Technical Engines that like to be worked: fact or fiction

Growing up, I've heard different people say some engines like to be "worked"(not lugged), as in they like to pull a load rather than just cruise along. I've heard this typically of big blocks. These people claim the engines won't last long if they have an easy life. Have any of you heard this and can confirm or deny the story first hand? I suspect the only way one would know would be to have the same engine run in 2 different vehicles with one an easy life and the other working and compare the life span of them.

 

Pretend your body is an engine...then fast forward 40 years.

What would run/feel better?

 

I've found (in my almost 70 yrs.) that MOST engines like to be "run".
I cringe when I see people wanting to put 2.90 or 3/20 rear end gears in their cars, when in actuality, most cams, even OEM cams, like to turn some RPM. "I don't like the noise". Then get a Lincoln..!
Sure, there are some luxury cars/engines that need to be quiet while running down the road. The cams, intake manifolds, cylinder heads...everything from the pistons up...are designed... to be run at lower rpms.
Like motorhome engines. They are a bit of a combination. They should be sorta quiet, but, they need low/midrange speed horsepower to pull all of that weight. Not high rpm power to wear out quickly, they need to go 300,000 miles..! And you can't build enough, low rpm power to pull them well.

BUT, most daily driver cars, like to be run. I have to admit, I now own a 4 cylinder offshore car. I drive it like I drive my motorcycles, it hardly ever spends much time below 3,000 rpm. NO...lugging..! While it IS sort of a factory hot rod, but like I said, 3,000 or above.

To make usable power at lower rpms...you NEED to have a camshaft, cylinder heads, intake manifold and fuel injection/carburetor, to run at that lower rpm. Otherwise, you've built a bastardized combination that really doesn't know what its supposed to do.

Rough guess, I'd say that 95% of the cams, and induction systems in general..."want to run", not shuffle around like a 90 yr. old man.

Mike

 

The 390 in my '63 always has a smile after a good run. Maybe it's me smiling, but still ...

 

Kind of a toss up I think.

I've broke a lot more motors trying to make then "run" that I have babying them, but maybe instead of "making them run", I was "abusing them", and I'm not so sure I know what "babying them" means.

I think the care they have been given makes a lot bigger difference then how they were run, but how they were built also makes a big difference. A high compression, big cam, performance motor will fair a lot better being run through the paces then it would be putting around. There could be a pretty thin line between putting a car through its paces and abusing it. One is good for it, the other is not so good.

Another form of abuse is when a motor never gets driven long enough to reach operating temp. My 84 YO mother drives her minivan from her house to the store 6 blocks away then back home, or it gets driven to the coffee shop two different times a day, about 6 blocks round trip each time. Really, it gets driven a total of about 10 miles a week in 15 trips out of her garage. Her ride never reaches operating temp. About one a month I'll take her car and give it a good 20 mile run. You can feel the difference in the way it runs from the start of the 20 mile loop and how it runs after the 20 mile loop. Gene

 

"A red-line a day keeps the mechanic away"

 

Of course no one would want to buy a beat up engine, and a carboned up engine that has never been exercised comes with different issues, working with the power valves dropping raw fuel into the engine also has issues, but a good clean run is good for the engine, revving the engine till the rods are laying loosely in the bottom of the oil pan is also counter productive,,,, you get the picture.

 

All the more reason to run the shit outta mine.

 

I worked for 35 years in engine engineering.

Engine wear is, to a large extent a function of fuel burned. I once plotted ring wear against fuel consumption for a sample of around fifty engines of the same type.and confirmed the correlation. An engine running at, for example 6 mpg would have the same ring wear at 100000 miles as the same build running at 17 mpg would have at 300000 miles.

Oil analysis says the same thing. High speeds and high loads increase engine wear. Always.

Excessive idling creates its own problems.

 

That depends entirely on the engine , how its controlled ( fuel , spark) & how much " work" ( stress) is being placed upon it .

 

More like 1350 RPM
A modern car eg: a C7 Corvette can cruise comfortably 63mph [100kph] at 1350 rpm.
A combination of resistance [mass and drag] vs hp [cylinder pressure x rpm] and gearing

You could easily build an engine to meet these demands.
Short duration cams, long stroke, high velocity ports, higher overall gearing, wider trans ratios.

