Discussion
Thinking about high mileage reliability got me to ponder other indications of wear. Planes use hours, but you could also use no of engibe revolutions as an indicator of lifetime use.
I've just worked out that my 157k mile Jag's engine has done over 600,000,000 revolutions since it was bought. I knew it owuld be a lot, but over half a billion times?! Wow.
Unbelievable how reliable these things are, isn't it?
I've just worked out that my 157k mile Jag's engine has done over 600,000,000 revolutions since it was bought. I knew it owuld be a lot, but over half a billion times?! Wow.
Unbelievable how reliable these things are, isn't it?
I've posted this before, but will do so again. Corvettes from 1953 - 1959 had a total rev counter. So, whilst the idea is an interesting one, it's not a new one. I wonder how many revs a '53 corvette would have done by now!
http://www.howstuffworks.com/1953-corvette.htm
http://www.howstuffworks.com/1953-corvette.htm
st4 said:
If you look after a car, why should it fail. After 100 years of building the things, we should have them off to a fine art.
Because it's a machine containing tens of thousands of parts, sourced from hundreds of different suppliers in dosens of countries, which is then pressed into service in a widely variable operational environment where it may or may not be maintained and is expected to live for well over 100k miles/10 years regardless. Millions are produced and yet so few suffer premature catastrophic failure... HustleRussell said:
Because it's a machine containing tens of thousands of parts, sourced from hundreds of different suppliers in dosens of countries, which is then pressed into service in a widely variable operational environment where it may or may not be maintained and is expected to live for well over 100k miles/10 years regardless. Millions are produced and yet so few suffer premature catastrophic failure...
But it's deigned to be used in that way and built to a specification to allow this.Consider aircraft. They are flown many more miles and have an operational life span over 20years. The components, wiring, etc is of a higher standard to that of car. Very few if any fail because they are designed to work.
Some cars have inherint weaknesses (BMW timing chains on newer N47 engines, swirl flap failures and Mercedes M272 balancer shafts).
Sadly, I think it sad modern cars actually have so many failings.
HustleRussell said:
st4 said:
If you look after a car, why should it fail. After 100 years of building the things, we should have them off to a fine art.
Because it's a machine containing tens of thousands of parts, sourced from hundreds of different suppliers in dosens of countries, which is then pressed into service in a widely variable operational environment where it may or may not be maintained and is expected to live for well over 100k miles/10 years regardless. Millions are produced and yet so few suffer premature catastrophic failure... On the flip side, given the bloating prices of cars these days (German ones in particular), it's not unreasonable to expect 100% reliability within the warranty period.
SuperchargedVR6 said:
On the flip side, given the bloating prices of cars these days (German ones in particular), it's not unreasonable to expect 100% reliability within the warranty period.
Say a manufacturer somehow achieved 100% reliability for the first 3 years, and 99.9% reliability for the 4th year, they'd be crazy to market it as a 3 year warrenty when a 4 year would give them some marketing mileage while not costing them much.st4 said:
HustleRussell said:
Because it's a machine containing tens of thousands of parts, sourced from hundreds of different suppliers in dosens of countries, which is then pressed into service in a widely variable operational environment where it may or may not be maintained and is expected to live for well over 100k miles/10 years regardless. Millions are produced and yet so few suffer premature catastrophic failure...
But it's deigned to be used in that way and built to a specification to allow this.Consider aircraft. They are flown many more miles and have an operational life span over 20years. The components, wiring, etc is of a higher standard to that of car. Very few if any fail because they are designed to work.
Some cars have inherint weaknesses (BMW timing chains on newer N47 engines, swirl flap failures and Mercedes M272 balancer shafts).
Sadly, I think it sad modern cars actually have so many failings.
Not that this is necessarily a sign of quality but comments I regularly hear are that the quality documentation is more extensive in the automotive industry than in some part of the aerospace industry.
RizzoTheRat said:
Because components wear out.
Theres always a need for routine maintaince but I am sorry but my mates E320cdi 05 is rusting, and newer cars have known faults with timing chains (BMWs) and Porsche have the IMS issue and on the Cayenne 4.5V8s the cylinder liners can go at 70k miles.All premature things that kill off cars before they need to die
edc said:
st4 said:
HustleRussell said:
Because it's a machine containing tens of thousands of parts, sourced from hundreds of different suppliers in dosens of countries, which is then pressed into service in a widely variable operational environment where it may or may not be maintained and is expected to live for well over 100k miles/10 years regardless. Millions are produced and yet so few suffer premature catastrophic failure...
