Miata Mailing List: May 1993, Message #107
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   From: (none)
Subject: Re: Timing?
   Date: (none)

> From: fischman@nynexst.com (Gary Fischman)
> 
> I'm about to undertake the daunting task of replacing my timing belt.  The 
> dealer wants $400 to do it.  I can buy the belt for about $36. Another $25

The dealer wants $400 because it's a labor intensive job.  I've never gotten one
done myself in less than a LONG weekend.

> for the special tool that holds the flywheel steady while you unscrew it. The
> job seems relatively straightforward.  But I have a question.  Do I need to 
> set the timing after completion of the job?  I've never adjusted the timing
> in the Miata, not because I don't want to, but because it appears that a 
> standard inductive timing light won't work. The factory manual refers to a
> special tool as well as a connection of the timing light to a particular pin
> on a particular connector. 

I've never done the timing belt or the timing on the Miata, but from general
principles I'd say it is not necessary to reset the ignition timing or the valve
timing provided THE ORIENTATION, RELATIVE TO EACH OTHER, OF THE TIMING BELT 
PULLEYS ON THE CAMSHAFTS AND CRANKSHAFT DOES NOT CHANGE.  To be specific, I'd 
mark the position of all three pulleys relative to something (horizontal, 
vertical) before removing the old belt.  If the position of any one of the 
three pulleys changes while the belt is off, the valve timing will have to be 
reset.  However, since the distributor is driven off of the rear of the 
camshaft, the igntion timing should not have to be reset, as it will remain 
relative to the valve timing, unless the distributor is removed.  
> 
> Any tips on replacing the timing belt?  Any "gotchas"??

You'll probably need a puller to remove the harmonic balancer/alternator belt
pulley.  This could be a real B**CH to do because of the close quarters in which
you're operating.  Removing the radiator may be necessary.

> 
> How do I set the timing?  Do I need to buy an "old fashioned" non-inductive
> timing light?
An inductive one should work as well as a non-inductive.  The problem is that
the computer will thwart your efforts by adjusting the timing for you while you are setting it.  There may be a way around this by unhooking the battery, 
setting the ignition timing statically so the computer does not know about it,
but I've never done it on the Miata.
> 
Once again, I have not replaced a Miata timing belt or set the ignition timing,
so this is all based on experience with other OHC engines.  I'd be interested
in hearing from somebody who's already done it. I've got another 30k
miles before mine will need it.

Hope this helps.

Steve