Dangers of DIY car brake maintenance

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Cowsham
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Re: Dangers of DIY car brake maintenance

Post by Cowsham »

Hybrids are much too complex and when the oil runs out will be as redundant as the complex diesels they replaced. Fully electric is the way I think. When the graphene battery tech arrives that will change everything for the better.

I might be biased as my electric bike build is finished and I can cook up some wood alcohol for my old vw's :lol:
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francovendee
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Re: Dangers of DIY car brake maintenance

Post by francovendee »

I too have driven many thousand miles in old bangers. A contact with a local scrappy supplied me with cars that still had an MOT but were very worn and tatty.
I've had Rovers, Triumphs and numerous Austins and one Fiat. I was offered a Citroen but decided it was just too far gone.
The best of them was a 1500 Austin Maxi; Lousy gear change but nothing went wrong. It even passed another MOT needing only attention to the hand brake. The hatchback style made it great for family camping holidays.
I see the prices these old cars are fetching today and realise if I'd managed to keep all of them I'd be very wealthy man today.
In those days it was normal to have to regularly tinker with them to ensure it kept going.
I still have the interest in these 'classic' cars but value the reliability of our 8 year old Yaris.
Jdsk
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Re: Dangers of DIY car brake maintenance

Post by Jdsk »

Jdsk wrote: 18 Aug 2022, 4:55pm
Mick F wrote: 18 Aug 2022, 4:43pm
Biospace wrote: 17 Aug 2022, 1:17pm Yes, chain cam, not pushrod. I think all the Prius models are chain, also.
Wrong.

The Toyota hybrid engine has no cam belt, no fan belt, no chains, no nothing.
The engine valves are electrically operated with computer controlled variable timing as is the ignition, and the water pump and brake servo are electric too.
There are various different IC engines used in Toyota hybrids.

Several use electrical modification of the valve timing, but that's different from fully electrical actuation.

Which engine (or model, capacity and year) uses fully electrical actuation?
In the absence of an answer we can look at Mick F's own Toyota Yaris hybrid. That's a 2014 XP130 1.5 hybrid.
viewtopic.php?p=1622508&hilit=xp130#p1622508

The engine in those is the 1NZ-FXE. That uses a chain to drive the camshafts.
https://en.wikipedia.org/wiki/Toyota_NZ_engine#1NZ-FXE

The variable valve timing was VVT-i. That's a mechanical system driven by oil pressure. (Toyota did later use electrically driven variation, but that's still quite different from fully electrical actuation of the valves.)
https://en.wikipedia.org/wiki/VVT-i

Jonathan
Jdsk
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Re: Dangers of DIY car brake maintenance

Post by Jdsk »

Biospace wrote: 18 Aug 2022, 6:01pm
Mick F wrote: 18 Aug 2022, 4:43pm
Biospace wrote: 17 Aug 2022, 1:17pm Yes, chain cam, not pushrod. I think all the Prius models are chain, also.
Wrong.

The Toyota hybrid engine has no cam belt, no fan belt, no chains, no nothing.
The engine valves are electrically operated with computer controlled variable timing as is the ignition, and the water pump and brake servo are electric too.
...
Their top ends were driven by chains up to the point my knowledge drops off in that case - thanks for the correction!

I'm aware there is a new breed of Toyota engine with (possibly hydraulic and) electrical valve timing control, different swirl tech etc. but didn't realise they'd mechanically decoupled the crank from the cam. Long overdue, camshafts would have gone out long ago were it not for their efficiency and reliability compared with what used to be the alternative.
...
You were right. They hadn't. Details in previous post.

Jonathan
DanZac
Posts: 17
Joined: 22 Aug 2019, 6:43am

Re: Dangers of DIY car brake maintenance

Post by DanZac »

Jdsk wrote: 19 Aug 2022, 9:14am
Jdsk wrote: 18 Aug 2022, 4:55pm
Mick F wrote: 18 Aug 2022, 4:43pm Wrong.

