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  1. #21
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    Default Re: Questionable engine designs

    Quote Originally Posted by mullerza View Post
    Engineers very seldom get a completely clean sheet to design an engine, invariably there is some carry over or parts sharing from other engines to save design and manufacturing costs. Seen in isolation something may look stupid (and possibly is - engineers also screw up) but more likely it was a compromise between cost/time both in design and manufacturing.

    Also consider when you are making hundreds of thousands of a component even a small cost saving adds up, so if you can save $10 by casting a part in plastic rather aluminium and you make 100 000 of them a year thats $1mil saved. Me and you looking at the piece of plastic on our car would think why would they try and save $10 on a car costing so much but we dont see the big picture.

    Sometimes things do just get a bit silly, we had a thermostat failure on one of the chev utilities at work and I was amazed to see them stripping the cam pulley and cambelt off as the thermostat housing sit behind it on the engine.

    And then having to drop the engine and gearbox on the Q7 so they could replace a boost pipe, but thats more a packaging issue in the chassis than engine design fault
    Mullerza raises a good point here, its an element within Operations Management. However, the concept was based on continuous improvement of products, the search for part commonality, fewer parts in components and so on. There are few manufacturers today who use a 20 or 30 yo engines for instance and continuously improve it, most, I am guessing, are new designs to meet regulations and efficiency goals.

    When it comes to serviceability, modern approaches are lacking and the problem is shifted to the dealer/owner. When LR launched the D3 (I think it was the D3) and I saw that the body had to removed to replace a belt at the back of the engine I though, Nah!
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  2. #22
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    Default Re: Questionable engine designs

    Quote Originally Posted by Francois Theron View Post
    I have at times posted here on some very questionable engine designs where a stupid little oversight can be very expensive in the long run. Fore example the flap valves in the intake manifolds of BMW and Toyotas causing complete engine failure when it breaks.

    Yesterday I watched a video of the Ford 3.5 V6 Eco twin turbo engine being stripped. A very nice engine from a technical point except for one monumental slip up. The waterpump sits inside the timing cover! And although it does have a weep hole to the outside, according to the guy doing the dismantling, the majority of failures on these engines in the US are due to the waterpump leaking and water running straight into the sump.

    I have seen countless similar examples over the years and stand absolutely amazed that the designers could not foresee the potential problem!
    Francois I agree 100%. Have questioned many of designs, design features, component placement and layouts of many engines.
    Have stand back and look many times a these type of things. I sometimes wish to have the designer next to me to explain his way of thinking or doing.

    I think a few things that one should keep in mind that contribute to this topic. First we must admit that motors vehicles have come a long way and are high tech items these days. Also they have become sort of disposable. Vehicles are designed to fulfill a certain lifespan. Think that most new cars will see a 100k km these days without any major or even minor repairs other than services.

    In the old days engineers were involved in his design until the day it left the floor. On the many projects I have done lately I have found that the newer generation engineers is less hands on. Our whole new high tech way of living contribute to that. He can do his design on computer, model it and even subjected it to modeling tests with out even leaving his office. Even strength and structure tests can be modeled. Features that save lots of time and money. In person I think many designs are way better than in the past. Also like many have pointed out in the thread they are restricted by budgets, time lines and even limited lifespan of the product. I sometimes get the idea that many things even engines were designed to be chuck away and replace with new rather than being repaired.

    Think a factor also mentioned is the test phase of engines and components. Many manufacturers uses accelerated test methods to save time.
    Like the simple heater pipe connection on the 4.5 engine you have pointed out. It will last a full 500k km of inhouse testing on a test bench running for hours non stop. That same rubber component will see life in a vehicle that only cover 200k km in 10 years. Clearly exceeding the life span of rubber but not the other tested components. The Ecoboost engine you mentioned will probable never had a failure during testing. Add time and you will see seals fail. Failures like this can even being the cause of a mechanic that put in wrong spec antifreeze. Then suddenly it is a poor design because it allows coolant to seep into the engine oil and can ruin engine. The designer clearly does not take poor maintenance in account. Which he does not need too in my example as he design his water pump with in the frame of rules

    I get the cold shivers with the new law that will allow any workshop to service vehicles in the future. I do not think many people realize how many vehicle specific training technicians undergo on vehicles to be able to fulfill their task in a dealer service environment.

    Think that me and you and other guys that get our hands dirty have a look at these things from a more practical angle. We question these designs with many years of experience and practical doing. I still want to meet that little Jap that decided a starter motor should go under the intake manifold of a v8 engine. Sal graag vir hom in plein boere Afrikaans wil sÍ dit is `n ### idee.

