Timing belt Vs. Timing chain?

cojomo2 · 10-04-2009 2:14pm #1

hey,

i understand timing belts have to be changed evry 60k miles or there abouts...

what about timing chains? I understand these usually never have to be changed, but is it true they need to be 'tightened' every 60k miles or so or is this just rubbish?

mike65 · 10-04-2009 2:16pm

Depends on the model, some will need the chain tensioner replacing at some point for example.

cojomo2 · 10-04-2009 2:19pm

ok..well basically what im asking is:

if something goes wrong with timing belt i.e it snaps as you didnt replace it in time, i understand very serious damage to the engine can result...

can the same happen with the timing chain? or is it more likey i will jut hear a dodgy rattly if it gets slack?

it a 06 pajero by the way. cheers

mike65 · 10-04-2009 2:28pm

Engine design varies, some are "non-interference" so if the belt snaps the expensive bits do not meet and greet at great expense. Chains do tend to give early warning such as rattling, a chain can be tested by hand, also a stretched chain can cause the engine timing to go off.

Johnboy Mac · 10-04-2009 4:31pm

Timing Belts: Replacement required anywhere between 30-100k mls, depends on the actual vehicle. Also very adviseable that the tensioner, idler pulliers and water pumps are changed also, this again depends on the vehicle.

Timing chain: Manufacturers generally don't specify when a t/chain should be repalced as they have generally speaking tend to have a longer life (steel v rubber). It's not uncommon for chains, guides and tensioner to be required at 100k mls, again this variers from vehicle to vehicle and standard of servicing the engine has received.

leitrim lad · 10-04-2009 4:42pm

the chain is the way forward, and i can see in the near future gears being the new chain, as belts are to dodgy nowadays

the chain should only have to be changed once in the lifetime of the engine, so between 100k and 150k miles,

thats when it would normally start to get slack, and there is a slim chance of it breaking compared to a belt, more chance of it coming off when slack , and even at that its a very small chance

that also depends on how well the engine is maintained, ie service regular

mick.fr · 10-04-2009 4:49pm

Not trying to be smart here, but it has been a while many engines do not use timing belts anymore but timing chains. Even though we still call them "Belts" they are actually chains..
This is the case with quiet a lot of manufacturers at least.

gofaster_s13 · 10-04-2009 4:53pm

mick.fr wrote: »

Not trying to be smart here, but it has been a while many engines do not use timing belts anymore but timing chains. Even though we still call them "Belts" they are actually chains..
This is the case with quiet a lot of manufacturers at least.

80% of cars still use belts

mick.fr · 10-04-2009 4:55pm

gofaster_s13 wrote: »

80% of cars still use belts

Says who/where? There is a very good reason for not using a belt anymore for the timing.

garyegt · 10-04-2009 4:56pm

not sure about the mitsi engines but i have a timing chain in my car, it has 145000 miles and on startup theres slight chain rattle etc but its still ok.

the thing with chains is tho is that the engine does need lots of fresh oil n filter in it to keep em going, for example i change mine every 5k.

so all i can say is keep your engine well lubed up at all times and if there is ever signs of stretched chain like lumpy running, suspect a stretched chain and get it fixed asap! but seeing yours is 06, as long as its not ragged with no oil your fine:)

biko · 10-04-2009 4:56pm

The chain in a Saab I had gave up after 150K. You could tell by the noise (of course) and also by the tiny metal fragments in the engine oil. Would have been >1000 to fix.

peasant · 10-04-2009 4:58pm

leitrim lad wrote: »

the chain is the way forward, and i can see in the near future gears being the new chain...

Speaking from a development point of view, both chains and gears are actually going backward ...quite a bit at that.

Timing belts have only be used extensively since the 1980's

gofaster_s13 · 10-04-2009 4:58pm

mick.fr wrote: »

Says who/where? There is a very good reason for not using a belt anymore for the timing.

Whats this reason ??

gofaster_s13 · 10-04-2009 5:04pm

leitrim lad wrote: »

the chain is the way forward, and i can see in the near future gears being the new chain, as belts are to dodgy nowadays

Its generally thought that timing gears are unusable in overhead cam engines as the size of the gears needed to bring drive to the cams would be too big, chains and gears are actually a step backwards in automotive development.

mick.fr · 10-04-2009 5:11pm

gofaster_s13 wrote: »

Whats this reason ??

