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-   -   ARTICLE: How to Run-In your new car (https://www.team-bhp.com/forum/owning-car/67729-article-how-run-your-new-car-41.html)

Ahaa!! Its a little to much for me to digest to hear this from you!!

Why don't you come out with the technical aspect of it and enlighten us by explaining the real consequences of Lugging!! please:

My little knowledge tells me that, "Lugging" the engine causes enormous amounts of stress on the "Connecting rods" and eventually the " Bearings". Which IMO is not a good thing to do!

Chief

When i use an OBD port software and find engine parameters, here's what is happening.

I am on a highway, with speeds 80-100 kmph, and about to face a steep incline. Current readings: Engine load:40%, instantaneous kmpl: 26 and i can see fuel flow counting slowly(hex counter).

Now as i climb the incline, speed reduces to 70 kmph(for the same given throttle), now engine load:50-60%, instant kmpl: 18.

Frustrated with the speed drop, i floor the pedal. Now speed increases marginally ~75 kmpl, lots of engine noise, engine load:80%, instantaneous kmpl: 12-13. Oh and lot of black smoke behind the car and soot on the bumper to clean.

If i ease the pedal, downshift, maintain about half pedal, i feel that i am in the power band- engine eager to pull, engine load:40-50%, kmpl: 15-16.

So my understanding why not to lug: it is bad for the fuel economy. Now i am waiting for your reply from the engine internal point of view.

In technical terms, lugging is when throttle input does not cause any accleration. Like climbing a hill in 4th gear at 40kmph, with speed slowly falling.
It puts pressure on the con rods(lower part of engine). But I am not sure if modern diesels have this issue.
As for petrols, I think it causes knocking, which is explosion(compression ignition of petrol) which anyways is not a good thing.

From a chemical point of view, lets say you are in high gear.
You floor the throttle, and it puts in more diesel into your chamber.
So instead of X amount of diesel 4X amount of diesel is being ignited
When you are not lugging, the diesel coming into chamber is also causing engine to spin faster.
But in this case, the diesel explosion, happens, but the cylinder is resisting.
This is like holding the tires and try to run the engine.

In my diesel, I have seen when this happens, I get lot of black smoke, so all the excess diesel does not ignite. Which is a good thing. However, if all the diesel was igniting it would be more problematic.

I hope I have not confused matters up, let me summarize
Putting fuel into engine and igniting it is damaging the engine (miniscule damage).
The more fuel you put, the faster your chamber should expand, i.e. the faster the piston should move down.
Piston moving down converts the chemical energy to mechanical kinetic energy of car in motion.
Now what if you caused the explosion and held the piston such that it could not move(lugging). It would then hammer the mechanism.

Boom Boom Boom

I guess modern engines will expel unburnt fuel, which will take the steam off.

Other good approach is electronic throttle which will detect that more fuel is not going to make me go faster, so irrespective of throttle input I will limit the amount of fuel which can be injected into the engine.

Regards run-in of diesel cars you mean I should run-in for half of the earths circumference!? No offence but don't you think 20k kms is too much of a run-in?

Seeing this question coming from you makes me think you're actually trying to lead us to the truth :)

Here's the little I know (I could be way off base, however): the bearings used for the crankshaft are directional, and turning them the wrong way can destroy them in very short time.

When the engine powers the wheels, the crankshaft power overcomes the resistance that is contributed by the transmission/wheels/weight, and turns things the right way. When lugging, the engine isn't in its most powerful zone, and there is a tendency for some reverse moment to come in from the wheel/transmission. Nothing significant, but just fractional resistance/backlash.

While this is insignificant, it can add up to bearing damage. While it may not result in massive oil leaks, it can result in minor increase in oil consumption, or general wear and tear as the bearings are no longer perfectly aligned.

Now tear me apart and tell me how I'm wrong :)

Frictional resistance/backlash, Yes! But the entire assembly rotating the other way,with the timing belt connected and in sync with the valvetrain! I'm not sure how would it rotate the other way while the engine is running!!

I'm not saying the crankshaft will change direction :). Obviously not. That's why I said "Nothing significant, but just fractional resistance/backlash."

