Miata Mailing List: January 1993, Message #2
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   From: (none)
Subject: timing belt
   Date: (none)


I replaced the original timing belt last weekend -- not a very difficult job
as long as you can follow the factory shop manual and figure out how to keep a
pulley from turning whilst the bolts that fix it to its shaft are torqued.
Oh, yes, and the little rubber boots on the ends of the blue NGK ignition
wires put in a while back decided to stay behind in the valve cover after the
wires were pulled out, making it difficult to pull the spark plugs, which have
to come out before the cover comes off.

It was interesting that when I asked the parts guy at the Mazda dealership for
a new timing belt, he sold me two bearing seals (apparently for the two timing
belt idlers, one of which is adjustable to tension the belt) but didn't
suggest getting a new valve cover seal.  The factory manual suggested changing
neither idler seals/bearings nor valve cover seal when changing the belt; I
left the former alone but did replace the cover seal because the old one was a
bit 'dried out.'

At 59,000 miles the old belt looked very good.  There was no cracking,
separation or abrasion; it was just a bit shinier and more brittle than the
new belt.  Peering under the valve cover was interesting.  The aluminum head
wasn't the absolute best alloy casting I've seen, but it's quite complex and
has (to the eye) beautiful machining done on it.  Can anyone speculate on why
the factory manual cautions against turning the engine backwards
(counterclockwise, as one looks from the front)?

On a different subject:  During the fairly recent discussions of Redline gear
lubricants, was there a consensus on which oil to use in the rear end (the
viscous limited slip differential variety)?  I'm running MT-90 in the gearbox,
but seem to remember a different weight (lighter?) being recommended for the
rear end.
_________________________________________________________________

  James Miller -- developing Unix software at (!) IBM -- Austin
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  Internet:  jamesm@voyager.austin.ibm.com   (129.35.131.245)
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