Discussion
Cam belts are supposed to be quieter than chains. Chains are meant to last the life of the engine, but that depends on you getting the oil changed regularly. Belts are easier to change (comparatively) than chains. Did my first belt change a while back, wasn't that difficult in the end, although I took a few goes to get it right.
Alfa Romeo had a lot of early failures on the 2.0 JTS engine in the 156 (which I've got) so they reduced the interval to 36000 miles from (I think) 72000. It's a good question why belts on some engines/makes last longer, I'd be interested to find out the reason for that.
Alfa Romeo had a lot of early failures on the 2.0 JTS engine in the 156 (which I've got) so they reduced the interval to 36000 miles from (I think) 72000. It's a good question why belts on some engines/makes last longer, I'd be interested to find out the reason for that.
Back in the early 2000's I think I'm correct in saying that some of the Ford Zetec engines had a timing belt interval of 100,000 miles or 10 years. They weren't common to fail prematurely either and I chanced one for almost fifteen years without it letting go.
Where as the current Ford Transits with the (2.0?) diesel engine, they are having big problems with timing belts failing early with no warning.
How things have gone backwards I don't know???
Where as the current Ford Transits with the (2.0?) diesel engine, they are having big problems with timing belts failing early with no warning.
How things have gone backwards I don't know???
Point i am trying to work out is if a alfa romeo does a 1,000 miles and a Vauxhaul does a 1,000 the natural deteriation of rubber is the same which ever the car it is in is irrelevent. I realise that due to poor engineering one might be weaker then the other but why would one be so badly deteriorated that it needed changing and the other can stay in use for another seven years . A cam belt might be a year or two or even older at the time of purchase.
i have probably not wrote the above in clearly but hope everyone understands what i am getting at
i have probably not wrote the above in clearly but hope everyone understands what i am getting at
Matt_E_Mulsion said:
Back in the early 2000's I think I'm correct in saying that some of the Ford Zetec engines had a timing belt interval of 100,000 miles or 10 years. They weren't common to fail prematurely either and I chanced one for almost fifteen years without it letting go.
Where as the current Ford Transits with the (2.0?) diesel engine, they are having big problems with timing belts failing early with no warning.
How things have gone backwards I don't know???
Not just manufacturer or type specific http://prestige-german-engines.co.uk/engine-issues...Where as the current Ford Transits with the (2.0?) diesel engine, they are having big problems with timing belts failing early with no warning.
How things have gone backwards I don't know???
Iirc? The bug eyed Micra had a Renault engine, first sign of chain stretch was the engine management light illuminating misleading diagnosis in to replacing lambda sensors.
An engine no longer with us Ford CVH, Think belt replacement advice was 3 year/36,000mls I heard of some at 9,000 ! But that was often the water pump failing taking the belt out.
I suspect better designs are sacrificed in favour of cost or possibly a certain designers idea is adopted and inherent faults only surface in general use. On the whole I think engines are much better.
It's usually age related, the older the engine design the worse the design is and the belts last less time.
What makes a bad design is:
Tooth profile (there are several).
Width of belt, possibly length too.
Type of tensioner (early ones were fixed which were crap, then we've had spring loaded and oil pressure related ones I think, Alfa V6)
How hot they get, how well protected they are.
Whether they run in the air or through an oil bath (belts).
I think one of the worst designers of belt driven cam engines in the 80s were Fiat/Alfa/Lancia. They produced one engine with a 19mm belt, fixed tens bearing and poor tooth design, they never got anywhere near the 36k they were supposed to.
Then they designed a boxer engine (it's thought Subaru copied it) which the cam belt drove the power steering pump. If you put full lock on when the engine was cold it broke the belt.
What makes a bad design is:
Tooth profile (there are several).
Width of belt, possibly length too.
Type of tensioner (early ones were fixed which were crap, then we've had spring loaded and oil pressure related ones I think, Alfa V6)
How hot they get, how well protected they are.
Whether they run in the air or through an oil bath (belts).
I think one of the worst designers of belt driven cam engines in the 80s were Fiat/Alfa/Lancia. They produced one engine with a 19mm belt, fixed tens bearing and poor tooth design, they never got anywhere near the 36k they were supposed to.
Then they designed a boxer engine (it's thought Subaru copied it) which the cam belt drove the power steering pump. If you put full lock on when the engine was cold it broke the belt.
Matt_E_Mulsion said:
Back in the early 2000's I think I'm correct in saying that some of the Ford Zetec engines had a timing belt interval of 100,000 miles or 10 years. They weren't common to fail prematurely either and I chanced one for almost fifteen years without it letting go.
Where as the current Ford Transits with the (2.0?) diesel engine, they are having big problems with timing belts failing early with no warning.
How things have gone backwards I don't know???
These are wet belts inside the engine like the late 1.8 connects and peugeot puretech engines , rubber and hot oil do not mix well !Where as the current Ford Transits with the (2.0?) diesel engine, they are having big problems with timing belts failing early with no warning.
