Originally Posted by davek9

Yeah the "twist" method is not a good way to adjust a T Belt on a 928.

However on an old 16 valve non-interference engine, no real harm if things go south quickly.
On a 32v not so, it gets very expensive in a few seconds

Originally Posted by Steve J.

This is from Porsche service manual 4583.10, "Montage-und Einstellarbeiten"

Originally Posted by Jwrightmcps

"Installation and Adjustment"

Check the Timing belt tension between Cam and Crankshaft. This is where the belt has the least amount of tension. The timing belt should be twisted 90 degrees with your index finger and thumb. It is necessary that while you do this there is a strong force present and it increases while twisting the belt. The engine should be positioned for this test as described in reference number 2.