How to Replace timing belt on BMW Z1 E30 2.5 1993

BMW

Special tools

  • Water pump pulley holding tool – BMW No.11.5.030.
  • Fan wrench – BMW No.11.5.040.

Special precautions

  • Disconnect battery earth lead.
  • DO NOT turn crankshaft or camshaft when timing belt removed.
  • Remove spark plugs to ease turning engine.
  • Turn engine in normal direction of rotation (unless otherwise stated).
  • DO NOT turn engine via camshaft or other sprockets.
  • Observe all tightening torques.

Removal

 

  1. Turn crankshaft to TDC on No.1 cylinder. Ensure timing marks aligned [1] .
  2. E28/E30: Remove distributor cap. Ensure distributor rotor arm aligned with mark on distributor body. E34: Remove distributor cap, rotor arm and backplate.
  3. Hold water pump pulley. Use tool No.11.5.030. Using wrench No.11.5.040, undo fan coupling and remove viscous fan.
  4. Remove water pump pulley.

NOTE: Fan coupling nut has LH thread.

  1. Remove:
    • Auxiliary drive belts.
    • Engine speed (RPM) sensor (if applicable).
    • Crankshaft pulley/damper bolts [2] .
    • Crankshaft pulley/damper [3] .
    • Timing belt upper cover [4] .
    • Timing belt lower cover [5] .
  2. Slacken tensioner bolts. Move tensioner away from belt. Lightly tighten bolts.
  3. Remove timing belt.

Installation

NOTE: DO NOT refit used belt.

  1. Ensure timing marks aligned [6] & [7] . E28/E30: Ensure distributor rotor arm aligned with mark on distributor body.
  2. Fit timing belt in anti-clockwise direction, starting at crankshaft sprocket. Ensure belt is taut between sprockets.
  3. Ensure timing marks aligned [6] & [7] .
  4. Slacken tensioner bolts.
  5. Turn crankshaft two turns clockwise.
  6. Ensure timing marks aligned [6] & [7] . Tighten tensioner bolts to 23 Nm.
  7. Install:
    • Timing belt upper cover [4] .
    • Timing belt lower cover [5] .
  8. Fit crankshaft pulley/damper [3] . Ensure locating pin located correctly.
  9. Tighten crankshaft pulley bolts to 23 Nm [2] .
  10. Install:
    • Water pump pulley.
    • Auxiliary drive belts.
    • Viscous fan and coupling. Tighten nut to 40 Nm. Use tool No.11.5.040.
    • Engine speed (RPM) sensor and distributor (if applicable).

Valve timing procedures

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Bent Valves
Timing Tools?
Misconception
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Bent Valves

What happens when your chain or belt breaks. 

The timing of course becomes way off. Your crankshaft will always spin making the pistons move up and down. However the valves will remain in the position they were in when the belt or chain stopped working. 

Half of the valves will be stuck open and in the way of the pistons. Not all engines, but most. The piston out of valve time will smash right into the open valve and bend the, The only way to fix that is to remove the head and place those valves. 

If you think your valves might have been damaged.

Remove all the spark plugs, valve covers. With both valves in the closed position insert a compression tester hose in place of the spark plug and inject air into the hose and see if the cylinder can hold air. If both valve are closed and air can not be held, chances are you have bent valves.   

 

Timing Tools?

Do you need special tools to time your engine? Not always, on all my post I'll indicate that in each post if you do or not. 

But what are these special tools? Normally you would just line up some marks on the cam and crank gears and simply be done with it. However when these tools are needed they are very very important. 

The last one I did was a 2013 Range Rover 2.0 Turbo with dual cams. There were not timing marks at all. 

There is a small threaded plug on the back of the engine that I removed to insert a special threaded pin that would rest up against the weight of the crankshaft to prevent for DTC of the #1 piston. No further clockwise rotation would be possible. At that point I installed the supplied crankshaft lock by removing the starter. 

Then you line up the back of both camshafts to a notch in each camshafts to each other that a flat tool connects to each cam so they are in line with each other. But first you would make sure both intake and exhaust valves are closed DTC of the cams. 

And the last tool was to lineup the crankshaft position sensor. 

 

Misconception

The most important thing in any major engine work is to rotate the engine by hand at least two complete rotations. And do it easy and slow and with the spark plugs removed. 

Why remove the spark plugs? you may ask. Simple, with the plugs in place you'll be creating compression, making the engine harder to turn by hand and perhaps giving you the misconception of valves hitting the pistons or is it compression.  

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