But it's deigned to be used in that way and built to a specification to allow this.Consider aircraft. They are flown many more miles and have an operational life span over 20years. The components, wiring, etc is of a higher standard to that of car. Very few if any fail because they are designed to work.
Some cars have inherint weaknesses (BMW timing chains on newer N47 engines, swirl flap failures and Mercedes M272 balancer shafts).
Sadly, I think it sad modern cars actually have so many failings.
Not that this is necessarily a sign of quality but comments I regularly hear are that the quality documentation is more extensive in the automotive industry than in some part of the aerospace industry.
st4 said:
RizzoTheRat said:
Because components wear out.
Theres always a need for routine maintaince but I am sorry but my mates E320cdi 05 is rusting, and newer cars have known faults with timing chains (BMWs) and Porsche have the IMS issue and on the Cayenne 4.5V8s the cylinder liners can go at 70k miles.All premature things that kill off cars before they need to die
Oh. No one.
In that case we have to accept that cars will be built to a quality that allows the person who bought it to be happy enough that he'll replace it with another new one from the same company. And everyone who buys secondhand will just have to accept that not buying new means you don't get to have a say on how durable new cars have to be.
The problem here isn't engineering, it's economics. Once the guys on InvoiceHeads.com have fixed that then the car guys can build the everlasting cars that are technically feasable (but still not optimum because cars that can be regularly serviced and repaired will be lighter, faster and use less fuel, as well as being cheaper).
Anyway, I have a 21 year old Mazda that still works fine, and other than a bit of welding and servicing I'd expect it to last another 21 years. Which isn't bad.
I think a good chunk of the problem is the end user. In the olden days, cars were well looked after because motorists often did their own tinkering and generally knew about mechanical sympathy etc.
These, so many drivers are the sort of brainless mongs you see on the "stupid things non petrolheads say" thread who view cars as white good that need zero maintenance ever and can be consistently thrashed
These, so many drivers are the sort of brainless mongs you see on the "stupid things non petrolheads say" thread who view cars as white good that need zero maintenance ever and can be consistently thrashed
Ozzie Osmond said:
Compare the 35 million times your heart beats each year. That little bit of meat will be heading towards 250,000,000 in a full lifetime!
Ever had it serviced?
No need. It's a living organism so, atomically, it completely replaces everything within 5 years (probably a lot less for a heart) but the atoms in your pistons are still the same as day one.Ever had it serviced?
Ozzie Osmond said:
Compare the 35 million times your heart beats each year. That little bit of meat will be heading towards 250,000,000 in a full lifetime!
Ever had it serviced?
I found myself thinking about that recently. I was talking to my Grandad and I realised that his heart (bless it!) started beating when David Lloyd George was prime minister... It's been going non-stop for over 90 years.Ever had it serviced?
HustleRussell said:
I found myself thinking about that recently. I was talking to my Grandad and I realised that his heart (bless it!) started beating when David Lloyd George was prime minister... It's been going non-stop for over 90 years.
Bet he tells you it stopped when he first saw yer gran 
HustleRussell said:
edc said:
st4 said:
HustleRussell said:
Because it's a machine containing tens of thousands of parts, sourced from hundreds of different suppliers in dosens of countries, which is then pressed into service in a widely variable operational environment where it may or may not be maintained and is expected to live for well over 100k miles/10 years regardless. Millions are produced and yet so few suffer premature catastrophic failure...
But it's deigned to be used in that way and built to a specification to allow this.Consider aircraft. They are flown many more miles and have an operational life span over 20years. The components, wiring, etc is of a higher standard to that of car. Very few if any fail because they are designed to work.
Some cars have inherint weaknesses (BMW timing chains on newer N47 engines, swirl flap failures and Mercedes M272 balancer shafts).
Sadly, I think it sad modern cars actually have so many failings.
Not that this is necessarily a sign of quality but comments I regularly hear are that the quality documentation is more extensive in the automotive industry than in some part of the aerospace industry.
At present the aerospace industry is carefully looking at elements of the automotive quality standards (in particular I know RR have been looking for experience in APQP from the automotive industry)
In terms of manufacture and longevity, variability is the killer. If everything could be made the same it would be easy. Unfortunately, most materials are dug from the ground at some stage, temperature and humidity are never static, multiple same spec. machines are never the same, etc etc.. All these small variations have an impact on the each component which then makes up the end product. The number of 'discussions' I have with our customers about measurement systems is unreal (something the end user would consider a given!). So we can manufacture something (with variation) but then we cannot even bloody agree how to measure the thing... aarrgghhhh!!!!
Just my brief and probably incorrect thoughts and views.....
Mike
Edited by mike9009 on Wednesday 27th March 20:57
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