I'm referring to just the momentary reverse pressure/resistance for those instants when the engine power isn't overcoming the wheels. Basically, the precursor to a stall.

Just to follow up on my earlier question, it was in relation to very firm statements such as this one:

That made me wonder what bogging/lugging really is and why would it be so damaging to an engine? I think I begin to understand what bogging/lugging is.

I liked this definition quoted by one of our members:

In itself this is where part of the problem (or the understanding of the problem) already begins. Because this situation can occur across a huge wide range of engine loadings. You could be barreling up a hill, in third and revving 4500rpm and pushing the accelerator and no acceleration happens, i.e. lugging.

Or you could be going up a different hill in third revving 1500rpm and pushing the accelerator won't do a thing. In both scenario's you are likely to experience the same symptoms, but maybe with somewhat different severity.

So what is it that under these sort of condition is, apparently so damaging to an engine. I don't think I have heard a good explanation yet.

Yes, your FE will go south, yes you will belch out some soot, but neither is particularly damaging as such, or at least no permanent damage.

It has been suggested that the crankshaft would be loaded up heavier. But how can we be sure it is so. Roughly speaking the crankshaft, bearings and conrod loading is a function of RPM and fuel injected. But its also obvious that combustion condition during lugging are not particularly good to put it mildly. So how do we know that essentially the force on the piston during lugging is greater than under normal full load conditions? I don't think we do, and my gut feeling is it isn't either. (But I'll happily let someone proof me wrong or otherwise)

Short version, I think it's largely a myth, stemming from some sort of better safe then sorry type of approach.

The damage (if any) will depend heavily on the condition under which lugging happens (i.e. what rpm, what loading etc) and for how long and how often.

Here are my thoughts what could get damaged over a long period of time:

Bad combustion can also effect the piston, piston ring, cylinder liner lubrication, so expect some additional wear and tear there.
As mentioned by various members, during lugging you feel the engine sort of shuddering. As I stated before, I'm not so sure that that will immediately cause problems with bearings. But some of the gears, i.e. transmission, gear box etc. it might. There is a phenomena called teeth clattering and it is where two meshing gears don't maintain sufficient pressure to keep optimum lubrication going. It tends to happen in gear boxed that don't get loaded up properly, say a PTO shaft that is running for a long period with no load. I've had such a situation on one of the gearboxes of a ship with (near) catastrophic result.

There might be a few other areas as well. But, without real data it is a bit guessing in the dark I'm afraid. Never the less, the old better safe then sorry is always a save bet to play. Even if we don't understand why.

Jeroen

Hello everyone. It's a repeated question regarding a new car... but, can anyone inform me that do I need to run in the engine of my ANHC CVT? I'll be getting the car next week and plan to go on a road trip close to 1000 km in total... What care should I be taking? Should I get the 1st service done in between the trip? And can I push the engine right from the start?

Congratulations on ANHC! :)

Some say that modern engines do not need running-in. If you ask my opinion, you need to do it!

• Keep things sedate till the first 1000 kms;
  
  
• Keep varying the speeds often and do NOT keep maintaining the same speed;
  
  
• Give a break / halt of 10-15 minutes after a stretch of drive;
  
  
• Do carry a can of oil (just in case, though not needed) and oil filter.

The first service is at 500 kms or 1000 kms?

Anurag.

When in doubt, check the manual! If still in doubt follow Anurag's simple rules, unless the manual mentions something different.
Enjoy your new car!
Jeroen

Thanks a4Anurag and Jeroen. That will come handy. I don't know about the first service schedule, but I think that it's one month or 1000 km... The three free services will get over in the first 6 months only. This has been put up on the ANHC official review thread.

Is there any run in period for polo tdi? If so, what all should be taken care of?
My car has done 720km till now. But i have never revved it beyond 2000rpm.

1000 kms is common for all cars. So do keep it running in for another 280 kms after that open up slowly.

If you don't mind, once you complete 1000 kms change the oil filter.

Anurag.

Please check what the owners manual says about running in. Cant hurt to take it slow, but the only place where you will get solid advise on this is the official owner manual, rather than the Internet.

Jeroen