Engine operation at lower revs - damaging or not?

[ylop]

Couple of friends of mine (both mechs) had this debate in a pub years ago

the most scientific results are always obtained by people without actual data debating in the pub.

Getting meaningful data requires having multiple engines, subjecting them to different approaches and running them to failure. That’s a hugely time consuming and expensive process, which may not even yield information that directly translates between designs.

Old engines only had the owners reports as to how it had been treated when failure was assessed. Modern engines presumably have a lot of electronic logging that a smart company could use to work out the ideal approach (if they cared - perhaps their motivation stops after the warranty period).

It strikes me that even if one approach is optimal it may be more or less important depending on climate where it is used or the installation. Seems slightly odd in today’s modern electronically controlled engines that there isn’t a “cool down setting” which would run the engines in neutral at the correct rpm either for a set time or until some sensors report everything is good to turn off.

 

[Fire99]

Couple of friends of mine (both mechs) had this debate in a pub years ago (albeit about cars) they both ended up agreeing that a cool down period is a good thing and spanking the engine from day one was also a good thing (at varying rpm)

Years later I watched a (top gear style) motoring show on Youtube that tested the running in thing! They got two brand new diesel cars, spanked one and carefully ran in the other. The one they spanked ran better and made more horsepower on the Dyno.

Wish I could remember the channel!

I have ridden motorbikes all my life and have given them the beans (full RPM on track) from day one and have never has an issue.

Has anyone here heard of an “Italian tune up” There is something in that too.

I remember the "Italian Tune Up".. Basically thrash the backside off the thing. Probably works.. haha
All I can see categorically from owning more engines than I can count, other than making sure you change the oil frequently, ALL my engines have been happier doing lots of work for long distances. They've run smoother and given better fuel economy.. (Petrol and Diesel). Worst thing for an engine is leaving it sitting around for months on end, in my opinion.

 

[ingenious]

Dunno about diesels but apparently EVs can benefit from a good trashing:
https://insideevs.com/news/764150/ev-battery-flooring-it-good/?

 

[spannerman]

the most scientific results are always obtained by people without actual data debating in the pub.

Getting meaningful data requires having multiple engines, subjecting them to different approaches and running them to failure. That’s a hugely time consuming and expensive process, which may not even yield information that directly translates between designs.

Old engines only had the owners reports as to how it had been treated when failure was assessed. Modern engines presumably have a lot of electronic logging that a smart company could use to work out the ideal approach (if they cared - perhaps their motivation stops after the warranty period).

It strikes me that even if one approach is optimal it may be more or less important depending on climate where it is used or the installation. Seems slightly odd in today’s modern electronically controlled engines that there isn’t a “cool down setting” which would run the engines in neutral at the correct rpm either for a set time or until some sensors report everything is good to turn off.

There is a ‘sensor to report everything is good to turn off’ its called a careful owner with mechanical sympathy although they are getting to be very rare IMHO with regard to modern boat and car owners.

 

[aerobat]

Like previously said , the reason for break-in is to eliminate microskopic uneven areas on the cylinderwalls and achieve a good seal between the rings and the cylinderwall . The best you can do is indeed to floor the engine hard when new because this causes the greatest cylinder pressures and ring seating .

You should do it in bursts and allow for some cooling down periods of hotspots between the rings and the cylinder

to baby the engine will result you are more polishing the cylinder with the rings which gives more oil consumption and less compression after break-in .

The reason no car manufacturer recommends this is

- no manufacturer wants to ask his customers to drive agressivly on public roads
- forcing the engine continously ( without giving it a short cool down periods ) gives the risk of a local breakdown of the oil film on hotspots .

 

[New Boater]

I remember the "Italian Tune Up".. Basically thrash the backside off the thing. Probably works.. haha
All I can see categorically from owning more engines than I can count, other than making sure you change the oil frequently, ALL my engines have been happier doing lots of work for long distances. They've run smoother and given better fuel economy.. (Petrol and Diesel). Worst thing for an engine is leaving it sitting around for months on end, in my opinion.

100% agree with that. I run diesels to death regularly as a long distance owner/driver

Good oil is king.

 

[Supertramp]

There is a ‘sensor to report everything is good to turn off’ its called a careful owner with mechanical sympathy although they are getting to be very rare IMHO with regard to modern boat and car owners.

Agree.

I have a 17 yr old Beta 60 and cruise at 14-1500rpm (at sea). Max power is 2700, max torque 1500. It will and does run all day. I have never had to top up the oil between changes, no smoke. Once a year maintenance at 100-150 hours.

Treat it with respect, watch and listen for warning signs and it'll be there when you really need it.

I've run cars the same way but the advent of EGR's and DPF technology didn't sit well with a gentle use approach!

My first company car was driven like I didn't own it and lasted only 100,000 miles!

 

[jrudge]

I doubt it does much / any long term damage but boat diesels are more sooty ( given age I suspect ) than cars so my view is they do need a decent run sleceryvnow and then to burn that out of the engine / exhaust system etc.

Cars need a run to renew the dpf

 

[Alicatt]

I doubt it does much / any long term damage but boat diesels are more sooty ( given age I suspect ) than cars so my view is they do need a decent run sleceryvnow and then to burn that out of the engine / exhaust system etc.

Cars need a run to renew the dpf

We had a 100km/h limit put on the motorways for a while - save fuel etc. The Netherlands still has during daylight hours, traveling at 100km/h for hour after hour caused the dpf to clog up, a good hard run on an autobahn without a speed limit did a world of good and the dpf fault cleared and the car is running as normal again. The tech in the garage said take the car to Germany and give it a good hard run that will clear the dpf, so I did.

Same with the boat, a good run with the turbo up to speed and the engines stop smoking, then it's the hour back to our haven at idle speed undoes all that hard work
We did about 100nm over the last 3 days with some de-restricted zones where you can get up to speed, boat was running well and giving good speed per RPM, no smoke and no burnt oil smell in the cabin either

But now I need to look at the turbo intercooler and the gearbox cooler as I think they are partially blocked on the Stb. engine, still flows a good bit of water but not enough for a long hard run, flows about half of what the port engine does.

 

[Alicatt]

The other thing was that we are running diesel without any bio-diesel in it, the fuel station specialises in non bio diesel for the older freight ships on the canals.