Not sure that’s true.
Detroit seemed to have lost sight of making a quality car starting in the Mid-70’s. Many many cars of the 60’s and early 70’s that came out of Detroit have HUNDREDS OF THOUSANDS of miles on them. A properly maintained small-block Chevy engine from the 60’s could easily go 250k+ miles. Same with Fords 289…or Chryco’s Slant 6 or their 318. I know a guy who still owns a Fury with the 318…Well over 500k miles…ORIGINAL engine…never torn into.
A well designed, well manufactured, well maintained 4-banger designed for longevity rather than maximum power output will reliably last hundreds of thousands of miles without regard to the RPMs it’s turning at 70 mph. A poorly designed, poorly manufactured, poorly maintained, or “designed for a pocket-rocket” engine of the same size will not.
A well designed, well manufactured, well maintained V6 or V8 designed for longevity rather than maximum power output will reliably last hundreds of thousands of miles without regard to the RPMs it’s turning at 70 mph. A poorly designed, poorly manufactured, poorly maintained, or “designed for a 4-second 0-60 time” engine of the same size will not.
Ther are virtually indestructable 4-bangers (the 22RE for one), and 4-bangers prone to problems. There are virtually indestructable V6’s and V8’s, and others prone to problems.
There are far too many variables for a “rule of thumb” based on number of cylinders alone.
Mountainbike, for those of us who don’t understand the differences between an engine that is designed for longevity and an engine that is designed for maximum power output, will you please explain the differences?
What comes to mind are valve timing settings and the shape of the lobes on the cam shaft, but other than that broad generic description, I am unable to explain the technical aspects and other differences I might be missing.
Max power output engines (racing engines) have much looser tolerences,mainly in main bearings but I would believe rod bearings also.
BMW made two 2.0 liter engines one a 4 banger and the other a in-line 6 (naturally). In every aspect the 6 was better,fuel milesge,oil control (as pistons get bigger oil control becomes more of a problem)the 6 was smooth easy pulling (like a turbine) with the four you were constantaly working that shifter. They also made a 2.3 16V 4 banger that put out over 190hp. This was probably 40hp more than that 2.0 6 cyl.
Yes, some engines are designed for maximum life and reliability. The legendary London Taxi has a virtually indestructable 4 cylinder Perkins engine. When in Asia I rode in Toyota Corolla diesel taxi,(4 cylinder) with over 1,400,000 km on it. The upholstery was ratty, but the engine ran just fine.
The above engines have durable bearings, rings, valves and valve seats, etc. Their output per liter is mormally not as much as pure performance engines. The Mercedes 1.8 liter diesel was the standard taxi engine in Germany from 1947 till the 90s.
Engines designed for performance have much higher compression pressures (via compression ratios, turbochargers, or even superchargers), hotter and bigger explosions in the cylinders (due not only to the higher compression but also due to more fuel being pumped in…bigger injectors, longer pulsewidths, longer valve durations, bigger or more valves, less restriction in the intakes and exhausts, you get the idea), and even have the crankshafts loaded down more (superchargers, heavy duty alternators). These things create much higher stresses on the components as well as the lubricant (oil). These stresses take their toll.
Some of the added stresses are obvious, some less so. Comprssion rings are designed to sprad out and hug the cylinder walls with force from above. The more force, the tighter they push. That adds to wear.
Um, I should probably explain that “more valves” comment. Each cylinder is a circle. The more circles you put into the outer circle, the more area you fill. Performance engines today often have 4 valves to push as much fluid as possible, rather than the 3 valves in basic engine.
There are too many variables in engine designs to make that statement. All things being equal, yes, higher piston speed and more turns of the crank means more wear. But different engines use different metallurgy, materials, bearing loading, bore and stroke ratios, cooling efficiency, all kinds of things can affect engine life.
Although I know very little about mechanics, I suppose a lot would depend on the design and history of the two engines being compared. Some four-cylinder engines must be better designed than some sixes. Am I right or wrong?
Other things being equal, which they never are, I suppose the six-cylinder engine should have a longer lifespan.
nonsense. a V6 is a four-cycle engine.
A 4-banger is a slang term for a four cylinder, not a four cycle. Since only one of any four-cycle engine’s cycles is a “bang”, no matter how many cylinders it has,4-banger wouldn’t make much sense as slang for a four-cycle engine.
All gasoline automotive engines are four-cycle. Slang for that is a “suck-squeeze-bang-blow” engine. Diesels are also four-cycle engines, although they self-ignite when the fuel is sprayed in at the top of the compression stroke rather than create the combustion with a spark.
The four cycles consist of the intake stroke, the compression stroke, the power stroke, and the exhaust stroke.
Who said anything about four-cycle engines? Is your dyslexia acting up, denverdog? I hate it when it happens to me.
Yours is an interesting and scientifically valid comment. In any experiment, the purest way to determine cause and effect is to control 100% of the variables and change only one, then rerun the analysis. The problem here is that as soon as you go from an inline 4 to a V6 you change countless variables.
Theoretically, if all characteristics of the engines were the same, including valve parameters (impossible because you’ve increased the number of valves by 50% and on an overhead cam engine doubled the camshafts…you’ve also changed the timing belt configuration), ignition systems, materials, cylinder sizes and geometries (which would make the V6 50% larger total displacement…see how impossible it is to keep the other variables the same?) temperatire profiles per cylinder, and the other thousand things, then yes, the V6 should last longer simply because it has more pulses per crank rotation and operates smoother…but at this point you’ve already changed the displacement by 50% and numerous other important variables, voiding the results.
It’s impossible to keep everything the same but the number of cylinders. Thus, the question becomes only a thought experiment, impossible in the real world.
Denverdog’s comment on my post only makes sense if one assumes that “4-banger” means “four-cycle”. If that were true, then he’d be right, my post would be “nonsense”.
Perhaps I should lay off the slang for awhile…
Yeah a 4 banger will last just as long if you drive them 10k a year 0r 50k.
exactly, high RPMs are hard on an engine.
Well, I have been arguing for the V6 on here but honestly I don’t have a V6, I drive a V8. However, I run it a quart low on oil, 1/2 gallon low on coolant, drive with the brakes on for a while, to warm it up faster. Then I never use 4th gear because the extra RPMs is good for the engine. On the highway I drive around 80 MPH, that keeps the engine running over 4 grand. It is a little hard on gas mileage, but for the extra miles I get on the engine, and the extra power I have, I figure it is worth the extra fuel. I never keep one over 300k so I don’t know how many miles I could get on the engine. In '06 when I left Carquest, they had a Chevy van V6 with 375K miles on it and still drove it a while after that, however, they didn’t drive it as hard as I do. Well, you old Pros, keep up the good work!!
Your “extra rpm is good on the engine” idea is hilarious,where did you ever get that idea?
I got the idea from some of the posts on here. Several say that high RPMs are good for an engine, especially a 4 cylinder.
pleasedodgevan2 said so in the 5th post on here
Who said that high RPMs are good for an engine?
When I read this thread, all I can find is lots of people saying there are many, much more important factors that affect engine longevity. I also see people saying that what constitutes “high RPMs” varies according to engine design. What is high for one engine with loose tolerances, high compression, and two valves per cylinder might be normal for another engine with tight tolerances, low compression, and four valves per cylinder. By focusing only on RPMs, you show the limit of your imagination and ability to understand foreign concepts.
Why do you keep replying to Whitey’s posts? He has made it clear he doesn’t want to rehash this discussion with you again, yet you keep replying to his posts. Am I the only one who sees that as disrespectful?
Yep and who cares??