Installing the timing belt on a BMW E30.


The only tricky part is getting the tbelt over the cam gear.

The problem is that when you turn the crank it creates a tight side and a slack side to the tbelt. The trick is to move the slack to where you need it during the install. Here's the process...

Put the cam gear on to the timing mark. Put the crank's harmonic balancer ~1/4" prior to the timing mark. The purpose of this is to get some tbelt slack on the right side of the cam gear. The crank rotates CW if you are standing in front of your car looking down at the motor. Tensioner should be slack.

The belt should already be around the crank. Using the slack you created, put a maybe 1/4" of the belt on to the right side of the cam gear. Try to get 1/4" of belt width on to as much of the gear as you can.

Now turn the crank a 1/4" or so such that you move the slack to the left side of the cam gear. Don't do this such that the cam wants to move, you are just transferring slack from the right side to the left side of the cam gear.

Now that you have some slack on the left side of the cam gear, you should be able to continue with that 1/4" of belt thickness the rest of the way around the cam gear.

Now turn the crank backwards just a little to move the tbelt slack back to the right side. You can probable slip the rest of the belt on to the right side of the cam.

Turn the crank forwards a little such that the slack moves to the left side of the cam again. Put the belt entirely on.

Turn the crank backwards a little and transfer the slack to the right side. If you're timing marks aren't right, take the belt off and change the starting position of crank.

Tighten the tensioner to remove the slack on the right side.