The Toyota hybrid engine has no cam belt, no fan belt, no chains, no nothing.
The engine valves are electrically operated with computer controlled variable timing as is the ignition, and the water pump and brake servo are electric too.
There are various different IC engines used in Toyota hybrids.

Several use electrical modification of the valve timing, but that's different from fully electrical actuation.

Which engine (or model, capacity and year) uses fully electrical actuation?
In the absence of an answer we can look at Mick F's own Toyota Yaris hybrid. That's a 2014 XP130 1.5 hybrid.
viewtopic.php?p=1622508&hilit=xp130#p1622508

The engine in those is the 1NZ-FXE. That uses a chain to drive the camshafts.
https://en.wikipedia.org/wiki/Toyota_NZ_engine#1NZ-FXE

The variable valve timing was VVT-i. That's a mechanical system driven by oil pressure. (Toyota did later use electrically driven variation, but that's still quite different from fully electrical actuation of the valves.)
https://en.wikipedia.org/wiki/VVT-i

Jonathan
Thanks for clearing that up, I almost got excited at the thought of fully decoupled engine drive trains, and then my engineers brain kicked in and started considering the problems with the idea.

In an interference valve train engine I can only see full electronic timing control as a recipe for disaster, your just opening things up for an entire new world of costly failure modes. At least with VVT your only altering the timing slightly, not fully controlling valve opening and closing etc.

likewise, as far as I can see, the only real advantage of chain driven cams over belt, is the longer service intervals. I would also suspect that you don't hear of many chain failures as they tend to sound like a bag of spanners prior to failing, so people tend to do something about it, where as a belt tends to run silently until it fails, so people ignore the replacement advice and then wonder why they fail. (Says the man that's just rebuilt and engine due to belt failure!)
A dull read for a rainy day - https://pperratt.weebly.com/
Jdsk
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Joined: 5 Mar 2019, 5:42pm

Re: Dangers of DIY car brake maintenance

Post by Jdsk »

DanZac wrote: 19 Aug 2022, 10:40amIn an interference valve train engine I can only see full electronic timing control as a recipe for disaster, your just opening things up for an entire new world of costly failure modes. At least with VVT your only altering the timing slightly, not fully controlling valve opening and closing etc.
Camless engines in stationary units and cars... but not in production cars!
https://en.wikipedia.org/wiki/Camless_piston_engine

Jonathan
Biospace
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Joined: 24 Jun 2019, 12:23pm

Re: Dangers of DIY car brake maintenance

Post by Biospace »

Jdsk wrote: 19 Aug 2022, 9:17am
You were right. They hadn't. Details in previous post.

Jonathan

Perhaps MickF has been talking to a salesman? I think there might be a (Otto cycle) car with valves operated without a camshaft, but it's very expensive and I can't spell its name without googling! I seem to remember when Lotus tried this in the 80s, there was a significant energy loss in doing so. Whenever I consider the energy required in operating valves at a few thousand rpm I can't help but be reminded of the wonderful simplicity and efficiencies of the two-stroke engine.

DanZac wrote: 19 Aug 2022, 10:40am
I almost got excited at the thought of fully decoupled engine drive trains, and then my engineers brain kicked in and started considering the problems with the idea.

In an interference valve train engine I can only see full electronic timing control as a recipe for disaster, your just opening things up for an entire new world of costly failure modes. At least with VVT your only altering the timing slightly, not fully controlling valve opening and closing etc.

likewise, as far as I can see, the only real advantage of chain driven cams over belt, is the longer service intervals. I would also suspect that you don't hear of many chain failures as they tend to sound like a bag of spanners prior to failing, so people tend to do something about it, where as a belt tends to run silently until it fails, so people ignore the replacement advice and then wonder why they fail. (Says the man that's just rebuilt and engine due to belt failure!)

Renault used to make engines which suffered from rattling chains, not helped by their mounting engines behind the gearbox with the chain up against the bulkhead. Rather than take the engine and box out, frustrated owners would cut access ports from the inside of the car...

