Has 300,000 miles become the new normal for cars. How are more and more these little 4 cylinder engines able to do it? (trucks, purchase)
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There is no solid evidence that running a gasoline engine at low RPM extends the life of the engine.
Good point but I am looking for just that. (Solid Evidence) For now this diesel example from the way back machine will serve my purpose. It is also a matter of physics. Low RPM equals less friction less stress on components. Not to worry I will find (Solid Evidence).
Location: We_tside PNW (Columbia Gorge) / CO / SA TX / Thailand
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well... low RPM will mean FAR less combustion cycles in 300,000 miles. (Gas or Diesel)
Gas (ick) does not have to lubricity or energy content of diesel, so ... it may never exceed life of a diesel, but with proper maint and lubrication can likely equal / at least last 300k (and many do). My Diesel injection mechanic has over 700k miles on his S-10 gas pickup... (A very robust and proven GM engine design).
Consider all the 'beater's running around Africa and South America who just keep chugging along in very challenging heat and service requirements (dirt roads). Manual trannies, and lots of MUD (stress). Many were imported 'worn-out' from developed countries.
Gas vs diesel... Not so easy to brew your own gas. Very easy to brew your own diesel, or to use many alternative / replacement fuels that burn just fine in any Diesel ICE.
BTW... I run at 1700 RPM @ 60mph in my TDI Diesel cars (Sweet spot)
Trucks... 1200 RPM @60 (cummins) CAT likes to turn much slower.
Ironically... my IDI diesels like to run FLAT out 3500 - 4000 RPM for best economy. They operate best at high temps and high RPM (no turbo). They can run to 500k without a $500 rebuild. Turbo IDI's I seem to get 350k to 400k, and they are 'tired' but still OK. (extra heat / stress of turbo wears Head / Valve / Combustion components)
Thanks for the explanation. The only thing I would like to add to that is
Quote:
Originally Posted by StealthRabbit
well... low RPM will mean FAR less combustion cycles in 300,000 miles. (Gas or Diesel)
Gas (ick) does not have to lubricity or energy content of diesel, so ... it may never exceed life of a diesel, but with proper maint and lubrication can likely equal / at least last 300k (and many do). My Diesel injection mechanic has over 700k miles on his S-10 gas pickup... (A very robust and proven GM engine design).
Consider all the 'beater's running around Africa and South America who just keep chugging along in very challenging heat and service requirements (dirt roads). Manual trannies, and lots of MUD (stress). Many were imported 'worn-out' from developed countries.
Gas vs diesel... Not so easy to brew your own gas. Very easy to brew your own diesel, or to use many alternative / replacement fuels that burn just fine in any Diesel ICE.
BTW... I run at 1700 RPM @ 60mph in my TDI Diesel cars (Sweet spot)
Trucks... 1200 RPM @60 (cummins) CAT likes to turn much slower.
Ironically... my IDI diesels like to run FLAT out 3500 - 4000 RPM for best economy. They operate best at high temps and high RPM (no turbo). They can run to 500k without a $500 rebuild. Turbo IDI's I seem to get 350k to 400k, and they are 'tired' but still OK. (extra heat / stress of turbo wears Head / Valve / Combustion components)
“Drive a diesel at altitude and you’ll see other cars struggling while you zip past,” Ciatti said. “The effect is very noticeable.”
Once you get hooked on Low RPM Torque... tough to go back.
I got hooked early (at birth... parents were truck-drivers), then I raced Thumper MC's... (still do).
Thanks for the explanation and your experience. The only thing I would like to add to that is the recommended first over haul of many diesels is 800,000 to over a million miles.
"The Volkswagen 3.6l VR6 FSI engine is very reliable and durable engine and it easily reaches 250,000 miles (400,000 km) mileage and more. It is required high-quality fuel and oil with regular oil change and proper maintenance. There are not many common problems found in consumer's reports about this engine. We can only single out some problems with ignition coils in first years of production. Also, the engines with big mileage can have oil leaks from crankshaft oil seals."
"Toyota conducted a recall campaign for cars with 2GR-FE and 2GR-FSE produced until 2010. The reason for that became a problem with an oil leak from the rubber hose which feeds the VVT-i lubrication system. The manufacturer replaced that rubber part by a metal pipe.
If the 2GR engine has a damaged cylinder wall surface, the entire cylinder block has to be replaced. The thin walls of the cylinder liners make the engine impossible to bore the block. The liners itself are cast into the aluminum engine block.
The 2GR-FSE engine features the overheating of the fifth cylinder. That is caused by the design flaw. The problem leads to high oil consumption at first and scratches appearance on cylinder wall later. If you read above, now you know the expensive end of that story.
The all GR family has a common problem with unreliable water pump and ignition coils. In some cases, they don't last longer than 30-50k miles, and that is very annoying. The 2GR-FE has longevity about 200,000 miles (300,000 km). The 2GR-FSE and 2GR-FKS engines are more technologically advanced, powerful, and fuel efficient, but less reliable."
I do know for sure is that Toyota (and Honda) is required to use thinner-cylinder walls in order to reduce physical-size and curb-weight of engines for better MPG rating. After about 200,000 miles rated lifespan, according to motorreviewer.com, the engine may gradually start to develop "cracking" around block due to thin-walls, high-temperature wear, and fatigue tear after many years of use.
