I wish we could make it easier than it is to time the cams on these cars and set up the mechanical tensioner but it seems to be there is a mental block when it comes to this style mechanical tensioner. You can't use the don't force it just use a bigger hammer mythology.
Granted it isn't what is should be and was originally used on a later Alfa engine with a little different set up but the design causes that issue of possibly breaking outer spring when trying to force body to move by using lifting lug only (the reason for using needle nose pliers in the two holes in the pulley pivot point to start the over center movement).
Alfa 164 TSB 01.93.03
Step 13. INSTALL A NEW TIMING BELT. PAY CLOSE ATTENTION TO THE TIMING REFERENCE MARKS MADE EARLIER. USE SPECIAL TOOL (PART NUMBER 608-97517) TO RETRACT THE TENSIONER PULLEY*
AND SLIP THE BELT OVER THE TENSIONER PULLEY. DOUBLE CHECK THAT YOU DID NOT DISTURB THE TOP DEAD CENTER POSITION OF THE CRANK SHAFT AND THAT YOU ENGAGED THE APPROPRIATE TEETH OF THE CAM DRIVE PULLEYS. USE GREAT CARE SO AS TO MAINTAIN PROPER CAM TIMING. ON MILANO AND GTV 6 MODELS YOU MUST PROPERLY INDEX THE AUXILIARY DRIVE SO AS TO MAINTAIN THE PROPER IGNITION TIMING.
NOTE: FOR ADJUSTMENT / SET-UP PROCEDURES - SEE TECHNICAL BULLETIN 01.93.04
* special tool = needlenose pliers
Alfa 164 TSB 01.93.04
1. With engine cold and positioned at top dead center, loosen both tensioner retaining nuts. Use a 3/8 square drive inserted into the lift square (see Figure "A" attached) of the tensioner and rotate the assembly counter-clockwise (into the drive belt) until a resistance is felt.
CAUTION: Do not use excessive force! Torque applied to the lift square must be at least 11 foot pounds but no greater than 18 foot poinds. Too much force may damage the clutching mechanism.
INSERT STEP 13 FROM FIRST BULLETIN: USE SPECIAL TOOL THE NEEDLENOSE PLIERS (PART NUMBER 608-97517) TO RETRACT THE TENSIONER PULLEY
AS YOU START TO LIFT TENSIONER BODY WITH LIFTING LUG SO BODY MOVES EASILY OVER CENTER TO PREVENT SNAPPING OUTER SPRING.