How things have gone backwards I don't know???
Cam belts* should* be easy to change, the one fitted to Toyota 3.0 litre Diesels is a one hour DIY job the first time you do it (90k interval), don't even need to remove the auxilliary drive belt, no special tools needed, no locking tools, proper timing marks, full quality kit just over £100, all belt drives should be like this.
When a belt is this easy to change i'd rather have one than a chain, which if it needs replacing is usually a massive job.
Part of what makes that particular Toyota belt simple and reliable is that the belt only drives the camshafts, one cam driven by the belt the other cam being geared off the first cam, one tensioner/idler, thats it.
When it all goes wrong leading to early failure is the tortuous routes taken by many (most?) belts, the belt driving all sorts of rubbish it has no place driving ie water pumps, so several idlers involved plus a tensioner...this is poor engineering, timing chains don't drive water pumps there is no earthly reason why a cambelt should be doing so.
When a belt is this easy to change i'd rather have one than a chain, which if it needs replacing is usually a massive job.
Part of what makes that particular Toyota belt simple and reliable is that the belt only drives the camshafts, one cam driven by the belt the other cam being geared off the first cam, one tensioner/idler, thats it.
When it all goes wrong leading to early failure is the tortuous routes taken by many (most?) belts, the belt driving all sorts of rubbish it has no place driving ie water pumps, so several idlers involved plus a tensioner...this is poor engineering, timing chains don't drive water pumps there is no earthly reason why a cambelt should be doing so.
Evoluzione said:
It's usually age related, the older the engine design the worse the design is and the belts last less time.
What makes a bad design is:
Tooth profile (there are several).
Width of belt, possibly length too.
Type of tensioner (early ones were fixed which were crap, then we've had spring loaded and oil pressure related ones I think, Alfa V6)
How hot they get, how well protected they are.
Whether they run in the air or through an oil bath (belts).
I think one of the worst designers of belt driven cam engines in the 80s were Fiat/Alfa/Lancia. They produced one engine with a 19mm belt, fixed tens bearing and poor tooth design, they never got anywhere near the 36k they were supposed to.
Then they designed a boxer engine (it's thought Subaru copied it) which the cam belt drove the power steering pump. If you put full lock on when the engine was cold it broke the belt.
Subaru were building boxer engines before Alfa. What makes a bad design is:
Tooth profile (there are several).
Width of belt, possibly length too.
Type of tensioner (early ones were fixed which were crap, then we've had spring loaded and oil pressure related ones I think, Alfa V6)
How hot they get, how well protected they are.
Whether they run in the air or through an oil bath (belts).
I think one of the worst designers of belt driven cam engines in the 80s were Fiat/Alfa/Lancia. They produced one engine with a 19mm belt, fixed tens bearing and poor tooth design, they never got anywhere near the 36k they were supposed to.
Then they designed a boxer engine (it's thought Subaru copied it) which the cam belt drove the power steering pump. If you put full lock on when the engine was cold it broke the belt.
Boxer engines go back to the earliest engines built, it's an inherently good design philosophy.
Cam belt life can be a function of valve train load and legislation, you often find different markets for the same engine have different replacement schedules.
jsf said:
Evoluzione said:
It's usually age related, the older the engine design the worse the design is and the belts last less time.
What makes a bad design is:
Tooth profile (there are several).
Width of belt, possibly length too.
Type of tensioner (early ones were fixed which were crap, then we've had spring loaded and oil pressure related ones I think, Alfa V6)
How hot they get, how well protected they are.
Whether they run in the air or through an oil bath (belts).
I think one of the worst designers of belt driven cam engines in the 80s were Fiat/Alfa/Lancia. They produced one engine with a 19mm belt, fixed tens bearing and poor tooth design, they never got anywhere near the 36k they were supposed to.
Then they designed a boxer engine (it's thought Subaru copied it) which the cam belt drove the power steering pump. If you put full lock on when the engine was cold it broke the belt.
Subaru were building boxer engines before Alfa. What makes a bad design is:
Tooth profile (there are several).
Width of belt, possibly length too.
Type of tensioner (early ones were fixed which were crap, then we've had spring loaded and oil pressure related ones I think, Alfa V6)
How hot they get, how well protected they are.
Whether they run in the air or through an oil bath (belts).
I think one of the worst designers of belt driven cam engines in the 80s were Fiat/Alfa/Lancia. They produced one engine with a 19mm belt, fixed tens bearing and poor tooth design, they never got anywhere near the 36k they were supposed to.
Then they designed a boxer engine (it's thought Subaru copied it) which the cam belt drove the power steering pump. If you put full lock on when the engine was cold it broke the belt.
Boxer engines go back to the earliest engines built, it's an inherently good design philosophy.
Cam belt life can be a function of valve train load and legislation, you often find different markets for the same engine have different replacement schedules.
Valvetrain load is a valid point though, when FLA went from an 8v engine to a 16v they didn't upgrade the belt. In retrospect unbelievably stupid.
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