Basically a 305 Chevy in a hotrod

 

My DD 5.9l 6700lbs p.u. cruises all day @ 1400 r.p.m. & has done so for 247k miles , can't be too awful bad for it ..and its really outdated by today's standards . I'm afraid the days of 3000 rpm cruiser is long gone ( except here!) The biggest changes are in cylinder head design & electronic engine management .

 

Apparently you haven't been in the drivers seat very long or just haven't driven different kinds of vehicles under different conditions..?
There's alot of variables that could and should be factored in to get an accurate answer.
First to answer your question fact or fiction? I would say fact.
From there it can go several ways, like what one person considers working an engine ,the next will say that your running it to hard.
If its a purpose built engine ...what was it built for?
A all out race engine isn't going to run rigjt and probably will not last long if you were too just drive down to the store and , it could be alot of fun or alot of trouble.
And if your looking at a engine for the purpose of hauling stuff around in your pick up and be able to afford gas ..then going small for the possible better milage isn't all ways the answer.
In the end the smaller engine may have to work harder than say a big block engine so you are not really gaining anything ...so go big and get done faster...and of course there is alot that effects that over all weight, working rpm's, gear ratio....
Years back l had a Chevrolet Luv pu. purpose for mileage B and F to work and to haul some things...best mileage was about 15-18 mpg and kind of a pig , 4cly and 4spd.
Engine went bad ..oh its time for a V-8, a friend was parting out his asphalt circle track car had a fresh 327 11 to 1 30 over bore all balanced pretty bumpy solid lift circle track grind cam...aluminium flywheel and a M-21 4spd .
I bought it put it in the truck along with a 9 inch ford rear end with 3:70 gears cut down by the Dutchman when he still worked out of his garage.
The truck run good and strong ,hauled what ever I put in it with ease, drove it back and forth to work every day for over 2years ,and it would pull about 22 mpg and had plenty of passing power... then the new 85 Monte Carlo SS came out ..had to have one, put a bigger sbc with 13to1's 60 over and alot of other stuff and papers saying 597 hp at 7200 rpms in the truck ...it was just good for long cloady burn outs then and I didnt really have to work it.

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Ah! but was that body sitting at a desk for 40 years or doing heavy manual labor or something in between.

 

Just to be clear, I am a journeyman automotive mechanic (same as what you would call ase or red seal certified in the USA. I'm almost 50 years old have driven and owned alot of vehicles, as well as repaired alot of engines.....mine and customers. I will also tell you that I am a human and make mistakes and have made my share of them (sometimes starting a thread on the HAMB is one i make). I certainly don't profess to be an expert in anything. I was really just asking if any of you have heard the same stories and have stories of your own. There are far too many factors involved that determine an engines lifespan, durability and fuel mileage.

 

I think the idea came from the time when engines weren't " tight" like they are today ,they pumped oil past the rings & the carburetors dumped extra fuel down the cylinders , the fuel had lead in it & the oils weren't as refined , basically they were dirty engines . Taking them out and " running" them blew some of the crap out of the combination chambers & cleaned the plugs , therefore after one of those sessions , the engine would run better for a while , therefore the saying , " they liked to run" .....

 

I call BS - kinda like the "need" for backpressure.

Set the car up to run where the engine makes the most torque and it will perform well. Once you get outside that range performance suffers. (70's vehicles with ridiculous highway gears, big cam and highway gears or no stall or heads that dont support cam)

I do agree with " blowing the carbon out"

Engine wear is relative to use. 11-1 compression and a big cam needs to turn rpm, just plan on new rings and bearings every few years. Crank polish, light hone, file to fit rings, and a valve job are a lot cheaper than blowing it up. Just consider it the 25,000 mile service - cost of going fast.

