Running an Engine Continuously at Low RPM.

If you are the one that is going only 60 km/h when you could go 100 km/h then go out of the way.

Is the traffic in Lahore not bad enough?

Just use a lower gear when going 60 km/h and see how long you can keep this up.

To answer the question: vehicle engines should be able to run under most conditions most of the time. Continuus running in a certain gear/rpm will not happen when driving a vehicle and particularly in a city environment. If in doubt ask the manfacturer of your bike. They should know the perfect conditions to ride it. But since life is only near perfect I would not worry too much.

Is your bike a diesel?

If an engine runs cooler than designed for long periods, especially years ago when petrol & Diesel additives were not as good as they are today (not forgetting the aftermarket products available for adding to the tank to help keep injectors, valves and cylinder heads clean), it is seemingly well documented that carbon buildup can happen.

I used to clean out car engines suffering such problems on a long,long hill on the A2 motorway, slowing down to say 20MPH (when no traffic!), selecting top gear and then flattening the throttle. This would cause extra heat and low revs....the best way to clean carbon off....

High revs and low speeds do not achieve the same effects....

This would cause excessive carbon buildup to leave the engine, at night leaving a glowing trail of particles on those engines with straight thru silencers....great fun!!

A friend of my Mothers had a small car that was particularly slow until after the treatment!!! It would last about 6 months......then I would do it again!! On her car it made a startling difference, it was because she never went over 40 MPH and a max of 10 min driving!!

I have to admit that with modern cars/fuels I haven't don it in 40 years.....not needed with normal driving when you occasionally cruise at over 100MPH for long periods I would guess....

A lot depends on the type of engine ( diesel / gasoline) and the design. Most diesel engines are slow speed and should be run full throttle for efficient fuel use and for proper lubrication. On the farm we had a Cat D2 and my first lesson in operation was WOT when working and limit the idle time as much as possible.

Working on diesel engines in particular some are more prone to carbon build up even plugging the exhaust. A lot also depends on the condition of rings and valve seals also a leaking turbo seal will contribute heavily to carbon build. I found Deutz to be prone to exhaust carbon build up as well as others but when working to rated capacity the problem was diminished.

A plugged exhaust if severe the engine will fire a few times then quit or will start but power is way off and black smoke out the stack. Automotive engines are designed for a wide range of operating conditions and speeds so they have much less of a problem but not immune by any stretch and a plugged converter is quite common producing the same or similar symptoms.

As I pointed out in the previous post traction engines can be run safely through their their whole rev range, however long idling periods should be avoided. Provided the engine is operated at the correct rpm for the speed of the vehicle,no problem should be experienced, with the proviso that the engine does not have a critical rev range and a large oil carry over is experienced. I have only personally experienced this phenomena in one diesel engine...........that was a Napier Deltic, these were fitted in minesweepers, and the speed of the vessel at which sweeping was carried out caused excessive oil carry over.

On the other hand gen sets are constant rpm engines and load can vary considerably and running on light loads is extremely likely to cause engine and fuel injector problems.

Curious also, with the mention of newer additives and modern engines…..Used to live in Los Angeles, purportedly the worst traffic in the U.S. …At times, especially if there was an accident or a stall, I would end up at 5-15 mph, 1999 Tahoe, 350 Chevy, for over an hour at a time. Speeds were often excruciatingly slow, summer time, 105 degrees and air-conditioning on, all the while doing the above speeds. What engine damage could be expected from that pattern? Would engine life be expected to be a lot less, or are the modern engines designed to endure this treatment? As far as diesels, I often see trucks at truck stops idling overnight, to keep their heaters going, and have wondered if the engines are designed for that low RPM operation, over such long periods of time? Thanks for any input. Curious minds….

One reason while "truckies" tend to leave their engine running is the thought that the majority of engine wear takes place on start up and when the engine is cold. There is considerable truth in this thought, because lubricating oils give maximum protection to the engine, against wear over a very narrow band of temperature. once the temperature decreases or increases outside of this narrow band, engine wear will start to occur, hence a major reason for thermostats. Not only for engine coolant temperatures, but for oil temperatures as well.

A good example of this is to take two vehicles, one owned by a little old lady who mainly does short runs and has done say 70 000 km and a taxi that has done 200 000 km. You will probably find that the engine with the least wear is the taxi, because that has been running 24/7 and the engine has always been at its optimum operating temperature, whereas the little old ladies car has barely reached its optimum operating temperature and has been continually started and stopped.........therefore a lot more wear has occurred in the engine.

True, in my of course "limited" experience.

Thank you. Makes sense… I have heard also, that the Synthetic oils have helped greatly with low speed driving routines and engine wear..Along with the Electronic controls of the new engines. Did I read it here, or??, that with the advancements in Electronics alone, an older stock big block motor could be brought up to close to 30 mpg, with out major modifications to the castings and building of the engines, meaning that rather than scrapping all of the old motors, retro fitting them would do more environmental good in the long run…Just a thought...

I am a long term believer in Synthetic oil and use it exclusively for my cars since the early 80's....

I find wear to be much reduced (no new engines in all my cars since then) as I have often made quite high mileages with basically little or no problems. No oil burning, even though most of them were "oil-burners", usually called diesel engines here!!

If you ever see or make the frying pan test for a mineral oil in comparison to a synthetic, you may become as convinced as I am!!!

Best of luck.

Even a whole day at such speeds will not do any damage of deposit much carbon. It takes months with cars, if not years of "normal" driving....