"Califbill" wrote in message
m...


"Bill Noble" wrote in message
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I think it is more likely because people are ****ed about timing belts.
They have been around long enough that a big group of people have found
out that a $39 tune up is required at a 100,000 miles, but a $600+
timing belt is required at 60,000 miles. And when the belt brakes, it
causes major inconvenience. I do not think anybody makes an
interference fit motor anymore, as they had to warrantee replace a bunch
of motors. People find out a motor requires a $700 fix at 60k miles,
they go to the competitors car.

even more nonsense - any performance motor will be an interference fit
motor as you call it - how could it not be and get decent compression -
econobox motors for little toy cars don't need the performance and can
afford the extra clearance but check ANY car you consider to be high
performance - BMW, Audi, Corvette, Porsche, Lotus, Ferrari, Bentey, you
choose -

those cars you named, probably none have a rubber timing belt, and when
you figure a $800 tune up for the Porshe etc. they are not in the same
league of the cars we are talking about. the econoboxes pocket the
pistons, etc, so if the belt breaks the valves do not hit.

my 911 has a timing chain - actually two of them, but it does have a rubber
cogged belt to drive the power steering pump. However, my 944 (in fact all
944s) have a "rubber" timing belt - of course it's not rubber really, but
it's the black flexible stuff - the 944 uses two of them, one for timing and
water pump, one for balance shafts - I change them at 30K intervals. Audi
TT has "rubber" belt also, only one - the manual says the change interval is
"120,000 miles" - but that's a mistake, they forgot to change from KM to
miles - major lawsuit as virtually every belt broke before the change - in
my case, only 16 of 24 valves destroyed. so, no, in this case you are
wrong - performance cars use timing belts, they use them because they are
lighter, have less inertia, and are quieter than chains. But, with the cost
of labor, and so many folks not knowing which end of a screwdriver is which,
I can see why cheapie cars aiming for reliability might go back to a chain.

That said, the $800 tuneup cost on a 911 is mostly the labor to get at the
plugs - I work pretty fast and it takes four hours to get there, then about
5 minutes to change 12 plugs, then four hours to put everything back -
mostly you have to do things like remove mufflers, sheet metal, etc - it
isn't as annoying as on a cheapie car because the instructions tell you what
to do, and it's all pretty reasonable, just tedious - no like those vegas
where you had to remove a wheel and drill a hole in the fender.....