Cam Belt Replacemnt

I've replaced the timing belts on both my XR4Ti's ('85 and '89). I used the "apply socket&breaker bar->remove coil wire->crank engine" method as suggested in Bob Smith's post. I used a jack stand to support the handle of the breaker bar (car on the ground). To retighten the crank bolt, I used the same socket and breaker bar, ran the bolt down, and then "tapped" the breaker bar a bit with a heavy hammer. This appears to be enough. There is apparently no real force tending to loosen the bolt, so the exact torque may not be too critical. Neil Looney's approach of the air impact tools would be good here as well.

With the damper removed, the basic steps I followed were:

• Loosen the alternator belts and lay them over near the AC compressor.
• Remove the plastic timing cover.
• Set the crankshaft at Top-Dead-Center (TDC).
  If you look at the front of the crank timing belt pulley, you will see a mark, a diamond or a circle. Put white paint on the tooth that corresponds to the mark on the pulley. If you look at the crank seal housing you will see a notch just to the right of center. Turn the crank until the white painted tooth is centered in the notch. This is cranksaft TDC.
• "Detension" the idler and keep it in the detensioned position by retightening the pinch nut.
• Remove the old belt, slip on new belt, retension, replace damper and retighten, replace plastic cover, and alternator belts.

A couple of things to watch for:

Make sure you keep track of the timing marks before removing the belt. Before detensioning the idler (but after loosening the damper bolt), I set the crank at TDC by rolling the car in 5th gear while watching the crank and cam pulleys (assuming a manual transmission; for automatics you can turn the emgine with a socket). When you have the crank in the TDC position, put it in neutral and don't rotate the engine any more.

When setting the tensioner bearing, I like to physically get all the slack in the belt onto the idler side of the belt path before the final setting of the idler. My scheme for doing this is to initially release the idler pinch nut so the idler moves out against the belt. Then I "force" the idler out against the belt a bit more with a large screwdriver. Not a lot of force, but a bit, enough to make you think you've gotten the slack out of the driving side of the belt path. Then, let the idler take it's normal (spring-driven) tension, and tighten the pinch nut.

In short, it's not a difficult job. Changing the belt gives you some peace of mind also, particularly on a recently purchased car when you may not know when it was last done (or done carefully). Go to it!