Don't know about the Civics, but I recently bought a used 08 Fit. I had
the dealer throw in a set of factory shop manuals.
Looking through the manuals, I was very surprised to find it uses a
I would also like to know the reasoning behind this change. Belts kept
the valve timing tack on till they failed, and eliminated 'internally
lubricated component' from warranty coverage...
there are two main reasons for the trend back to chains:
1. some owners bitch about the cost of timing belt replacement. and
probably with good reason since most dealers take the opportunity to
really hose their customers when they do a belt job.
2. it's part of the general trend towards life limitation. you can keep
a belted engine running for another 100k miles with a belt change.
belted honda engines with 300k+ miles are not uncommon for example. but
you're not going to get that out of a chained engine without a change.
and since no chain change is specified, people will just keep it
running, and by the time they've decided that the thing has worn enough
to sound like a bag of loose gonads, they'll think the motor is dead and
junk the whole thing rather than try to keep it running.
practically speaking, and to be fair, chains have improved a lot.
modern wear rates are relatively low. tensioner strategies have
improved. and they're cheap.
here is the important development that has made them more popular again:
computerized design tools. in the old days, people designed stuff, and
it worked, and that was that. today, designs are so minutely considered
that what used to be wear points or noise points can be addressed and
either reduced or eliminated. for instance, with gears, engineers now
not only design the teeth profiles for maximum strength with minimum
material, that profile is so intricate, it also takes into account the
elastic deformation when loaded in operation! that helps reduce both
noise and wear. to emphasize again, that is a BIG DEAL. applied to
chains and sprockets, that design strategy also helps reduce noise and
wear, thus removing a lot of the issues with chains that belts were used
to avoid. additionally, one of the issues with cams is its tendency to
change its angular velocity as it rotates because of the spring loading
on the cam followers. with computer designed cam profiles, the worst of
that has been reduced, and thus, so has chain loading, and thus also
wear rate and noise. so, while a belt is inherently a better solution
for camshaft drives because it not subject to stretch and doesn't cause
the point loading that a chain does, a lot of the objections to chains
have been reduced, and tied with #2 above, they're an acceptable compromise.
bottom line, we're going to see belts become a thing of the past.
afterall, car companies are run by bean counters, not engineers and
while belts may be technically superior, chains are now an acceptable
mechanical solution, and their financial advantages are significant.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.