Engine life


#1

a v6 engine turns at 2000rpm at 70mph,a 4cyl turns at 2500-3000rpm,a 25-30% increase.after 100000 miles the 4cyl engines life will be less than a v6.a 4cyl also downshifts on small hills.a v6 should last longer,is this correct?


#2
  1. Too little info. Robustness of design counts for far more than cyl #.
  2. Steady-state crusing in top gear produces only a very minor portion of engine wear; it’s probably the easiest type of driving from the engine’s standpoint.
  3. Keeping on top of maintenance would make a big difference, esp things like the PCV valve.
  4. Most modern engines last long enough for one to get sick of the car anyways.

#3

Motors that turn more rpms are made to handle it, just like a motor with higher commpression will have bigger stronger head gasket.
Do upkeep and both will last a long long time.


#4

a v6 turning 2000rpm = 171,400,000rpms in 100000miles,a 4cyl at 2500rpm would turn 214,300,000rpms in 100000 miles,engine wear has to be more.a 4 is basically the same as a v6 , running at higher rpms is the difference.


#5

Then you also have to consider that the 4 Cylinder car will have less moving parts to wear.


#6

what less parts,cam,crankshaft,trans,only 2cylinders,the other 4cyl.go up and down 42900000 more times,thats not more wear?


#7

90% of engine wear happens at start-up. Engine wear has a lot more to do with maintenance and engine design than total number of RPMs. There was a thought at one time that a larger engine with power to spare would last longer than a smaller engine that had to strain more. But current designs see a lot of 4-cyl engines with impeccable reliability.

One reason I like 4 cylinders over V6’s is better fuel economy and less parts. Modern V6 engines typically have twice the camshafts and cylinder heads, 50% more cylinders, 50% more spark plugs, 50% more coils, 50% more injectors, and two banks of intake and exhaust. The space taken by a four cylinder is a lot less than V6’s, and are easier to work on. Spark plugs are typically a breeze to reach. Some V6’s require engines to be shifted or mechanics with double joints to reach.

The only advantage I look at for the V6 option is additional payload. A four cylinder is limited by the size of load it has to carry. A V6 can handle more.

For my daily commute, I prefer the four cylinder. Typically, there is only me and a co-worker, driving in rush hour traffic 80% of the time. The last one I had lasted 15 years and 325,000 miles. For the family truckster, I have a V6. Most of the lime, there are 5 or more of us and, depending on the activities, a load of gear or a small trailer.


#8

The simple answer is that there will be more cylinder/ring wear, but it doesn’t make any real difference. The 4 cylinder engine will likely last past 200K with proper maintenance


#9

my question is simple,will any engine that during its lifespan last the same as an engine that turns 20% slower.a chevy malibu with a 4 or a v6 is the same car.a ford fusion v6 or a 4cyl.300 lbs difference. any one have any references i can look up.


#10

Another case of a OP that comes for proof when what we offer here is opinion,the proof is yours to seek.


#11

In theory, you have a point, but only in theory. The differences between engines far exceed just the number of cylinders. No otherwise-identical 4, 6, and 8 cylinder engines exist. And experience says there is no practical difference between these engine in real life. No data that I’m aware of supports your idea.


#12

Whether the engine has four or six cylinders, engines that turn at a higher rate of RPMs are designed and built to do so. If all other things are equal, and if you take good care of both cars, they will both last just as long.

When four cylinder engines became popular in the fuel crisis of the 1970s, they tried to use both engines in the same car bodies. Today’s four cylinder cars are much lighter than they used to be, and as long as you don’t overload them, and as long as you take care of them, they will last as long as you want them to.

Since most engine wear happens at start-up, consider that a small four cylinder engine reaches its proper operating temperature faster than a larger six cylinder engine.

Lastly, a large four cylinder engine can turn slower than a smaller six cylinder engine, making cylinder count meaningless.


#13

No, I don’t have any references. Are you looking at a Malibu or Fusion? If so, rest assured that the 4 cylinder versions will be plenty reliable. Most people buy family sedans with the 4 cylinder engines.


#14

If you want references you can look up, try Google, Yahoo, etc. Let us know what you find.


#15

Most six cylinder engines have a V formation, while most four cylinder engines have an I formation. The V6 will have an extra cam shaft, a longer timing belt/chain, extra valves, an extra intake manifold, an extra exhaust manifold, two catalytic converters instead of one, etc.


#16

The higher the RPMs the less load on the engine. The higher engine speed helps a lot more than it hurts. The V-6 has to be allowed to run slower or it would eat all the fuel in the world.


#17

Agree; a 4cylinder engine is usually smaller and heats up faster, thereby incurring LESS WEAR. For normal US driving, a 4 cylinder engine will likely last longer than a V6, since the full power of the engine is seldom used.

A major oil company fleet manager in the North once described what their car and truck specs were. He told me they would order the SMALLEST standard engine, since large engines would take too long to warm up, the speeds were low and fuel was expensive. They had the fewest problems with small engines.

The only place where a V6 might last longer would be in Germany where very high speeds (100 mph) are legal and the engine gets a real workout.

It’s important to separate THEORY from REAL LIFE driving situations!


#18

“Since most engine wear happens at start-up, consider that a small four cylinder engine reaches its proper operating temperature faster than a larger six cylinder engine”.
I would sure like to know why a 4 will warm up faster than a 6 or 8. Is it because it has to work harder? And how many 4s do you know of that are larger than 6s? Why don’t they put 4s in Crown Vics or Mercury Marquis or Town Cars, or F-150s or Chevy Impalas or Silverados, or Dodge Rams?


#19

In theory the engine that spins less revolutions over the years should last longer. Yet, this is only one variable of many that determines how long an engine will last. Other variables are much more significant and have greater impact on longevity. The frequency of oil changes, number of short trips from cold starts vs lots of highway miles, etc. are all much more important than the difference in rpm in top gear.

If you could control all the other variables you’d likely get more life from the V6, but the other variables are too numerous and too significant to control. In the end there is no real world difference in the service life of a V6, V8, or 4 cylinder motor in the same car.


#20

The higher the RPMs on an engine, the greater the “thrust” load the rings and pistons put on the cylinder wall. (The “thrust” is the side force.) I remember studying this back in my internal combustion engines class.

But, as others have already noted, the other factors affecting engine wear are far greater than an extra 42,900,000 RPMs over 200K miles. The OP’s point is valid primarily in theory only.

I remember a study Ford did a few years back. They did two tests:

In the first test, the drove a car around a track continuously at 60 mph for 100,000 miles (stopping only to change the oil and change drivers). They never let the engine cool down. After 100,000 miles, the amount of cylinder wall wear was that of engine with less than 10K miles on it. Very little wear.

In the 2nd test, they forced the cooling system fluid to never warm up (ie: they kept cooling it off to act as though the engine was always ‘warming up’). They found the wear on the engine was quite accelerated, especially in the cylinder walls.