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Discussion Starter #1
Hi,

I'm sure there are/have been lots of threads on this issue but I couldn't find a specific one so I apologise in advance for starting another (redundant) thread .

I appreciate that nowadays most new engines require little running in (unlike those of yesteryear which soon filled sump with iron filings etc.) but I seem to remember that as modern (especially synthetic) oils are so good that 'normal' running in (< 3500 rpm for first 1000 miles) may result in glazed bores etc. I vaguely remember a school of thought that short spells (non-laboured) of high revs in the first hundred miles or so prevents this?...or I could be typing a load of 'tosh'

Any comments anyone?
:?:
 

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The manual says that once the engine is to temperature there is no need for any special 'running in' treatment. The obvious flaw in that instruction is that the XF doesn't have a temperature gauge so how can you tell when it's up to temperature??? I would suggest that 4 to 5 miles would be sufficient.

Beyond that I would suggest common sense. For the first 2000 miles I kept mine below 3000revs. Once past 2000 miles I occasionally pushed the revs higher (3500 and above) but not under heavy load. It's now at 4000 miles and the rev counter does see the upper limits of the rev range about once a week but again, not under heavy load... in other words, it's not being thrashed.

The thing about V6s is that they are two nicely balance triples sharing the same crank - it's what makes them so smooth. In my experience V6s are happier to run at higher revs than a straight 4, for example. The only improvement in engine configuration over a V6 is a straight 5 which fits the maths perfectly. The only problem with them is that they are so smooth that they are quite dull to operate...
 

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I agree with the notion of varying revs, workload and therefore temperatures at all times but there are two points that made me frown:-

Not less than 2500 revs when cold... why? a cold engine needs treating gently because all the moving bits are a different size to what they will be when warm.

Not less than 3000 revs when warm... again, why? I understand the point about keeping the turbo in it's operating range but unless you intend drawing on the power the turbo can produce then whats the point of keeping the engine running in the upper rev ranges? It's like saying "i'm going to leave every electrical item in the house plugged in and on stand-by just in case I need to use it. An engine under light load at 3000 revs will use more fuel than one under light load at 2000 revs so unless you want to draw on the power in the next few seconds you're simply wasting fuel.

My advice - having driven and operated diesels all my life (from small cars to 3500hp two strokes) is...

Treat them gently when cold.
Let them work in the lower rev ranges - it's what they're designed to do.
If you want to get a move on operate the engine between peak torque RPM* and peak power RPM*. Use the higher revs for times when you need to get up and go.
Use low revs in low power demand scenarios - no need to rev it and therefore burn fuel - for the sake of it.
If you've worked it hard then let it idle for a couple of minutes before you stop it - this gives the turbo bearings a chance to cool down.

* One thing that has frustrated me with the XF is the lack of a power/torque graph. You can find dyno graphs for the engine online which indicate the peak torque is 3000 revs and the peak power at about 4000. The torque on the 2.7 does tail off quite dramatically after it's 3000 peak so I would suggest that the car will be in it's most lively state between 2700 and 3500 revs.

http://www.millennium-jag.co.uk/downloads/Graph-J66.pdf
 

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I wondered about those 2 points and tried to make sense of them too.

My take on it was:-
Rules that apply for the life of the car
-When the engine is cold rev the engine to at least 2,500 rpms.
- means while the engine is cold try to take it above 2.5k at some point following the 'vary your revs' rule, personally while the engine is cold I wouldn't take it above 3k, giving you a 500rpm bandwith to play with.

Rules that apply for the life of the car
-When the engine is warmed up rev the engine to no less than 3,000 rpms.
- means that when the engine is warm vary your revs but at some point ensure you break the 3k barrier.

but again this is my interpretation of what was written.
 

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Discussion Starter #7
Hi,

Thanks for your inputs. Variability is the key :!:

I always vary revs....paddle shifters are good for this by switching between gears at constant speed etc.

So for first 1000 miles I think I'm going to keep varying the revs up to 2500 for first 10 miles (warm up from start) then vary up to 3500 rpm with the occassional 'push' (downhill, not under load) up to 4500 rpm. Not going to be hard on brakes though (250 miles...unless I have to) :eek: )

At 1000 miles it will be run in ;) . Getting first drive next Monday as transferring from one Dealer to another for PDI etc....can't wait :) :) but in my possession proper on 25th :) :)

Another good thing about this deal was that the value of my p/ex (ML 320 CDi Sport INCREASED by £750 :) :) :)

Is the temperature gauge white smoke from engine compartment then? :shock: :shock:
 

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Ha, yes. Colour coded visual clues...

Light blue exhaust smoke means engine is cold.

White smoke from bonnet means engine too hot.

Red glowing exhaust means someone has been playing with the fuel pump:)
 

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Found a power torque graph for the 3.0S variant compared to the 2.7
 

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I used to work on diesel engines and have experience rebuilding and testing them. We did have some trouble with glazing of the bores at one time but this was put down to a combination of a new oil and the running in duties being performed by the engine which were fairly light loads and running fast. We consulted Castrol and the engine manufacturer and they came up with a running in programme to be carried out on a dynamometer (ideal situation I know).

Basically the engine was loaded with increasing speed and load over a set period of time with varying bursts to the next loading and back off again and so on until a period had elapsed and then the next loading was adhered to and so on.

In short it was found that what is bad for a diesel engine during running in also known as the bedding in process is sustained high speed combined with low torque loads which will reduce the piston ring loading and make the piston rings polish (glaze)the bores producing blow-by.

I know the engines are bench run, lubrication and machining tolerances have moved on and so running in should be less of a process than it used to be but I think that there is some logic in following the principles.

I think that stop start driving would best emulate this practice rather than prolonged motorway driving on cruise control. Take the country roads! :)
 

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I have seen a lot now about running in etc....too be honest...didnt get all of it.....hey guys..we are not techys here !! :)

in any case.....no one seemed to dwell on gradient factors....here in Switzerland...its a mountainous country.....are there any restrictions to running in whilst taking on high gradients...say going uphill from 500 metres ASL to 2200 metres or so?

please reply in plain English !! :)
 

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If you are looking for advice on running in your XF let me give you my views in plain english, get in it and enjoy it! You can't take the engine to a point where it will be damaged, the automatic gearbox won't let you, it will change before you you reach the kind of revs that will do any damage, especially in ordinary mode, ignore sport mode for the first 1,000 miles or so. By the same token if you are going up hill it will put you in the right gear. So as I said, get in, sit back and enjoy. ;)
 

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philayl said:
If you are looking for advice on running in your XF let me give you my views in plain english, get in it and enjoy it! You can't take the engine to a point where it will be damaged, the automatic gearbox won't let you, it will change before you you reach the kind of revs that will do any damage, especially in ordinary mode, ignore sport mode for the first 1,000 miles or so. By the same token if you are going up hill it will put you in the right gear. So as I said, get in, sit back and enjoy. ;)

You might also have referred to one of your earlier posts philayl when you kindly copied text from the manual on this matter. I have copied it below:

From the Car Manual


RUNNING-IN
Apart from a few precautionary
recommendations, there are no strict
running-in procedures for this vehicle.
By observing the following advisory
precautions you will ensure maximum engine,
transmission and brake life for your vehicle:
Engine
• Allow the engine to reach operating
temperature before operating at engine
speeds over 3 500 rev/min.
• Vary the speed frequently.
• From 1 500 kilometres (940 miles)
onwards, gradually increase performance
of the vehicle up to the permitted
maximum speed.
 

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Thought I would keep it simple pekem! ;)
 
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