Removing Crankshaft Pulley And Timing Wheel On 1999 Miata

I went through removing the crankshaft pulley and the timing wheel on my Miata to access the timing cover. Below are my notes on this procedure.

Crankshaft Pulley

The easy way to remove the crankshaft pulley is as follows:

  1. With the alternator belt still on the car, remove the four bolts attaching the pulley to the crankshaft.
  2. Remove alternator belt.
  3. Wiggle the pulley off the crank boss.

If you, like me, have taken the alternator belt off the car before loosening the pulley bolts, hold the big 21 mm bolt in place with a ratchet or a wrench while loosening the four small bolts.

In my case, the pulley was rusted solid to the crank boss and would not move. It may have not been touched since the engine was built over 10 years ago.

The first thing I want to state is that removing the 21 mm bolt is, in fact, not necessary to get the crank pulley off. The washer under the big bolt does not interfere with the pulley.

Unfortunately if the pulley is stuck there is no easy way of getting it off. I elected to use a puller to pull the pulley as I certainly did not want to push against the oil pan, and in hindsight anything less than a puller was unlikely to have worked. The trouble with using a puller is that the center of the pulley is pretty much even with the sway bar, therefore there is no way to get the puller on the pulley without major disassembly.

Here is what I ended up doing:

  1. Drain the radiator, unplug fans, disconnect radiator hoses and remove the radiator together with fans out of the car.
  2. Disconnect the sway bar from its mounts to the frame rails (but not end links) on both sides, and let the sway bar dangle.
  3. Install a puller over the crank pulley and pull the crank pulley off the engine.

In the process of pulling the crank pulley with the puller, the pulley was not coming off evenly. One side moved about 2 mm while the opposite side was flush with the engine. I kept pulling and broke a piece of the pulley off. This piece was not important for retaining the alternator belt, as it was on the power steering/air conditioning edge, but after considering that the pulley also dampens engine vibrations

Timing Wheel

As with crankshaft pulley, the timing wheel is supposed to simply slide off the crankshaft boss. On my car, the wheel was rusted to the crankshaft as much as the crank pulley was.

To get the timing wheel off I used a portable torch sold at auto parts stores to heat the wheel around the crank pulley:

Then I stuck a long strewdriver behind the timing wheel and I pried the wheel pushing against the lower timing cover. The timing wheel came off without damage.