The engineer's way of driving a camshaft is to use pinions, but makers see this as too costly and owners as too noisy.
Last edited by Biospace on 19 Aug 2022, 11:08am, edited 1 time in total.
Biospace
Posts: 2008
Joined: 24 Jun 2019, 12:23pm

Re: Dangers of DIY car brake maintenance

Post by Biospace »

Cowsham wrote: 19 Aug 2022, 8:28am Hybrids are much too complex and when the oil runs out will be as redundant as the complex diesels they replaced. Fully electric is the way I think. When the graphene battery tech arrives that will change everything for the better.

I might be biased as my electric bike build is finished and I can cook up some wood alcohol for my old vw's :lol:

They're a useful stop gap until battery only takes over, which it very likely will, possibly with 'trolley bus' or inductive charging for lane 1 of busy motorways for HGVs. Whose loads should be carried by railway.

I'm a great believer in reducing our consumption rather than just concentrating on what sort of pollution we make, so for every car to be lumping around a massively heavy battery which can take it 300 miles or more does not make any sense to me. It also gives the maker the ability to accelerate the vehicle stupidly quickly. I forget the precise figures, but 95% of all road journeys are very short indeed.

Mass is the primary efficiency killer in almost every journey by road. It does appear heavy electric power is here to say for the motor car (cheap to source components and the pollution is a long way away) - hydraulic motors are 4 or 5 times lighter and the regen side of things is more efficient, but that's another story, the car has adopted what plenty have suggested is questionable technology many times before. However, the beauty of a hybrid if engineered for efficiency (rather than having a huge, fast 4x4 which escapes the LEZ charges) is that it's possible to have a lightweight vehicle with high range and negligible emissions even with the ICE running.

One efficiency after another results as weight is lost, batteries which power a hybrid today in the urban environment for 15 or 20 miles could power a vehicle half the weight for 40 miles. Or the batteries could be less than half the mass and take you 20 miles. Running as a generator out of town, a lightweight engine producing enough power as a generator to travel at 65mph could be tuned to produce very low emissions, overall lower than for a vehicle twice the mass powered by battery only.

Liquid fuel for a highly efficient hybrid vehicle can be produced with excess renewable energy, storing it between periods of excess wind and sun is not a huge problem. On the other hand, very heavy battery vehicles consume more energy on account of their mass, through excess tyre wear as well as raw materials in manufacture and energy consumption in use. Are we going to carry on building more and more nuclear power stations to match demand?

Remember, the electric car seems more efficient than it really is because the cost of the inefficiencies in making the energy are included in the (low tax) price, whereas with the ICE the user bears the cost of these inefficiencies on top of the cost (heavily taxed - typically 65%) of the fuel. In some respects, the EV is only repeating our mistakes of the past, pushing the source of pollution so far away we can't see it. Except that with 8 or 9 billion people and more all wanting to live a life of luxury, that's no longer possible.
pete75
Posts: 16370
Joined: 24 Jul 2007, 2:37pm

Re: Dangers of DIY car brake maintenance

Post by pete75 »

Jdsk wrote: 19 Aug 2022, 10:52am
DanZac wrote: 19 Aug 2022, 10:40amIn an interference valve train engine I can only see full electronic timing control as a recipe for disaster, your just opening things up for an entire new world of costly failure modes. At least with VVT your only altering the timing slightly, not fully controlling valve opening and closing etc.
Camless engines in stationary units and cars... but not in production cars!
https://en.wikipedia.org/wiki/Camless_piston_engine

Jonathan
Camless engines have been available for years, they called two-strokes.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
Jdsk
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Joined: 5 Mar 2019, 5:42pm

Re: Dangers of DIY car brake maintenance

Post by Jdsk »

Biospace wrote: 19 Aug 2022, 11:02amI think there might be a (Otto cycle) car with valves operated without a camshaft, but it's very expensive and I can't spell its name without googling! I seem to remember when Lotus tried this in the 80s, there was a significant energy loss in doing so. Whenever I consider the energy required in operating valves at a few thousand rpm I can't help but be reminded of the wonderful simplicity and efficiencies of the two-stroke engine.
Koenigsegg?