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  4. #23
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    Default Re: Questionable engine designs

    Quote Originally Posted by Francois Theron View Post
    Darron I have been asked this question before (might even have been you). No I am not aware of a con rod breaking issue on those engines. The studs breaking due to wrong/insufficient coolant additive yes.

    If I have to venture a guess on the con rods breaking I would guess overrevving. Those engines were torquey but didn't like high revs.
    Hi bud

    There was always an engine knock for quite a while before the rod snapped. Eventually the vw dealers ran out of subs and offered the 2.0 golf engine conversion as a std option. I kept a broken rod on my coffee table for years as a souvenir. Happy days.

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  5. #24
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    Default Re: Questionable engine designs

    Quote Originally Posted by Darron View Post
    Hi bud

    There was always an engine knock for quite a while before the rod snapped. Eventually the vw dealers ran out of subs and offered the 2.0 golf engine conversion as a std option. I kept a broken rod on my coffee table for years as a souvenir. Happy days.
    So that sounds more like a big end bearing problem then which led to broken con rods.
    There is never a right time to do the wrong thing and never a wrong time to do the right thing!

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  7. #25
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    Default Re: Questionable engine designs

    Quote Originally Posted by MarcR View Post
    That is the question here... what weight does the opinion of the guy doing the dismantling hold?



    Not at all conclusive, but a cursory search for "ford 3.5l ecoboost engine problems" does not lead to the waterpump being an issue.

    Could it not be that the benefits of not having any pipes and integrating the water pump into the lump the way it has been done is actually the "best" design overall?

    I can see the frustration involved if that is a problem the owner or mechanic are facing, but it does not seem to be an issue in the grand scheme of things.
    This^^^

    They did a DFMEA identified that the coolant leak could be an issue and then added a weep hole. Sounds like the boys did their homework.

    Subjecting a diesel engine designed to a price point to the same level of scrutiny as nuclear system is daft.

    At the end of the day your job as a design engineer is to meet the companies design spec and ensure you donít kill anyone or f-up the environment on the way. Whether some component is difficult to replace or not by someone outside the companyís scope of operations is going to be well well well down the list of objectives.

  8. #26
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    Default Re: Questionable engine designs

    Quote Originally Posted by Oppies3800 View Post
    Lexus V8 and starter...
    Thatís easy, try a water pump on a Ford 6.7 Powerstroke in a F-750

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  9. #27
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    Default Re: Questionable engine designs

    With all the plastic in engines, the irony is that they are more reliable than ever, making more power with less fuel.

    What they are not anymore is being buildt to last 20/30 (and even more)years.

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  11. #28
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    Default Re: Questionable engine designs

    Quote Originally Posted by Mapog View Post
    With all the plastic in engines, the irony is that they are more reliable than ever, making more power with less fuel.

    What they are not anymore is being buildt to last 20/30 (and even more)years.
    I do agree but many of the older engines also came with factory flaws. Many little mods needed to be done on some to solve simple issues like overheating and oil starvation. We have drilled steam holes and water ports on engines that were simply not catered for.

    The down side of plastics is that once an engine overheats you can chuck it away. Most of them end up with buckled and ruined plastic intakes. Even fire risks from a simple overheat.

    I am with Francois on this it has become a mission to work on most high tech engines other than services. Unfortunately once out of warranty and motor plan the owner is faced with ridiculous repair costs.

    Think the time has come where it is an extreme risk to drive a vehicle once out of warranty. If one plan to be long term owner you need to sit down and carefully look at vehicles that reach 300k km with little to none repairs needed.

  12. #29
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    Default Re: Questionable engine designs

    Quote Originally Posted by Francois Theron View Post
    ...Yesterday I watched a video of the Ford 3.5 V6 Eco twin turbo engine being stripped. A very nice engine from a technical point except for one monumental slip up. The waterpump sits inside the timing cover! And although it does have a weep hole to the outside, according to the guy doing the dismantling, the majority of failures on these engines in the US are due to the waterpump leaking and water running straight into the sump.
    The Renault (Dacia, Nissan, Merc, Volvo) 1.5 dCi has a water pump inside the timing chain cover. It is used as a cambelt / timing belt guide. The pump is often included in many kits. Due to failures, it is recommended to change it anyway. Mine, upon removal, did not spin freely. So, I replaced mine.

    Renault insists on using what I call one-time clips instead of screw or V-band clamps. Once removed, they often cannot be reused.

    Many body panels use plastic push clips to hold them against the metal frame. I must have replaced over 20 of these one-time clips in my vehicle.

