Running in a Diesel engine

[Clan]

new racing engines obviously cant be run in on the road for 1000's of miles , They are given a few laps around the circuit at moderate speeds to bed in the rings , oil changed and off they go ...

[Manic-me]

Thanks for your posts - seems to polorise opinions.

Thanks Kerry-T for you link
http://www.mototuneusa.com/break_in_secrets.htm

I've been pointed at a couple of others
http://www.civinfo.com/wiki/index.php?title=Running_in
http://vwwatercooled.org.au/newforum...hlight=running
and
http://www.honestjohn.co.uk/faq/faq.htm?id=32

Focus looks to be on the piston ring seal. Avoiding constant revs for the first 500 - 1K miles, perhaps longer and regularly using the "full" rev range with the limit increasing from 3K revs based on milage.
Its funny really - I would have though sitting on the motorway at 2K revs would be ideal, apparently not.
Its going to be hard to avoid the motorways ....

..MM

[John Davies]

Normal advice is to put a rebuild diesel engine under a reasponable loading for 500 miles with running in oil in - not tank it but switch from say labouring it up a hill to going moderately fast down the other side. Running in oil - straight mineral oil with additives to create mild bore wear can help. Synthetics or semi synthetics are a no no.

Factory engines these days are honed to perfection and then given a version of running in oil before being sent to dealers whereas most rebuilt engines are now done to quite the same spec,

Regards


John D

[gillberry]

In the early 90's we had 2 transit vans delivered new to work , one all of us younger guys thrashed and it drove sweet plenty of acceleration the other an old boy drove nice and steady this one had no go and was a nightmare to drive . When I test drove an xc90 recently that had 500 miles on the clock and felt like it had plenty of go .

My new xc90 is due middle of next month and I have to say I hadn't really thought about running in until I saw this thread so I'm interested in what the general consensus is .

[Dobby]

Hi
When i picked up my new V70 D5 geartronic last sept I asked about running in and was told it didn't need it, just dont take it to the red line for the first few miles. One thing don't sit on the motorway first of all drive on A and B roads so the engine is going up and down the rev range and the gearbox etc aren't just sitting at one steady speed but working, don't 'labour' the engine in the wrong gear though.
Read years ago, before diesels where about much over here and engines had to be run in, that the french drivers when they got a new diesel thrashed the n*ts off it straight away as driving it like the preverbrial vicar caused 'glazing' in the barrels which was bad and never went away, don't know how true it was.
Took my car for a good drive straight away, and never touched a motorway.
Enjoy the new car.

[gillberry]

Searched Volvo's website but found nothing so decided to e-mail them . This is what came back
"Our vehicles do not need running in like they did in the past. This is
carried out before the engine is fitted at the factory. We would however
ask our customers to be cautious in the first few months bearing in mind
that the vehicle is brand new. We also offer a free 3 month quality
check and would strongly advise our customers to ensure this is carried
out."
Hope this helps .

[MRDART]

When I was riding sidecar motocross the way to run in an engine was run it until water temp is ok and then just ride it like you stole it... (2strokers)

[alenas]

I was driving go-carts and after changing rings - we would always do run-in (normally you leave a go-cart for 10 minutes running on idle and then gently drive for a few days).
If we would not run-in properly - we would have to change rings after 1 race...
But I guess this innitial run-in is being done in a factory - so really there is no need to worry about anything these days. Also probably they cover pistons with some special coating that lasts for initial 500 miles and it keeps friction to the minimum.

[amsoil]

Even well honed bores have a series of peaks and troughs on the surface. This helps with oil retention and lubrication of the pistons and rings. The 'quick thrash' method came from dynoing race engines where it was found that a quick initial 'hard time' basically removed the higher peaks quickly and thereby aided the polishing in (running in) of the engine. There are of course many variables. We are talking about tens of seconds here rather than days of general abuse. Ring and bore technology are now such that glazing of bores should not happen and that sufficient running in should be accomplished in 500 miles or a max of 2,500. This great difference is because engines are not the same nor is the driving likely to be. It is generally accepted that motorway driving during this period does not assist and that the varying of load speed and revs can assist.
Do not put in a synthetic oil, especially Amsoil, until the running in period is complete. A top synthtic will quickly stop measurable wear and that includes any further running in.
I am aware that some manufactures do put in their 'synthetic' oil from new; perhaps this says more about the oil they offer than anything else.

[Sanzomat]

My experience of diesel engines is that they continue to get better over many miles. My last 2 cars (2.0tdi 140 Audi and 1.9dci 120 Renault) both improved steadily in smoothness, performance and fuel economy right up to about 50k miles and then levelled off.
The process of running in is simply that of knocking the high spots off the various metal parts, including bearing surfaces, piston bores, cams etc. however well they have been machined/honed there will always still be peaks and troughs if viewed under a microscope. The main high points should go pretty quickly but there will be a degree of diminishing returns until eventually everything is smooth. (although as previously mentioned a good fully synth oil may prevent any wear and leave you with some peaks and troughs for many thousands of miles). The main reason for a running in period used to be that the initial "roughness" of the bearing surfaces would cause friction that would lead to overheating. This overheating may be very localised and would cause the oil to deteriorate quickly and a combination of the "burnt" oil and the heat could lead to warping/twisting/uneven wear or even siezure of certain components. This is less likely due to improved machining and better oils/additives these days, hence the ability to thrash it out of the box without causing damage. Other purpose of initial running in is to improve the seal of the piston rings against the bores. The idea of gentle runing in but with a mixture of on and off throttle driving achieves this best because the rings are intended to rotate and thus wear evenly. Some believe that early full throttle will wear the rings in one place only and prevent them from rotating which would shorten the overal life considerably and lead to poor compression and high oil consumption.
My own philosophy is that it is still worth treating an engine with respect in its early life. A mixture of driving must be best with a variety of throttle positions and engine speeds but avoiding labouring and staying away from the red line in the first few hundred miles then gradually building up. I don't believe that steady motorway speeds do any harm but neither do they achieve much "running in" so you don't count those miles towards the running in period. I also think that every car benefits from a good thrash from time to time to blow out the cobwebs (the so called "Italian tune up")