timing belt or timing chain?

I was reading an earlier thread about when to change out the timing belt.

Please excuse my ignorance...I am not a Hyundai owner yet but am seriously
considering the Tucson or Sante Fe. I thought most new cars nowadays used
timing chains, which I heard can last forever.

Thanks for your response.

yat

 

To this day, most of the domestics still use a timing chain, and rarely does
one ever think about them. A few of the DOHC engines (like the 3.2L and
3.5L in the Dodge Intrepids of the last dozen or so years) used a timing
belt.

Imports much more frequently have used a belt. It allows (supposedly) for
smoother, quieter operation and better fuel economy for the set-up. But of
course, any belt is a maintenance item, and since many of those engines are
"interference" engines, meaning if the belt breaks, you bend or break some
things in the engine (valves, etc.), you best not forget about it.

Something to ponder when you are deciding which vehicle to buy. (All Santa
Fe engines for sure would have timing belts).

Green Valley Giant

 

The Mazda 2.3 DOHC engine has a timing chain, which by itself is good.
It also has something called "Variable Valve Timing", which sounds to
me like a failure waiting to happen.

http://makeashorterlink.com/?Z2C76387C

--

 

I'd say most domestic V-6 and V-8 engines have timing chains, but most
of the domestic I-4's, which by and large are based on foreign design,
use timing belts.

--

 

Not as much of an eminent failure as you might think. Variable Valve Timing
(in different forms) exists in a lot of engines these days. Most
manufacturers either have a form of VVT or are experimenting with it. Some
of the stuff that's being toyed with is quite radical for your basic
internal combustion engine. It's not inconceivable that the camshaft will
become a thing of the past, giving way to the ever-present computer, which
will monitor and adjust valve timing.

 

My 2006 Sonata with the 2.4L engine has a timing chain, if the web site
is correct. I think the new 3.3L V-6 has a chain also, but I'm less
sure on that one.


Matt

 

So do the new Hyundai engines. Time will tell...

Matt

 

And I will add that I am very pleased with the results. My new
Alantra scoots much better than my Accent ever did. The VVT seems to
broaden the torque curve quite a bit.

nothermark

 

My first introduction to a timing belt was when the one on my mid-80s Escort
broke. It was painful!

 

Although Gilmer (that's its real name!) timing belts seem to be a
rather new innovation, they've been used for many decades. That being
said, however, timing chains were generally used by most manufacturers
before the shift to Gilmer timing belts.

Most OHV engine designs used timing chains (most USA manufacturers) or
timing gears (many European manufacturers). Actually, timing gears are
the best, but can be costly to design and manufacture.

In most OHC designs, timing chains were historically used. For
example, the classic Jaguar DOHC inline 3.8L and 4.2L six used timing
chains, as well as most other European cars including the SAAB SOHC and
DOHC inline four. FIAT used Gilmer belts in their 124 series in the
'60s. Mercedes and Porsche used, and still use, timing chains.

Timing chains are more durable than the Gilmer belt. The generally
accepted design spec for replacement of the Gilmer belt is 50,000 to
100,000 miles. Hyundai specifies replacement of the belt at 60,000. On
the other hand, a timing chain - either simlex or duplex - can last
much, much longer. The primary problem with a timing chain design over
time and mileage is chain stretch. This natural wear is compensated by
a timing chain tensioner, either oil pressure or mechanically operated.

One of the primary reasons for the original shift from a timing chain
to the Gilmer belt is one of economics. Although the timing chain is
more durable than the Gilmer belt, it's generally much more expensive
to replace on an OHC engine than a belt. Not only is the timing chain
itself more expensive ($50 to $200), the replacement (labor) can be
very costly. In some OHC designs which use a timing chain, the engine
has to be pulled to effect the repair. Whereas the Gilmer timing belt
is inexpensive ($20 to $50) to purchase, and the replacement cost is
much less than a timing chain. NOTE: Although we Hyundai owners may
complain about this fact, it's nevertheless much less than a timing
chain replacement.

Timing chain replacement in the classic American OHV engine design is
also quite inexpensive, both in terms of parts cost and labor.
Although OHC engine designs are much more efficient, the efficiency
comes at a long-term maintenance cost increase over OHV designs.

 

One of the reasons for the increased cost of using timing chains (beyond
the cost of the parts themselves) is that a timing chain must run in an
oil bath, which in the case of automotive engines, is generally the
sump. That means that it must also have an oil-tight cover over it.

Timing belts run dry and need nothing more than a cheap plastic cover to
keep out dust, dirt and moisture.

 

And then there is my Fort Taurus SHO. Timing belt placement is such
that one the case is opened it is better to replace water pump, front
seal, Crank sensor and a host of other stuff as the labor charge is
monumental. Lucky it's a non-interference engine.

 

Thanks for all the responses. All the information has been helpful. I get
the opinion that the difference in having a timing belt over a timing chain
is that the belt is less expensive...for the part as well as the
installation. Having the belt replaced at 60k miles should be considered
routine long term maintenance.

 

Don wrote: "And then there is my Fort Taurus SHO. Timing belt placement is
such that one the case is opened it is better to replace water pump, front
seal, Crank sensor and a host of other stuff as the labor charge is
monumental. Lucky it's a non-interference engine."......

Actually, that is true with many vehicles, particularly the water pump.
That is often used as the tensioner for the belt, making it something
replaceable when you replace the belt with virtually no additional labor.

But those who said timing belts are cheap need to price out some of them.
The Kia Sedona minivan's does not come cheaper than $110 (that I can find).
That is just the part - with labor, I have one quote for $450, and I have a
hunch it won't get much cheaper. That is not chump change to me.

Green Valley Giant

 

Rev. Tom Wenndt wrote: "The Kia Sedona minivan's does not come cheaper
than $110."

The best price I've found on the Sedona timing belt is $94. Thus, it's
more expensive than your usual timing belt parts cost. I imagine this
is due to the V6 design, and most cost references to belts are those
used in Inline 4 cylinders.

Although $450 is a significant amount of money, it's still cheaper than
some timing chain replacements which require the engine to be pulled
from the vehicle. This is most often the case in some of the European
vehicles.

 

You're correct, Matt. Both the '06 Sonata engines are chain driven.

 

I've never done a Sedona belt, but it's the same engine as the XG, and the
access in the Sedona looks even worse than the XG's.

 

I was quoted $225 Canadian at the Oakville Hyundai dealership?

Chris

 

True, but timing chains seldom require replacement.

 

Except that most timing chains (well, speaking for American engines - I
don't have experience with European designs) will last the life of the
rest of the engine. By the time the timing chain is shot, it is time
for a complete overhaul anway. My Chrysler minivan had 178,000 miles on
it when totaled and the engine was still running fine with all of its
original internal components.

Matt