    The whole concept of exhaust gas recirculation (EGR) needs to be chucked out. After about six months, exhaust soot clogs the EGR valve requiring a messy cleaning job. Intake water injection can achieve the desired results of EGR in lowering chamber temp to reduce NOx production rather than using a heavy piped EGR.
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  13. #30
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    Default Re: Questionable engine designs

    Quote Originally Posted by Mapog View Post
    With all the plastic in engines, the irony is that they are more reliable than ever, making more power with less fuel.

    What they are not anymore is being build to last 20/30 (and even more)years.
    The thing is, modern engines actually do last for a long time if well maintained. I cannot remember when last I have heard of a modern engine needing an overhaul because of wear while well maintained. Most of the failures on modern engines are due to some ( mostly trivial) ancillary equipment failing. Such as a plastic coupling cracking and leaking water, or a flap valve breaking and jamming a piston, or EGR system clogging intake and pieces of carbon jamming valves etc. A high number of modern engine failures can be attributed to emissions control systems.

    From my experience the European and American engines are the worst in this regard.

    If your vehicle is maintained by a reputable establishment, they will pick up experience over time and replace problematic parts in time to prevent catastrophic failures from seemingly "cheap" parts causing expensive rebuilds or replacements.

    As per example, Toyota V6 intake manifold flap valves and BMW expansion tanks.
    There is never a right time to do the wrong thing and never a wrong time to do the right thing!

  14. #31
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    Default Re: Questionable engine designs

    Wens ek kan die ou kry wat die diesel filters op trekkers direk bokant die starter plaas

    Ek het nog altyd gevoel dat voordat 'n projek afgeteken word moet die ontwerper dit eers self diens en komponente vervang
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  15. #32
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    Default Re: Questionable engine designs

    Looks like 10 years is already a long time, there are many examples of plastics failing on Audi and VW engines, even the very popular Amarok V6 tappet covers need replacing at !!!! dollars, the 1.4 TSi VW engines with plastic water pump housings that crack to name a few.


    Quote Originally Posted by Mapog View Post
    With all the plastic in engines, the irony is that they are more reliable than ever, making more power with less fuel.

    What they are not anymore is being buildt to last 20/30 (and even more)years.
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  16. #33
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    Default Re: Questionable engine designs

    Quote Originally Posted by ArthurB View Post
    Looks like 10 years is already a long time, there are many examples of plastics failing on Audi and VW engines, even the very popular Amarok V6 tappet covers need replacing at !!!! dollars, the 1.4 TSi VW engines with plastic water pump housings that crack to name a few.
    Guess I am Lucky. My 305k km and 8 year old Amarok has had no plastic failures op to date, including the plastic tappet cover. Did replace a rubber turbo boost pipe recently though. Also 2 Polo`s under my roof and 3 others I service, with the eldest also 8 years, no plastic failures yet. Always knew I was a lucky guy.

    Groetnis

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  17. #34
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    Default Re: Questionable engine designs

    Quote Originally Posted by Mapog View Post
    With all the plastic in engines, the irony is that they are more reliable than ever, making more power with less fuel.

    What they are not anymore is being buildt to last 20/30 (and even more)years.
    Although we'll only really know the answer to that one in 20/30 years.

    In the meantime, manufacturers are giving longer and longer mechanical warranties.
    '97 Disco Tdi

  18. #35
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    Default Re: Questionable engine designs

    I read an interesting article a while back on a Mercedes Benz W124 series. The topic was less about the W124 series and more about answering the question about reliability vs durability.

    You can google it if you want; but in essence the author stated that while the W124 series wasn't seen as a particularly reliable vehicle in the sense that things did in fact go wrong (electrics, ancillaries etc), it was very durable. Durable in the sense that the main components like the chassis, suspension, gearbox, engine were sound and if it did eventually break a repair is economical and the car would just keep going for another 10yrs...durable. Similar to old Landies for instance; reliable nope, but keep working on them and they'll just keep on going.

    Generalizing now, but these days the balance between reliable vs durable is definitely skewed towards reliability. New vehicles are reliable which is great, but not designed to be durable enough to last 20 - 30yrs and you can see that in the design (planned obsolescence).

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    Default Re: Questionable engine designs

    Quote Originally Posted by Francois Theron View Post
    I don't think the original idea was planned obsolescence, but more a cost exercise in terms of manufacturing cost. I can understand this to an extent, as long as these parts are treated as wearing/degrading items to be replaced after a certain period.

    What I don't understand is where at times the failure of some of these parts, costing a few cents at times, can lead to instant and complete engine failure.

