ford wet belt engines??

[charlysays]

I always love when people get the rose tinted glasses out, about how modern stuff isn't as good.


We also have far better fuel economy and emissions.
Off course you could go to chain drive which means you need to compromise valve timing to allow for chain wear (belts don't wear, so timing remains the same between replacement).
Or you could go back to side valves, or have enough valve/piston clearance that compression is that poor the volumetric efficiency is horrendous.

There was a reason behind that setup. I can't quite remember the details as it's been several years since I covered it, but IIRC it was to allow faster warmup and a more stable operating temp. The biggest flaw with that engine was the rubbish head gasket, and it was prone to coolant leaks, not the thermostat.

That rubber belt is far more efficient than a chain. It allows more precise valve timing over the lifespan of the belt, as the belt doesn't wear.
And it's not as though timing chains are infallible. I've seen plenty chains fail.


Off course some people would love to go back to the "good old days" of cities turning black due to soot with the smell of hydrocarbons hanging in the air, having to service their car every few thousand miles, always wondering when it'll breakdown next.
Lets remember pre 90s, how many engines ever made it to 80k without needing major work?

New is worse though if you like to be able to repair everything (almost) yourself and/or don't have much to spend on buying a car.
90's was the pinnacle really for reparability, long term reliability and rust resistance. After 2000 it seems like car makers have deliberately tried to make cars a disposable item which are not likely to even survive long enough to become classics. It's still fairly easy to find 90s Peugeots for example with no visible rust and few if any structural problems, still passing MOTs with huge mileages. With many 90s engines it was possible to de-electrickery them (I remember binning the lucas IP on my 1.9TD peugeot and fitting a bosch IP which just need a switched 12v live to open the stop solenoid to run, nothing else- it even kept going when the alternator died!). On my C250 TD I've pretty much made the engine standalone now, it still runs an ECU (of which I've got several spare immo off ones) but with all extraneous stuff (electronic turbo control, etc) removed including the immobiliser.

I think there's a compromise to be made between emissions/ modern convenience and reparability- currently there's almost no balance at all with many cars. Even if the engine needs all sorts of emission control on it there's no need to have the indicators controlled by a computer, or engineer it so it's a nightmare to do relatively basic routine stuff like cambelts or timing chains. We have all the benefits of modern advances but it's all ruined by throw away culture/ deliberate obsolescence.

 

[Morris]

Wifey put 250k miles on her old Golf MK3 1.9. It was the aaz engine and only had cam belt, tyres and a battery. An accidental trip into a flood killed it, don't think anything else would.

 

[hermetic]

I always love when people get the rose tinted glasses out, about how modern stuff isn't as good.


We also have far better fuel economy and emissions.
Off course you could go to chain drive which means you need to compromise valve timing to allow for chain wear (belts don't wear, so timing remains the same between replacement).
Or you could go back to side valves, or have enough valve/piston clearance that compression is that poor the volumetric efficiency is horrendous.

There was a reason behind that setup. I can't quite remember the details as it's been several years since I covered it, but IIRC it was to allow faster warmup and a more stable operating temp. The biggest flaw with that engine was the rubbish head gasket, and it was prone to coolant leaks, not the thermostat.

That rubber belt is far more efficient than a chain. It allows more precise valve timing over the lifespan of the belt, as the belt doesn't wear.
And it's not as though timing chains are infallible. I've seen plenty chains fail.


Off course some people would love to go back to the "good old days" of cities turning black due to soot with the smell of hydrocarbons hanging in the air, having to service their car every few thousand miles, always wondering when it'll breakdown next.
Lets remember pre 90s, how many engines ever made it to 80k without needing major work?

1)Fuel economy does not come from rubber belts

2) rubber belts are less efficient than chains because they need more tension and tension =friction
3) belts do wear, and when they are loose they fail.
4) there is no need to comprimise valve timing as chains wear (very slowly as they are oil immersed) because the chain is tensioned by an oil pressure fed tensioner, also expensive to make.
5) I can remember the setup, the thermostat was low down behind the engine, and the upper half of the engine was getting towards overheating before enough heat got to the thermostat to open it. When I first saw the new engine I said they would have severe cooling problems. They did. They lasted about 35000 to 40000 before they failed, and by this time so much damage had been done by the uneven heating of an all aluminium engine that they were BER. Removing the thermostat(not easy) cured the problem, but there was a (very small) price to pay in fuel economy, what was needed was not a quick warm up But an EVEN warm up
A Jaguar XK enghine would get to 100,000 before the timing chains needed ADJUSTING!
The rubber belts, as I said are used for one reason only, the pulleys can be cast finished, and only require a bore and a keyway, chainwheels are very expensive to machine, and chains are also expensive to make. toothed belts only advantage is cheapness! It has no bearing whatever on fuel economy or pollution, it is just MUCH cheaper!
Phil

 

[Ubique]

Borg Warner don't agree WRT wet belts vs. chains

https://cdn.borgwarner.com/docs/default-source/default-document-library/2014_whitepaper_timing-chains-or-belts_en.pdf?sfvrsn=580bcd3c_14

There is also the consideration of weight, negligible on larger engines but a consideration on smaller ones, and as you said, chains & associated parts are much more expensive.

