If you are unfamiliar with this job, please refer to the Milano Workshop Manual (available as a CD-ROM, IAP part number 10023), pp. 00-26 ~ 00-28 and 01-74 ~ 75 and/or the GTV6 2.5 Engine Maintenance Manual (CD-ROM, IAP part number 92200), pp. 21 ~ 22, before starting.
Always rotate the engine in a clockwise direction, as viewed from the front of the car — the bottom of the crankshaft should always rotate toward the passenger’s side. Reverse rotation will cause the timing belt to slip.
Rotate the crankshaft until the engine is at top dead center, on the compression stroke of the #1 cylinder.
The engine is at top dead center when the “P” mark on the crankshaft front pulley (see Fig. 1) is lined up with the pointer on the front of the engine (see Fig. 2).
Figure 1. Crankshaft Top Dead Center
Figure 2. Crankshaft pulley (1) and Pointer (2)
The engine is on the #1 cylinder compression stroke when the distributor rotor is pointed toward the #1 spark plug wire terminal (see Fig. 3). The center of the rotor ® should be aligned with a notch cut in the top surface of the distributor body. If the rotor is pointed toward the #5 spark plug wire terminal, rotate the crankshaft 360 ° ( clockwise), until the “P” mark on the pulley lines up with the pointer again, at which time the rotor should be pointing toward the #1 plug wire terminal.
Figure 3. Distributor @ TDC, #1
With the crankshaft at top dead center, and the #1 cylinder on its compression stroke, put a mark on each of the camshaft pulleys at 12 o’clock, and on the camshaft/oil pump drive pulley at 9 o’clock (a Sharpie works well for this). Put a corresponding mark on the timing belt at the same locations with a white china marker or grease pencil (see figure 4).
Figure 4. Timing belt and pulley marks
Loosen the timing belt tensioner, and remove the timing belt. Count the number of teeth between the marks on the timing belt. Put marks on the replacement belt to correspond to the marks made on the belt being replaced. Fit the replacement belt on the pulleys in the following order:
- Crankshaft pulley
- Driver’s side camshaft pulley
- Passenger’s side camshaft pulley
- Distributor/oil pump drive pulley
Re-tension the timing belt (if you have the hydraulic belt tensioner, refer to the workshop manual; if you have the mechanical belt tensioner, refer to IAP Technical Bulletin 661039, “Timing Belt Tensioner”).
Rotate the crankshaft 720 ° , and check that the marks on the camshaft pulleys are at 12 o’clock when the crankshaft “P” mark is aligned with the pointer, and that the distributor rotor is pointing to the notch in the distributor body that indicates the #1 spark plug wire terminal.
If all the marks still line up, the timing belt was installed correctly and did not slip; if the marks do not line up, the belt slipped and must be re-installed on the pulleys.
The previous instructions apply to engines that were running satisfactorily at the time of the belt replacement. If the engine was not running prior to the belt replacement, please see Figs. 5 and 6 for the marks on the camshafts that should be lined up with marks on the cam bearing caps when the crankshaft is at TDC on the compression stroke of the #1 cylinder. This will require removing the cam box covers.
Figure 5. Passenger's side camshaft timing marks
Figure 6. Driver's side camshaft timing marks