...Which automatically concludes (if engine block does crack) that Toyota engines do WORSE on long-term durability than Mazda and some American makes easily (including new 2020 Ford Fusion S) that build them heavier and stronger in first place, more suitable for 24/7 commercial-use (industrial) fleet drivers. More MPG = Less Durable.
That's what I'm trying to point out. Toyota has been less-friendly to 24/7 commercial-use fleet drivers than what our biased-media is trying to say that brainwashes you in error that Toyota is always gospel-truth. Yeah right...
I believe your cause and effect statement is a poor generalization and way too simplistic.
Pretty much any engine today will last 200-300k miles with proper maintenance. I believe these are the issues:
1. Engine has to run at the rpm range designed for the engine. I would not run any engine at 1250 rpms for an extended period of time since gasoline engines are not designed for that. My TDI doesn't even run at 1250 rpms (with DSG, it will downshift at 1400). I would not accelerate from that rpm without a downshift with a gas engine to get to speed. I have a Frontier with a 6 speed manual, I do not cruise below 1800 rpms and don't do any heavy acceleration below 2500 rpms. Conversely, I wouldn't run most engines (with a few exceptions) at 5-6000 rpms all the time.
2. Maintenance of the engine according to schedule, if not sooner. I use synthetic fluid in my newer cars. All filters replaced on time.
I had a BMW S38b35 engine that had 190,000 miles on it before I sold the car. I put 100,000 miles on the engine, including about 15,000 TRACK miles. That means regularly revving the engine from 4,000 to 6,500 rpms. NEVER had a problem with the engine. Why? Because I changed the synthetic oil regularly (including before every track session), and did compete maintenance every year, including valve adjustments. Cruised the engine at 3,000 rpms on the freeway, not lower. Because that was what the engine was designed to do.
Often times engines don't last because people neglect maintenance. You would be surprised how many owners do that. And I think in the quest for mpgs, the engines run at an RPM that is too low for the engine. I don't believe the small engines pulling 3500 lb+ cars should be running and accelerating at engine speeds below 2,000 rpms.
Last edited by Vic Romano; 02-14-2020 at 12:54 AM..
How did you manage to log 15,000 miles on track? You doing 24 hour endurance events? At an average of 100 MPH, this would take 150 hours, just short of a 24 hour week.
Not saying you didn't do it, just asking how you managed to.
Cruise RPM is going to depend on engine design, my old 4.6 Ford in the Cougar runs about 1250 RPM at 40-45 MPH, and it seems to be OK, really if you keep a light foot on the gas, it will go on down to about 1000 RPM in 3rd gear, this is about 25 MPH. This is the old Ford AOD transmission, an automatic, so the designers were "OK" with this RPM. No chugging, oil pressure is the same as at higher RPM, on the "r" of "norm" on the factory gauge. But how the cam is set up, and stroke length, are going to dictate what the minimum RPM an engine will run right at. I agree that you need more RPM for large throttle openings, than you do for small. The old Scirocco also runs quite smoothly at low RPM, in both cases FI helps with this, as you don't need much intake velocity to aid atomization. Particularly the old K-Jet injection on the Scirocco, these run about 70 PSI fuel pressure, and at low fuel flows make a very fine mist.
"The Volkswagen 3.6l VR6 FSI engine is very reliable and durable engine and it easily reaches 250,000 miles (400,000 km) mileage and more. It is required high-quality fuel and oil with regular oil change and proper maintenance. There are not many common problems found in consumer's reports about this engine. We can only single out some problems with ignition coils in first years of production. Also, the engines with big mileage can have oil leaks from crankshaft oil seals."
"Toyota conducted a recall campaign for cars with 2GR-FE and 2GR-FSE produced until 2010. The reason for that became a problem with an oil leak from the rubber hose which feeds the VVT-i lubrication system. The manufacturer replaced that rubber part by a metal pipe.
If the 2GR engine has a damaged cylinder wall surface, the entire cylinder block has to be replaced. The thin walls of the cylinder liners make the engine impossible to bore the block. The liners itself are cast into the aluminum engine block.
The 2GR-FSE engine features the overheating of the fifth cylinder. That is caused by the design flaw. The problem leads to high oil consumption at first and scratches appearance on cylinder wall later. If you read above, now you know the expensive end of that story.
The all GR family has a common problem with unreliable water pump and ignition coils. In some cases, they don't last longer than 30-50k miles, and that is very annoying. The 2GR-FE has longevity about 200,000 miles (300,000 km). The 2GR-FSE and 2GR-FKS engines are more technologically advanced, powerful, and fuel efficient, but less reliable."
I had that VR6 in my 2007 Touareg, which was rock solid.
If properly maintained most any vehicle can achieve this
Sadly, to many owners are Gas & Go so you won't find them
on this thread.
True.
A long time ago I heard someone remark that cars would last forever if they were maintained like airplanes. I liked my 90 GMC 4X4 short bed, so I tried it.
Still going well, 30 years and 400,000 miles.
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Thanks for the explanation. The only thing I would like to add to that is
Toyota has been less-friendly to 24/7 commercial-use fleet drivers than what our biased-media is trying to say that brainwashes you in error that Toyota is always gospel-truth. Yeah right...
