefully rolled the motor over (by the crank pulley bolt) till it was at TDC (with my finger in the hole to assure that it was compression TDC). When I did this, I found that the line across the old timing belt lined up with what appeared to by the timing mark on the back of the timing belt cover. However, the dot on the cam pulley was 2-teeth advanced from that position. I noted the number of teeth between the distributer pulley and it was correct relative to the cam pulley. I very carefully marked all the positions and dissassembled the timing belt/tensioner etc. My question is this, since the car ran fine when it was parked (with the exception of a massive oil leak from the crank seal), is it even possible that the valve/ignition timing was advanced 2-teeth? If not, why would the marks not line up? Is it possible I'm not seeing the mark that the cam pulley is actually supposed to line up with? Any help greatly appreciated!

TIA

P.S. The timing belt was not original, is it possible that the cam pulley had been replaced with a miss-marked one?

[LaRy]

Actually when istalling the timing belt, all marks will fit, but when you turn the engine around, the marks will not fit at next turn. Anyway, all 3 wheels have marks and it is also marks on the house. You will find the mark for the cam wheel at 12 o'clock, the wheel to the right ( seen from front) mark is 3 o'clock and the wheel at bottom should be something like 11 o'clock. If the engine seems to be running good, the timing belt is most probably correct assembled.
What about the little wheel that should tightning the timing belt. Have you adjusted that? Have you noticed the small rubber plug in the timing belt cover. That wheel should always be readjusted after some miles. Just loosen the 17 mm nut through the hole, turn the enging clock wise something like 120 degrees, close the nut again. Thats all!