Do modern engines last longer?

Hi folks,
This question came into my head a few days ago. I often hear people suggesting that the latest vehicle engines last longer and are more
trouble-free than older engines. But I also hear people saying, just as often, "They don't make them like they used to".
I was looking at a Dennis Z Type lawnmower a few days ago. I am hoping to acquire one. For those who don't know, this is a legendary machine. I think its engine is probably the best lawnmower engine ever made. It has forced lubrication and an oil filter, complete with a passage for oil through the crankshaft, and was introduced in 1922.
Now it's possible that one might look back at older products and view them as being superior because all the poor quality products from the era wore out and were replaced. It's also likely that the answer to the question will depend on the type of engine you look at, and the quality of construction. But I'll leave it as a general question, as I'm interested to hear anyone's experience.
I get the impression that perhaps engine technology is moving in two opposing directions. On the one hand, improving technology such as better lubricants, filtration and bearing materials, are resulting in components lasting longer. But on the other hand, the whole industry appears to be moving towards less maintainable engines. Engines which are wholly dependent on electronics, sometimes with coated rather than lined cylinders. Engines which are difficult for anyone to maintain at home. Perhaps this is why I don't hear people talk about replacing piston rings, or having crankshafts regound anymore? Or perhaps these parts last for the lifetime of the vehicle?
I'd be interested to hear people's opinions. I'd also be very interested to see data comparing wear rates in modern and old engines, if anyone knows where I can find such data.
Best wishes,
Chris Tidy
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wrote:

I tend to agree with you to some degree, however, as consumers our expectations have gone up over the years. It wasn't that long ago that cars were worn out at 20K miles, and that automobiles came with instructions that told you how to repair the babbit bearings in the engines yourself. Now, a car with 200K miles is normal, even barely broken in. Machines made by craftsman who understood the fine details of quality machinery were rare and highly sought after, as they had under one hat engineering, design, assembly, and maintenance skills, but they couldn't make them very fast or very cheap. Now these skills are most commonly segregated to individuals, with less and less having all those abilities at one time. Competition has ensured that quality and endurance are important, as well as cost. Modern automotive engines are designed and can be easily reproduced with tolerances unattainable not that long ago, and the tight tolerances, combined with carefully worked out assembly processes ensure that the cost comes down with little to no loss in quality. During the Civil War, every citizen soldier had his own musket, each of a slightly different caliber, so they had to cast their own bullets, and repairing them was difficult due to lack of interchangeability. Mass manufacturing methods not that long afterwards resulted in rifles being crafted in great numbers with precision, which drove the cost down and the deadliness of warfare up.
That said, all engineering design is a compromise. Quite often a lower quality part is selected for a car or other machinery because it keeps the cost down. Rarely do we notice these things, and when we do, it's often a big deal. If money is not object, someone somewhere will build you the machine you want with the very best components that you want, but it will cost a lot of money, be hard to find parts for, and only used by limited numbers of people. We as consumers also have to make a compromise based on our needs, wants, and wallet, and while I'd like to have a Bugatti in the driveway, I don't have the money or a practical need for it. I just need a car I can rack up the miles on with low maintenance (as compared to my Triumphs...) and do everything else I need it to do.
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Bernie wrote: "During the Civil War, every citizen soldier had his own musket, each of a slightly different caliber, so they had to cast their own bullets, and repairing them was difficult due to lack of interchangeability. Mass manufacturing methods not that long afterwards resulted in rifles being crafted in great numbers with precision, which drove the cost down and the deadliness of warfare up."
Buncha crap, Bernie. Muskets and ammunition were mass produced during the civil war period. I read your post with some interest until I got to that part. It totally denigrated anything else you had to say. The "one bad apple in the barrel thing", don't you know.
Bob Swinney
wrote:

I tend to agree with you to some degree, however, as consumers our expectations have gone up over the years. It wasn't that long ago that cars were worn out at 20K miles, and that automobiles came with instructions that told you how to repair the babbit bearings in the engines yourself. Now, a car with 200K miles is normal, even barely broken in. Machines made by craftsman who understood the fine details of quality machinery were rare and highly sought after, as they had under one hat engineering, design, assembly, and maintenance skills, but they couldn't make them very fast or very cheap. Now these skills are most commonly segregated to individuals, with less and less having all those abilities at one time. Competition has ensured that quality and endurance are important, as well as cost. Modern automotive engines are designed and can be easily reproduced with tolerances unattainable not that long ago, and the tight tolerances, combined with carefully worked out assembly processes ensure that the cost comes down with little to no loss in quality. That said, all engineering design is a compromise. Quite often a lower quality part is selected for a car or other machinery because it keeps the cost down. Rarely do we notice these things, and when we do, it's often a big deal. If money is not object, someone somewhere will build you the machine you want with the very best components that you want, but it will cost a lot of money, be hard to find parts for, and only used by limited numbers of people. We as consumers also have to make a compromise based on our needs, wants, and wallet, and while I'd like to have a Bugatti in the driveway, I don't have the money or a practical need for it. I just need a car I can rack up the miles on with low maintenance (as compared to my Triumphs...) and do everything else I need it to do.
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Sorry. My retort should have been directed to carl m, or whoever the pseudonym was. My newsreader must have appended the wrong name. Apologies to Bernie.
wrote:

I tend to agree with you to some degree, however, as consumers our expectations have gone up over the years. It wasn't that long ago that cars were worn out at 20K miles, and that automobiles came with instructions that told you how to repair the babbit bearings in the engines yourself. Now, a car with 200K miles is normal, even barely broken in. Machines made by craftsman who understood the fine details of quality machinery were rare and highly sought after, as they had under one hat engineering, design, assembly, and maintenance skills, but they couldn't make them very fast or very cheap. Now these skills are most commonly segregated to individuals, with less and less having all those abilities at one time. Competition has ensured that quality and endurance are important, as well as cost. Modern automotive engines are designed and can be easily reproduced with tolerances unattainable not that long ago, and the tight tolerances, combined with carefully worked out assembly processes ensure that the cost comes down with little to no loss in quality. That said, all engineering design is a compromise. Quite often a lower quality part is selected for a car or other machinery because it keeps the cost down. Rarely do we notice these things, and when we do, it's often a big deal. If money is not object, someone somewhere will build you the machine you want with the very best components that you want, but it will cost a lot of money, be hard to find parts for, and only used by limited numbers of people. We as consumers also have to make a compromise based on our needs, wants, and wallet, and while I'd like to have a Bugatti in the driveway, I don't have the money or a practical need for it. I just need a car I can rack up the miles on with low maintenance (as compared to my Triumphs...) and do everything else I need it to do.
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My bad. I was a bit distracted and forgot to check my facts. I had the wrong war in mind. Haven't had an opportunity to spend much time absorbing details of history like that in a really long time, so I'm really rusty.
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"Gunner Asch" wrote: Eli Whitney was the father of "weapons interchangability" ^^^^^^^^^^^^^^^^^ Yeah. He invented the cotton gun.
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On Sat, 02 Aug 2008 21:26:31 GMT, "Leo Lichtman"

Actually he also invented interchangeable parts. See http://www.eliwhitney.org/inventor.htm for details.
"It was Whitney's idea to make all the parts of his rifles so nearly identical that the machines parts could be interchangeable from one gun to another. "
Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom)
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I missed the Staff meeting, but the Memos showed that "Leo Lichtman"
in rec.crafts.metalworking :

    LOL. Is that anything like the Potato Gin?
    Whitney's attempts at mass production were funded by the US Congress. Naturally, he went way over budget, and way over schedule, and did not quite deliver what he had proposed. But he did get much of the basic work done.
tschus pyotr
-- pyotr filipivich "I had just been through hell and must have looked like death warmed over walking into the saloon, because when I asked the bartender whether they served zombies he said, Sure, what'll you have?'" from I Hear America Swinging by Peter DeVries
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On Sat, 02 Aug 2008 13:48:38 -0700, with neither quill nor qualm,

I received copies of a dozen headlines in an email this morning. None of us can figure out how these buffoons graduated high school and/or college. Here's the text of a few relating to this thread offshoot:
1) Volunteers Search for Old Civil War Planes
2) Federal Agents Raid Gun Shop, Find Weapons

One Atta Boy going his way! Do what you feel in your heart to be right - for you'll be criticized anyway. You'll be damned if you do, and damned if you don't. -- Eleanor Roosevelt
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Here's the mother: (you gotta see this)

http://www.youtube.com/watch?v
VQYj_zk_M
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wrote:

In the US maybe, but he was 20 years behind, gasp, the french (Blanc) and whitney never actually actually implemented or even designed a manufacturing process capable of producing his guns with interchangeable parts. He did show the need and did the congressional display entirely with hand made parts.
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short answer, "yes", at least for automotive use. I have 1936, 1938, 1951, 1959, 1985, 1986, 1993, 1997, and 2001 vehicles under my purview. up through the 51 year car, 150K miles or so was the limit - at that point the bores were 40 to 60 over, rings shot, no compression, crank oval, no oil pressure, etc. 59 is good for 200K easy. there was a major change in the metalurgy of the engine block, etc, as I understand it - we can debate what changed, but the longevity is just not an issue
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In additions to metallurgical advances, there have also been major, good changes in lubricating oil and manufacturing precision.
I was talking to a friend who runs an engine rebuilding business, specializing in rebuilding antique and classic engines. I told him I was looking for plastigauge in a parts store, but they didn't even know what it was.
He said he does not check clearances on new bearings when using new cranks, or even when he has turned a crank himself and measures journals. He says bearings, and new cranks, are the nominal size the mfg says they are, to a perfectly adequate precision, not like years ago. He says measurement capability and machining operations are much improved today.
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Don Stauffer in Minnesota wrote:

Sure. Today they are made under computer control, instead of union workers.
--
http://improve-usenet.org/index.html

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Your friend is an idiot. He risks a destroyed engine and labor to redo it to some parts store flunky that hands him the wrong bearings; perhaps a returned box that lists correct size, but has bearings someone extchanged in the box. Perhaps a machine shop apprentice who sneezed when punching in the finished OD into the CNC crank grinder. Anything with the Human factor contributing is guarenteed to fuck you up at some point. And don't think machine made and packaged bearings can't be defective. I once got a set of rod bearings that had skipped the punch step that puts the anti spin tang on the end of the shell. Just guess what would have happened if I had installed them. JR Dweller in te cellar
On Sat, 2 Aug 2008 08:24:37 -0700 (PDT), Don Stauffer in Minnesota

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Trust but verify. All it takes is a bit of crud under the bearing shell to ruin your day.
Wes
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Don Stauffer in Minnesota wrote:

I can see that improved precision will result in a longer service life, provided that the surface finish is excellent. It's my understanding that for a hydrodynamic bearing in which the bearing's length, radius, rotational speed (for this, take the engine's idling speed) and lubricant viscosity are fixed, the maximum allowable load is inversely proportional to the radial clearance. So if the parts are very close-fitting, they will likely be able to carry a greater load than necessary when new, but the load they can carry without surface-to-surface contact will fall as the clearance increases due to wear.
Provided that the surfaces are not touching (except when starting and stopping), the wear rate will probably be at a minimum soon after the bearing surfaces are new, and after that it will slowly rise. If you are able to manufacture bearing surfaces with excellent precision and an excellent surface finish, you prolong the period in which the bearing is able to carry a greater load than is necessary, and prolong the period in which the rate of wear is low. Eventually, the bearing will no longer be able to support the load without the surfaces touching, and the wear rate will rise dramatically.
Babbitt metal can probably be seen as a bearing material which develops an excellent surface finish during the running-in period.
I imagine that multigrade oils reduce the wear rate at high temperatures and increase engine efficiency at low temperatures. I am not certain about the effect of oil additives. Do they work by adding a layer of slippery graphite to the bearing surfaces, in the way that cast iron does? Perhaps someone can explain?
Best wishes,
Chris
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William Noble wrote:

Thanks for sharing your experience, William. If any designers out there know of significant changes in car engine block metallurgy over the last 50 years or so, and are able to share them, I would be very interested to hear.
I'm under the impression that cast iron blocks and/or cast iron cylinder liners were the norm in the 1950s, and that cast iron liners still are today, but I could be wrong. There have been some engines which use coated aluminium cylinders, but after the Nikasil and sulphur problems in the 1990s, I thought they were in decline.
Best wishes,
Chris
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Christopher Tidy wrote:

Cast iron blocks have been around since day one of engine production. However the iron alloys used today are FAR superior. It allows thinner castings that have tighter grain patterns and through the use of newer alloys the wear and machining characteristics are such that the blocks made today last longer.
99% of the aluminum blocks use steel liners cast into the blocks. The rest use a type of chrome plating of the cylinder walls. Most of them are not built for long life though. Many are air cooled small engines. Things like lawn mowers and weed eaters. The industrial/heavy duty ones have iron or steel liners.
--
Steve W.
Near Cooperstown, New York
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Steve W. wrote:

It's interesting that such progress can be made while the material keeps the same name. But I guess it's just like vehicle tyres. People still call them "rubber", but they wear a lot better today.

Do you mean steel, or cast iron? I don't think I've heard of an engine using steel liners. I believe the extra carbon in cast iron leads to a graphite film on the surface which gives the material better bearing properties.
Best wishes,
Chris
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