 

[PhillipM]

Also they're way quieter for NVH

 

[hermetic]

Borg Warner don't agree WRT wet belts vs. chains

https://cdn.borgwarner.com/docs/default-source/default-document-library/2014_whitepaper_timing-chains-or-belts_en.pdf?sfvrsn=580bcd3c_14

There is also the consideration of weight, negligible on larger engines but a consideration on smaller ones, and as you said, chains & associated parts are much more expensive.

Borg warner says that the efficiency of the chain is better than a dry belt and about the same as a wet belt. The rule with a timing chain is that if you can hear it at all, it needs adjusting! A chain running in an oil immersed system will last a huge mileage, also note that the BW test is not for belt failure, and is done on their"motored engine
friction test stand" not under running conditions, the engine is driven by an electric motor

 

[hermetic]

Also they're way quieter for NVH

you cannot hear a timing chain inside an engine unless it needs adjusting, these were all the manufacturers tales that were used to convince the gullible public that "belts are better"

 

[Ubique]

Borg warner says that the efficiency of the chain is better than a dry belt and about the same as a wet belt. The rule with a timing chain is that if you can hear it at all, it needs adjusting! A chain running in an oil immersed system will last a huge mileage, also note that the BW test is not for belt failure, and is done on their"motored engine
friction test stand" not under running conditions, the engine is driven by an electric motor

Nope, chains do fail, become noisy and lose timing relationships due to wear - they're also a relatively heavy system so carry a weight penalty vs. the friction penalty of dry belts. Also, chain manual adjustment is very old tech - a bit like Grandad 'doing his tappets' on a Saturday afternoon. These days (post turn of the century) if you can hear a chain - which I often do, it needs replacing. I've worked for manufacturers and dealers of manufacturers where there is a preference for chains, dry belts, wet belts or a mix. The engines with belts were/are by far the better running and more refined ones - again, going on engines from the current century. Probably the worst performing and most repaired chain-driven engine IMO is the Audi 3.0TDI.

I assume by 'gullible' you mean 'doesn't agree with hermetic'?

 

[PhillipM]

you cannot hear a timing chain inside an engine unless it needs adjusting, these were all the manufacturers tales that were used to convince the gullible public that "belts are better"

Of course you can.
I can tell you if an engine is chain or belt just by listening to it most of the time.

NVH is a massive driver on anything automotive these days, because it lets you upsell your cars as much higher quality than they are.

You also have the massive issue of chain tensioning guides wearing and breaking these days - one of which I'm right in the middle of just now on a Merc E-Class.

 

[badabec]

The Citroen DS had a duplex chain at the rear of the engine since 1955. This is because the car is mid-engined with the gearbox at the front.
When they were scrap value, a cheap way to change the chain was to go in through the bulkhead. Mine had that done. The 2.5mm steel bulkhead was patched up with aluminium sheet pop riveted into place.

 

[Ubique]

...

You also have the massive issue of chain tensioning guides wearing and breaking these days - one of which I'm right in the middle of just now on a Merc E-Class.

OM654? Autostop is the biggest contributor to this, check the cam followers for wear in the roller bearings - also puts undue stress on the chain & guides.

 

[Barking Mat]

I always love when people get the rose tinted glasses out, about how modern stuff isn't as good.


We also have far better fuel economy and emissions.
Off course you could go to chain drive which means you need to compromise valve timing to allow for chain wear (belts don't wear, so timing remains the same between replacement).
Or you could go back to side valves, or have enough valve/piston clearance that compression is that poor the volumetric efficiency is horrendous.

There was a reason behind that setup. I can't quite remember the details as it's been several years since I covered it, but IIRC it was to allow faster warmup and a more stable operating temp. The biggest flaw with that engine was the rubbish head gasket, and it was prone to coolant leaks, not the thermostat.

That rubber belt is far more efficient than a chain. It allows more precise valve timing over the lifespan of the belt, as the belt doesn't wear.
And it's not as though timing chains are infallible. I've seen plenty chains fail.


