Read this page - http://www.miata.net/garage/crankshaft.html - for all the
info.
It is NOT necessary to remove the crank timing belt sprocket to change
timing belts. Unless your front crank seal needs to be replaced, leave it
alone. My '91 Escort GT has the Mazda BP1.8 and is of very similar design
(and as I've read, I may have the "dreaded" short-nosed crank). My engine
has 212,500 original miles so I'm on my fourth timing belt and I've never
needed to disturb the crank timing belt sprocket.
I suggest changing the timing belt yourself, save the $$$ and learn
something about your engine. I've become quite adept at changing my belt
and water pump. It's quite easy once you've got a routine down and I WISH
my transverse installation were nearly as accessible as the Miata's
longitudinal one!
Proper installation of the key is always an issue but it's less critical
with the longer-nosed crank.
A factory manual is HIGHLY recommended over Haynes, Chilton, etc. Look on
eBay, I got mine for about $40.
Will Kalman
'91 Escort GT
CSCC #232 STS
>
> Provided the car is a "latter-half" of '92 model (I forget where the VIN
> #'s start), the keyway is not an issue. On 90-early 92 Miatas, there is
> sometimes crank failure related to the nose splitting which is related to
> improper timing belt change procedure.
>
> If the belt hasn't been changed, it's a pretty easy process for anyone
with
> basic mechanical skills, following your Haynes or Mazda factory service
> manual as well as all of the informative pages within Miata.net. There's
a
> ton of room in there---Miata engines are incredibly easy to work on! IOW,
> don't pay the dealer $400+ for something you can do yourself.
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