They did some research on camless engines, but I haven't heard anything recently.
https://en.wikipedia.org/wiki/Koenigsegg

Jonathan
Biospace
Posts: 2008
Joined: 24 Jun 2019, 12:23pm

Re: Dangers of DIY car brake maintenance

Post by Biospace »

Jdsk wrote: 19 Aug 2022, 11:08am
Biospace wrote: 19 Aug 2022, 11:02amI think there might be a (Otto cycle) car with valves operated without a camshaft, but it's very expensive and I can't spell its name without googling! I seem to remember when Lotus tried this in the 80s, there was a significant energy loss in doing so. Whenever I consider the energy required in operating valves at a few thousand rpm I can't help but be reminded of the wonderful simplicity and efficiencies of the two-stroke engine.
Koenigsegg?

They did some research on camless engines, but I haven't heard anything recently.
https://en.wikipedia.org/wiki/Koenigsegg

Jonathan

That's the word. I can spell 'Tiny Friendly Giant' though. The last I remember hearing was that it was in a car, but still in extended development.
pete75
Posts: 16370
Joined: 24 Jul 2007, 2:37pm

Re: Dangers of DIY car brake maintenance

Post by pete75 »

DanZac wrote: 19 Aug 2022, 10:40am
I almost got excited at the thought of fully decoupled engine drive trains, and then my engineers brain kicked in and started considering the problems with the idea.

In an interference valve train engine I can only see full electronic timing control as a recipe for disaster, your just opening things up for an entire new world of costly failure modes. At least with VVT your only altering the timing slightly, not fully controlling valve opening and closing etc.

likewise, as far as I can see, the only real advantage of chain driven cams over belt, is the longer service intervals. I would also suspect that you don't hear of many chain failures as they tend to sound like a bag of spanners prior to failing, so people tend to do something about it, where as a belt tends to run silently until it fails, so people ignore the replacement advice and then wonder why they fail. (Says the man that's just rebuilt and engine due to belt failure!)
My Alfa 75 Twin Spark had variable valve timing back in the late eighties. Seemed to work well as it had the most powerful non turbo 2 litre engine on the market at the time yet it pulled well from bugger all revs. Cam chain was two row, a similar size to a 650 Bonneville primary chain. Never any problems with that. Great car, brilliant engine.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
User avatar
Cowsham
Posts: 4963
Joined: 4 Nov 2019, 1:33pm

Re: Dangers of DIY car brake maintenance

Post by Cowsham »

Biospace wrote: 19 Aug 2022, 11:03am
Cowsham wrote: 19 Aug 2022, 8:28am Hybrids are much too complex and when the oil runs out will be as redundant as the complex diesels they replaced. Fully electric is the way I think. When the graphene battery tech arrives that will change everything for the better.

I might be biased as my electric bike build is finished and I can cook up some wood alcohol for my old vw's :lol:

They're a useful stop gap until battery only takes over, which it very likely will, possibly with 'trolley bus' or inductive charging for lane 1 of busy motorways for HGVs. Whose loads should be carried by railway.

I'm a great believer in reducing our consumption rather than just concentrating on what sort of pollution we make, so for every car to be lumping around a massively heavy battery which can take it 300 miles or more does not make any sense to me. It also gives the maker the ability to accelerate the vehicle stupidly quickly. I forget the precise figures, but 95% of all road journeys are very short indeed.