 

There are certain givens with engines, with drive trains, and drive ratios. An engine no matter what kind of parts go into the make-up, short stroke, long stroke, long rods, short rods, design of pistons, compression ratio, cam specifics: lift, duration and relationship of intake to exhaust, type of ignition and spark (and scatter) and rotating mass of flywheel/torque converter, gear ratios to final drive and/or overdrive, circumference of rear wheels as opposed to height from center of axle, what mass the air sees the vehicle as, and so on that determine where the sweet spot is for a given rpm vs speed vs best fuel consumption. GENERALITIES about what is best for the gander often neglect to take in consideration it is the goose that carries the egg. So, to all who want to discuss specifics, at least some of the categories included previously would therefore seem sacrosanct to a discussion about where an engine lives best, doncha think? As to noise and all that, studies have been made to determine that decibel level output and horsepower/torque are not related. Science is about specifics, and being able to quantify before you qualify --- this is why engine builders have mule engines that see a variety of configurations in order to determine if specifics can be determined from generalities.

 

All I know is.....I have an off topic duramax, winters are cold and long here, the first time I hook the old girl to my travel trailer in the spring, there is a noticeable difference in the before and after the trip. Seems the trip is needed to make it run as it should, so, who knows?

 

I agree completely. This is a pretty well accepted concept in the heavy equipment/heavy truck industries. Cat has pinned engine life to fuel consumption, and even has a number for the gallons of fuel consumed for expected engine life (I don't recall what it is offhand); and fuel consumption per hour, or mile, will change depending on the duty cycle. A lighter duty cycle will result in lower fuel consumption per hour/mile, and longer engine life, and vice versa. So the company I work for also use this for optimizing maintenance intervals, we even coined and copyrighted the term "Severity Based Maintenance". So oil changes are scheduled based on severity of duty cycle, or fuel consumption. But yes, fuel consumption is the ultimate arbiter of engine life.

 

Caterpillar also used fuel consumed as an indicator of engine life. Basically, if the engine has consumed X amount of fuel, it is due for a rebuild.

 

I think if each time they are driven they are brought to operating temperature, the cruise along engine will last longer. However, the hard working engine may be more fun.

 

I'm sure your compression went up from getting the ring seated nicely. Also the trans and rear end loosened up a bit from being broke-in.
PCM parameters did some learning too.

 

This is cool info. Makes sense.

 

Well excuse me....I wasn't trying to knock you down or discredit you . I just figured that someone that had some miles under there belt would kind of have a answer to that question already for them self.
Its nice too have some back ground info on you now, I now know that you where just looking for some small talk and or just have a conversation on the matter....wait a moment.?
Answer a question,,.? , yes..I did that.
give a personal thought or story on why or what helped in determining your answer.?..did that...?
Say that there are many variables to consider when trying to give a more accurate answer.?. I did ..same as you did in your return comment.
Give a example or story of your thought on the subject..?.did that.
Say that you are unprofessional and or stupid...? did not do that.
In the end , did "you" the OP determine a answer for your original question..? I think you did...as you stated in your return comment ..same as I in my first response.
So I ask you...OP....fact or myth..?


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Insofar as my experience go, 60 now, I've always driven my cars accordingly and not pushed the limits too far depending on what had been done to the engine. The 5lt in my 35 Chevy is a rebuilt stocker so I don't push it too hard, need to consider the trans and rear axle (3.54:1). I wouldn't its limits too far.
The 383SBC going into my 46 Olds will go harder due to having more work - heads, cam, exhaust etc however the trans and rear axle (3.73:1) have been built for the extra HP and performance. The 427 in my 64 Fairlane goes hard however around town it can be a slug due to rear axle (4.11:1). The engine requires more gear (4.56:1) to realise its potential. The best is out on the highway where they can stretch their legs.

 

As in most things, “moderation”is the answer!






Bones

 

A corrolary to that is most engine wear, per SAE research in the 80's happens during cold starts, due to oil drainback.

 

Never could verify that was the primary cause of engine wear. Possibly true on old, carbureted engines that had lousy air/fuel control cold, and thermostats that leaked and caused poor combustion and allowed acids and slugs to accumulate.

We spent tons of money instrumenting engines with radioactive tracer in rings and bearings, and concluded speed and load (fuel rate and piston temperature) were the major players.

Did have some engines with old school chrome rings that liked to microscuff on cold starts (full throttle starts at -20 F). High crack count chrome helped, and modern ceramic facings pretty much eliminated it.

 

My hemi does. If i let it sit very long, it is hard to start, lifters are empty and clatter until they fill up, is sluggish until it warms up. If I drive it often it snaps to life instantly and is very responsive right off the blocks.