Off course some people would love to go back to the "good old days" of cities turning black due to soot with the smell of hydrocarbons hanging in the air, having to service their car every few thousand miles, always wondering when it'll breakdown next.
Lets remember pre 90s, how many engines ever made it to 80k without needing major work?

Yeah, but....

A toothed timing belt dry is recommended to be changed at 5 years irrespective of mileage. Immersed in oil ???

And that's for the life of the engine ???

 

[Ubique]

Depends upon the engine - also a wet belt has a different contruction to a dry belt, hence why an oil leak can destroy a dry belt (clue is in the name )
A lot of dry belt engines have recommended change intervals of 150k or 10 years, it used to be five years in the 80's & 90's for CVH engines and whatever the Vauxhall version was at the time.

 

[Keithmac]

178,000 on a Mondeo 2.0TDCi. Never had the wet belt changed.

Waiting for the big day.....

It's a dry belt on the 2l Diesels.

 

[dobbslc]

The official Vauxhall CDTI diesel engine timing belt interval was something like 80k, lots failed at 45k due to water pump failure taking out the belts.
The belt change interval in the same engine in an Alfa Romeo was 40k

 

[Ubique]

The official Vauxhall CDTI diesel engine timing belt interval was something like 80k, lots failed at 45k due to water pump failure taking out the belts.
The belt change interval in the same engine in an Alfa Romeo was 40k

Devils Advocate: the belt would have lasted if it wasn't for the specification of the coolant pump....

And 40k on an Alfa is aspirational the body would let go of the powertrain long before that!

 

[m_c]

1)Fuel economy does not come from rubber belts

2) rubber belts are less efficient than chains because they need more tension and tension =friction
3) belts do wear, and when they are loose they fail.
4) there is no need to comprimise valve timing as chains wear (very slowly as they are oil immersed) because the chain is tensioned by an oil pressure fed tensioner, also expensive to make.
5) I can remember the setup, the thermostat was low down behind the engine, and the upper half of the engine was getting towards overheating before enough heat got to the thermostat to open it. When I first saw the new engine I said they would have severe cooling problems. They did. They lasted about 35000 to 40000 before they failed, and by this time so much damage had been done by the uneven heating of an all aluminium engine that they were BER. Removing the thermostat(not easy) cured the problem, but there was a (very small) price to pay in fuel economy, what was needed was not a quick warm up But an EVEN warm up
A Jaguar XK enghine would get to 100,000 before the timing chains needed ADJUSTING!
The rubber belts, as I said are used for one reason only, the pulleys can be cast finished, and only require a bore and a keyway, chainwheels are very expensive to machine, and chains are also expensive to make. toothed belts only advantage is cheapness! It has no bearing whatever on fuel economy or pollution, it is just MUCH cheaper!
Phil

1) Improved valve timing contributes to fuel economy, which "rubber" belts help due to not needing to allow for wear
2) Efficiency in the actual timing transmission is negligible in terms of engine efficiency.
3) The wear on toothed belts is negligible when compared with a worn timing chain.
4) You really don't get how chains wearing affect valve timing do you? There are belt setups with fixed tensioners, as they don't need any wear compensation over the life of the belt. Try that with a chain, and it'll be rattling very quickly.


You do realise most modern mass produced simplex chain sprockets are stamped, not machined, and probably cost less than an equivalent toothed pulley?

 

[PhillipM]

Or just sintered, the Merc ones are, with far less material than a pulley.

 

[m_c]

Or just sintered, the Merc ones are, with far less material than a pulley.

I'd forgotten about sintered.
It's quite common for toothed pulleys.

 

[bricol]

Sometimes, as a design engineer, using belts, chains, cogettes, big cogs, anti-backlash cogs, dry, spray/splash/immersed lubricated . . . sometimes I just have to keep quiet when I hear/read some things people believe

I might have to point my colleague, a lot further on the spectrum, to this forum . . . I think his keyboard would combust though, as he put people right

Anyway, my 07 plate Alfa on 100,000 miles is still looking good, despite the GM V6 in the front - the one with three timing chains in it, the one they had several goes at stopping the chains stretching excessively - Cadillac managed to fix the misfire it caused in their cars under warranty in not many minutes flat . . . rumour has it they reprogrammed the ECU to accept wider variances between all the sensors - it lost power/economy etc, but at least it didn't misfire and through error codes up for fun. I had to pull the engine out to get to the failed Japanese bearing in the German add-on box to send power to the back wheels, so took the opportunity to change all of them then, complete with guides, tensions, sprockets . . . what fun that was.