Crank Pulley Wobble / Chirp

[DanielJames]

Hi all,

I never really noticed this until the other day when I was driving with my passenger window down.



As you can see, the crank pulley appears almost loose. There is a violent wobble.

Is it common for this to happen? The timing belt was done in April so I'm thinking perhaps it wasn't put back together properly...

Any help appreciated!

Dan

 

[Spacemonkey]

I had that on my MX5 and it was the rubber delaminating that joins the inner and outer of the pulley. It caused the woodruff key in the end of the crank to wear which I fixed with a new key and used chemical metal to fill the gaps, then file smooth. A new pulley was fitted and loctite and correct torque on the bolt used. The pulley is still going strong about 100k miles later. It's a common problem on MX5s and many other cars. Catch it early enough and you'll only have to change the pulley itself.