Lose your timing belt, lose your engine

Watch out! Many Chrysler products use timing belts with non-free running
(interference) engines. When, not if, the belt skips or breaks, your
engine and $8,000 is gone. Even if you get through the warranty period,
the resale takes a big hit because the word has got around.

Chrysler, heed this warning. The public knows gear, shaft, or chain driven
single or double OHC engines are are safe design. Timing belt driven setups
are not.

 

The public could care less, for the most part. Honda continues to be
raved about as the most reliable brand on the planet... and EVERY single
Honda engine is a belt-timed interference engine. Boy, the public sure
is saavy about that...

Go home, nomen.

 

Where are you copying this bull shit from?

 

Why do you think every Chrysler product I have ever owne has had the
3.3 litre V6 engine!

All you have to do is your homework.

 

What a load of misinformed crap....

Must be a Hugo owner...

Honu

 

Probably Toyota or Honda who builds most of this design.

 

Yea, well tell that to all the 2.7 owners who have had either their main
timing chain or one of the 3 chain tensioners fail. Safe design huh ?

There's plenty of Honda's around that have had $1K valve jobs due to
their timing belt failing. I used to own one.

 

That's like saying diesel engines are not good because of what GM did in
the 60's and 70's. Keep in mind that the 2.7 has a sludging issue,
plus, unfortunately, as with the 2.7, many engine designs put the water
pump in the timing belt or timing chain loop - a chain (in this case
literally) is only as strong as its weakest link.

The auto manufacturers are good at taking otherwise inherently
bulletproof concepts when done with a minimum of engineering integrity
and figuring out how to cheapen them to the point that it would be a
miracle if they *didn't* fail - for example, using plastic gears with
timing chains like Ford and GM did.

Bottom line: You can't damn a good method of doing something because of
poor implementation in certain examples - even if the exampes are many.

Timing chains - if done with a minimum of common sense and good
engineering practices - will last the life of the vehicle (gears, even
more-so).

Timing belts are guaranteed to need replacing every 100k or so miles no
matter how well they are designed unless exotic and prohibitively
expensive methods and materials are used (and even then, it may not be
possible).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

It is simply untrue that all timing belt configurations imply an
interference engine. As an example: my '90 Miata and the Mazda Proteges
driven in our family are not. Other examples abound.

As for those which are interference engines: Where is it written that
one can ignore engine maintenance and be entitled to a lifetime of
reliable motoring?

Ken

 

No one made that claim. However there are many more engines out there
that have timing belts and that are interference than not.

The problem I have, Ken, is that it is considered normal to design a
modern car engine that requires a routine maintenance procedure that
costs several hundred dollars to survive much past 100k miles when
feasible alternatives to that design that are maintenance free over the
life of the vehicle are available.

As the cost of the required belt replacement will often exceed the
market value of the vehicle the second time it is needed (i.e., at 200+k
miles), it has to be a huge factor in the number of cars that are junked
that otherwise may have reasonable service life left in them.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

You make a good point, but if you were designing an engine why would you
use a rubber belt and interfering valves? Isn't that stupid?

 

Yes, it is, in my opinion. If you were selling machinery with that
particular built-in flaw, and your competitor didn't have that same flaw,
you'd be at a big disadvantage when selling to anybody who had to maintain
that machinery and was competent to buy it.. Clearly it's stupid IF you
design machinery to withstand forseeable failures.

There are a couple of reasons why they can do it without a severe impact on
sales. Most people who buy cars aren't competent to buy based on that, and
also their competitors do it too. A third reason is that the 2.7 and 3.5
are really strong competitors, maybe partly because of the cars they're in.
Mine have given great gas mileage and plenty of power in big cars.

 

Just FYI - the 2.7 has a timing *chain*.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

The OP did. Perhaps he could have been more precise, but the conclusion
is "Timing belt driven setups are not".

You make a good point, Bill. There have certainly been timing chain
designs that fell short of being reliable (wasn't the 2.6L Mitsubishi
four cylinder used in the earlier Chrysler minivans one of them?). But
you argue convincingly that a rubber timing belt is designed to be prone
to the 100K expense.

I didn't think too deep about this since I do the maintenance and the
expense isn't that much of a burden. In some cases, the even more
failure prone water pump necessitates timing belt replacement as well.

Why do they do this? I suspect it boils down to economics. When the
cycle comes around again, I suspect the victor will be the one with a
"superior" timing chain design.

Ken

 

I'm not seeing that he said that. I re-read his post, and knowing that
there are timing belt engines with interference, and timing belt engine
without interference (thought not very many), there's no place in what
he wrote where I say - wait a minute - that's not true.

Ok - maybe you are saying he should have said "Timing belt engines with
interference engines are not [safe]", but I took that as implied in the
context. But technically (that sentence removed from the context), I
guess you are right.

Not just "prone to", it is required.

Think about if the Ad Council made one of their insipid ads about this.
Assume 150 million vehicles in this country with timing belts (just a
guess - probably more), average annual mileage is 12,000 to 15,000
(implication being a t-belt job required efvery 8 years), average timing
belt job costs $600 (another guess). Also assume 3 hours of lost
production at $20/hr. in dealing with it (time off from work delivering,
picking up, etc.) - another billion in cost.

Then the ad would read something like this:
"The cost to the American consumer for timing belt replacement is 12 and
a quarter billion dollars every year. And that doesn't include the cost
to the environment for replacing the millions of cars every year that
get unnecessarily scrapped due to the cost of the belt job exceeding the
value of the vehicle, or the disposal cost of the used parts, or the
cost to the environment of manufacturing the replacement parts." And
then they'd have a Native American looking into the camera with a tear
running down one side of his face.

It's all due to the huge pressures on the manufacturers for low initial
cost and high integration (light weight, compact) of the components,
which is why simple things on cars that would cost, say, $50 now cost
$800, and people don't even blink when paying it.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Of course that Chrysler 2.7L V6 is a Japanese design.

 

Pardon me?