I'm replacing the head gasket in my 1996 Jeep Cherokee Sport, straight six with fuel injection. I'm using a Hayes manual as a guide. Following the manual I aligned the timing mark to 0 degrees in order to set the number one piston at TDC.

The rotor button however does not align with the number one plug wire, its about half way between the number one and the number five plug wires on the distributor cap. The manual also says that the distributor in the straight six is not adjustable, meaning I suppose that the timing mark is irrevalant.

So why does the block even have the timing gauge ? How do you set the timing ? If the rotor button points to the number one plug wire is that truly TDC ?

 

It is not adjustable. PCM takes care of the timing based on the CPS signal for the most part.

 

Mark the position of the #1 plug wire on the distributor, rotate the engine clockwise at the vibration damper until the distributor rotor points directly at the #1 plug wire location on the distributor, the "0" mark should be aligned with the notch on the damper. This is TDC Compression stroke. What you are seeing may be that the #1 piston is at TDC of the Exhaust stroke.