    As an example. I used to own a Land Cruiser 4.5 EFI, widely acknowledged as one of the most reliable engines ever made. One day, during a particularly hot spell and me with a heavy load and towing a trailer, noticed a sudden spike in engine temps. I stopped and found a small little rubber hose, about 50mm long, connecting the heater pipe to the cylinder head,
    And difficult to reach or see and even more difficult to change.

  20. #37
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    Default Re: Questionable engine designs

    What surprises me still is that modern engines have hundreds of sensors, ECU's, kilometers of cables etc, and sophisticated programs and then the most basic rubbishy gauges that hardly move when water is lost or oil does not flow properly etc. Almost as if the designers see drivers as nincompoops.

    Yet one reads over and over again that a hose burst and no alarm went off at all, the engine frekked and the owner and or manufacturer had to fork out a fortune to fix. And left someone stranded etc etc.

    Have never seen a stock EGT gauge in a car for example. We have driven BMW, Toyota, Audi, Renault and Peugeot over the ages and have had a good few problems with plastic and coolant loss, and friends with LR products with oil circulation, to name but a few.

    A few competant gauges measuring water temperature and level, EGT and such, with audible alarms, coupled with the rest of the tech, but also for the operator, would save so much trouble. A breakdown in Africa is horrid due to distance and safety. Many folk also do not understand the need for maintenance and safety checks as well.

    Tyre TPMS and cursed runflats another subject matter as well. The BM tyre warning is shite and has cost us a fortune, and left us stranded more than once.

    Just saying

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  22. #38
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    Default Re: Questionable engine designs

    Quote Originally Posted by Pieter de Waal View Post
    And difficult to reach or see and even more difficult to change.
    Now imagine doing that on the side of the road on a hot engine!
    There is never a right time to do the wrong thing and never a wrong time to do the right thing!

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    Default Re: Questionable engine designs

    Quote Originally Posted by Francois Theron View Post
    Now imagine doing that on the side of the road on a hot engine!
    Eina The 2.2 Ford and Mazda petrol engines had that engineering copied.
    Even worst were the hearer outlet between the firewall and engine. Had to remove an engine to fix that on a 2 2 Mazda

  24. #40
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    Default Re: Questionable engine designs

    Quote Originally Posted by ed rouillard View Post
    What surprises me still is that modern engines have hundreds of sensors, ECU's, kilometers of cables etc, and sophisticated programs and then the most basic rubbishy gauges that hardly move when water is lost or oil does not flow properly etc. Almost as if the designers see drivers as nincompoops.

    Yet one reads over and over again that a hose burst and no alarm went off at all, the engine frekked and the owner and or manufacturer had to fork out a fortune to fix. And left someone stranded etc etc.

    Have never seen a stock EGT gauge in a car for example. We have driven BMW, Toyota, Audi, Renault and Peugeot over the ages and have had a good few problems with plastic and coolant loss, and friends with LR products with oil circulation, to name but a few.

    A few competant gauges measuring water temperature and level, EGT and such, with audible alarms, coupled with the rest of the tech, but also for the operator, would save so much trouble. A breakdown in Africa is horrid due to distance and safety. Many folk also do not understand the need for maintenance and safety checks as well.

    Tyre TPMS and cursed runflats another subject matter as well. The BM tyre warning is shite and has cost us a fortune, and left us stranded more than once.

    Just saying
    Just because its not displayed on the dash does not mean there isn't a sensor for it. For instance my Audi monitors both EGT and turbo impeller speeds, its not displayed on the dash but if those values move out of preset parameter the car will go into limp mode to protect against further damage. Recently had an issue where my audit would go into limp mode, quick check of the faults showed there was a difference between requested and delivered boost even though the car still had plenty of grunt - turned out to be a split in a boost pipe. In a old school car I would have carried on driving not noticing the slight drop in performance in normal driving until that pipe burst leaving me stranded.

    Having an EGT gauge on a dash where 99% of drivers dont even know where the temp gauge is, is pointless. I realise most readers here are not in that 99%, but BMW, Toyota, audi etc etc are not building cars for us they are built for the masses. TPMS on the audi has saved me quite a few times, but critically the system does not rely on old school sensors in the rims - it monitors individual tyre rotation speeds so can pick up when a tyre goes flat.

    Often when you hear about these "sudden" roadside failures and get the full story there was a sequence of events warning the driver of impending doom - usually a loss of power but the driver carried on.

    Manufacturers are not forcing the market to buy more complex cars, the market demands it. Despite this massive increase in complexity modern cars are fundamentally more reliable than older cars. Yes sometimes a simple dud sensor can bring a working car to a halt, but on the flip side with the right tools you can zero in on the fault very quickly.
    Anton Muller
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