Mass is the primary efficiency killer in almost every journey by road. It does appear heavy electric power is here to say for the motor car (cheap to source components and the pollution is a long way away) - hydraulic motors are 4 or 5 times lighter and the regen side of things is more efficient, but that's another story, the car has adopted what plenty have suggested is questionable technology many times before. However, the beauty of a hybrid if engineered for efficiency (rather than having a huge, fast 4x4 which escapes the LEZ charges) is that it's possible to have a lightweight vehicle with high range and negligible emissions even with the ICE running.

One efficiency after another results as weight is lost, batteries which power a hybrid today in the urban environment for 15 or 20 miles could power a vehicle half the weight for 40 miles. Or the batteries could be less than half the mass and take you 20 miles. Running as a generator out of town, a lightweight engine producing enough power as a generator to travel at 65mph could be tuned to produce very low emissions, overall lower than for a vehicle twice the mass powered by battery only.

Liquid fuel for a highly efficient hybrid vehicle can be produced with excess renewable energy, storing it between periods of excess wind and sun is not a huge problem. On the other hand, very heavy battery vehicles consume more energy on account of their mass, through excess tyre wear as well as raw materials in manufacture and energy consumption in use. Are we going to carry on building more and more nuclear power stations to match demand?

Remember, the electric car seems more efficient than it really is because the cost of the inefficiencies in making the energy are included in the (low tax) price, whereas with the ICE the user bears the cost of these inefficiencies on top of the cost (heavily taxed - typically 65%) of the fuel. In some respects, the EV is only repeating our mistakes of the past, pushing the source of pollution so far away we can't see it. Except that with 8 or 9 billion people and more all wanting to live a life of luxury, that's no longer possible.
Hydraulic motors in cars?

I never understood why it is more efficient to change chemical energy into mechanical/and heat energy and then into electrical energy to charge a battery, ( chemical stored energy into the battery) and then back into mechanical energy to drive the wheels of a hybrid.

As I said above the hybrid yaris on the spec sheet from Toyota themselves said 47MPG while the 1.3 petrol ( T spirit ) said 55MPG from memory -- which left me wondering why anyone would buy the hybrid when the 1.3 was faster, a bigger boot space, much less complex and more economical on fuel.
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Jdsk
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Joined: 5 Mar 2019, 5:42pm

Re: Dangers of DIY car brake maintenance

Post by Jdsk »

Cowsham wrote: 19 Aug 2022, 11:46am I never understood why it is more efficient to change chemical energy into mechanical/and heat energy and then into electrical energy to charge a battery, ( chemical stored energy into the battery) and then back into mechanical energy to drive the wheels of a hybrid.
It comes from a combination of factors including the weird but familiar operating envelope of piston engines, the many different conditions under which road cars operate, and the ability to incorporate regenerative braking.

If you only think of operating in a single steady state there is no gain of "efficiency".

...

But I expect us to look back on hybrid ICEs in road cars as a complicated temporary fix, rather like the final flourish of piston engines in high powered aircraft with their combination of ram, turbo and superchargers, compounding, exhaust thrust, cooling expansion thrust, water injection and afterburning.

Jonathan
pete75
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Joined: 24 Jul 2007, 2:37pm

Re: Dangers of DIY car brake maintenance

Post by pete75 »

Jdsk wrote: 19 Aug 2022, 12:01pm
Cowsham wrote: 19 Aug 2022, 11:46am I never understood why it is more efficient to change chemical energy into mechanical/and heat energy and then into electrical energy to charge a battery, ( chemical stored energy into the battery) and then back into mechanical energy to drive the wheels of a hybrid.
It comes from a combination of factors including the weird but familiar operating envelope of piston engines, the many different conditions under which road cars operate, and the ability to incorporate regenerative braking.

If you only think of operating in a single steady state there is no gain of "efficiency".

...

But I expect us to look back on hybrid ICEs in road cars as a complicated temporary fix, rather like the final flourish of piston engines in high powered aircraft with their combination of ram, turbo and superchargers, compounding, exhaust thrust, cooling expansion thrust, water injection and afterburning.

Jonathan
In the UK they're probably more to do with BIK taxation on company cars.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
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