Heat. Short lifespan.
It has been over 20 years BMW does not use belts anymore for the timing for example.
It also helped improving exhaust levels and fuel efficiency.

I seriously doubt they would be the only ones to have gone this road

Unless you can prove me wrong.

bushy... · 10-04-2009 5:14pm

mick.fr wrote: »

Heat. Short lifespan.
BMW

Fixed your post

gofaster_s13 · 10-04-2009 5:20pm

mick.fr wrote: »

Heat. Short lifespan.
It has been over 20 years BMW does not use belts anymore for the timing for example.
It also helped improving exhaust levels and fuel efficiency.

I seriously doubt they would be the only ones to have gone this road
Unless you can prove me wrong.

How does a chain improve fuel efficiency and emissions

VW make the most technologically advanced light vehicle engines and they still use belts. Belts do not have a short lifespan, they have a set change interval.

mick.fr · 10-04-2009 5:21pm

gofaster_s13 wrote: »

How does a chain improve fuel efficiency and emissions VW make the most technologically advanced light vehicle engines and they still use belts. Belts do not have a short lifespan, they have a set change interval.

Ok dude

mick.fr · 10-04-2009 5:21pm

bushy... wrote: »

Fixed your post

gofaster_s13 · 10-04-2009 5:22pm

mick.fr wrote: »

Ok dude

bushy... · 10-04-2009 5:45pm

gofaster_s13 wrote: »

VW make the most technologically advanced light vehicle engines and they still use belts. Belts do not have a short lifespan, they have a set change interval.

What bit is technologically advanced ? They still use cams .

Dump the cams n throttles and actuate the valves directly. You could then do all sorts of tricks like total control over valve lift , timing and so on .

That'd be a small step forward , lots of advances are just the same old " what can we put in this years brochure " stuff.

gofaster_s13 · 10-04-2009 6:07pm

bushy... wrote: »

What bit is technologically advanced ? They still use cams .

Dump the cams n throttles and actuate the valves directly. You could then do all sorts of tricks like total control over valve lift , timing and so on .

That'd be a small step forward , lots of advances are just the same old " what can we put in this years brochure " stuff.

Not sure how you would dump the throttle as Petrol engines are regulated by air flow but solenoid controlled valves wont happen until a more reliable electrical source is found, 48volts is generally considered to be the minimum necessary which at the moment due to weight and space constraints along with current battery technology cant happen. Of the general motor vehicle manufacturers the VAG group is the the one pushing the boundaries at the moment just look at what they have done to the diesel engine in the last 15 yrs(it pains me to say that as I am not a liker of VW's).

L1011 · 10-04-2009 6:31pm

gofaster_s13 wrote: »

VAG group is the the one pushing the boundaries at the moment just look at what they have done to the diesel engine in the last 15 yrs(it pains me to say that as I am not a liker of VW's).

Chased one step behind Fiat and Bosch?

gofaster_s13 · 10-04-2009 6:44pm

MYOB wrote: »

Chased one step behind Fiat and Bosch?

Fiat and Bosch brought common rail to the light engines there have been many more developments other than common rail

L1011 · 10-04-2009 6:54pm

gofaster_s13 wrote: »

Fiat and Bosch brought common rail to the light engines there have been many more developments other than common rail

It wasn't the sole thing they've done, though.

leitrim lad · 10-04-2009 7:58pm

well firstly common rail engines are a load of sh2t, the greatest waste of money and metal that ever took place on this earth was the common rail engines

another inventive green idea, (common rail engine) its one way of keeping motors off the road, put a common rail engine in them and they will spend the best part of their life in a garage getting fixed, savage way of keeping emmisions down john gormley

and as for the chain and gears it is stepping back in time but is a lot better that depending on a belt that was made by F ix It Again Tomorrow (fiat) that will and has on several occasions snapped leaving the driver stranded,

not many chains snapped yet, and the majority of mercs have a gear ratio, rather than belt

L1011 · 10-04-2009 8:09pm

180,000km between the two JTDs parked up outside here and neither of them has been in the garage for engine problems at any stage.

If you use a common rail engine made by someone else they might not be as reliable... which is probably why nobody tries to make small ones, they just use Fiats one.

Timing belt Vs. Timing chain?

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