mx5cartalk.com

Hi guys,

My NB8A is sluggish on take off and at low speed. Service was done 6 months ago. Have checked the pulley and have noticed a bit of wobble. Seen somewhere that sometimes this could cause a bit of a timing problem.

I just need to know where to start with a fix for this. Plugs, leads, etc. if it is the pulley, how big a fix is it. Would just changing the woodruff key and keeping all other bits do the trick, or is it best to do complete belt change with water pump?

Your thoughts would be appreciated.

Subsie

There's a wealth of writing about this. Suggest you try reading through some of the miata.net posts here: https://www.google.com.au/search?q=cran ... +miata.net

Just be aware that it can happen to later BP (NA8 and NB) long nose crank engines as well as the earlier 1.6 B6 short nose crank engines. It just requires a mechanic to do a poor job of the pulley replacement during a timing belt change.

Given that you've mentioned the pulley wobble, the symptoms are exactly like the crank nose problem unfortunately, so no amount of changing plugs or leads etc is going to make any difference. There is a chance that the cam(s) were not lined up correctly with the new belt, but again, the pulley wobble suggests that this could not be the case. If you're very lucky the loctite band aid solution could last, but if the crank is too far gone - keyway worn out too far - then it will be time for a new crank, or just replace the engine with another one, which will cost less than replacing the crank.

I know because I had the exact same problem with my NB8B a few years ago, and ended up having to replace the crank.