Running in a new engine

[VeeFource]

When a user manual states "avoid prolonged periods of steady speed driving for the first 600 miles", how long is this period? 10 minutes? 200 miles?

I understand it can lead to cylinder glazing, but how likely is this given motorway cruising is a medium load at medium revs? Or is it more that it just prolongs the running in time?

Thanks in advance!

[HustleRussell]

The more you vary engine speed and load during break-in, the faster it'll break in. Faster break in is good news for cylinder compression and oil consumption in the long run.
If you gave me a brand new car tomorrow I'd pretty much drive it normally, perhaps getting into using the top 2000rpm progressively. If I had to tackle a motorway drive within the first 500 miles or so I'd probably be quite annoying to follow because I'd be on and off the throttle like a minicab driver.
Steady engine speed (including idling) is good for running camshaft a in but not much else.

[Klippie]

Drive it normally...as with new or old engines let it properly warm up before giving it higher rev's, don't labour the engine in the lower gears keep it free revving.

I've done this for years and seems to be pretty much OK.

[VeeFource]

As long as the cylinders don't get glazed it would still have the same chance to bed in as well wouldn't it? Despite the longer running in time of course.

Just seems such a vague statement in the owners manual with no mention of the consequences disappointingly

[mattcambs]

Warm it up properly (as you would any engine) and then give it hell.

Unless you own the car. Then go a bit easier on it.

[nickfrog]

mattcambs said:

Warm it up properly (as you would any engine) and then give it hell.

Unless you own the car. Then go a bit easier on it.

So you're only mechanically sympathetic with cars your own ?

[rigga]

mattcambs said:

Warm it up properly (as you would any engine) and then give it hell.

Unless you own the car. Then go a bit easier on it.

Actually this, you need to force the rings into the bore to bed in properly, have a read of the mototune method of running an engine in, done all my bike rebuilds this way.

http://www.mototuneusa.com/break_in_secrets.htm

Edited for auto correct screw up ....

Edited by rigga on Thursday 8th October 23:11

[Ozzie Osmond]

One way to deal with this if you have to do motorway driving is to keep your speed the same but simply drive in different gears after every 10 to 15 minutes. With modern 6, 7 and 8-speed transmissions this is no problem at all. You can also simply turn off and get straight back on again at a few junctions to get the deceleration and acceleration.

[AdamIndy]

Depends who you talk to really, a lot of differing opinions. A lot of people swear by thrashing it from the first start, others below 4000rpm for the first 1000 miles. The only thing I would avoid is holding it a certain revs for any length of time.

[Impasse]

nickfrog said:

So you're only mechanically sympathetic with cars your own ?

Depends on the circumstances. A hire car? Meh. A lease car? Meh. A company car? Meh. Someone else's car? Like it was a newborn baby who needed wrapping in cotton wool and a 500 yard exclusion zone.

[twirly]

Klippie said:

Drive it normally...as with new or old engines let it properly warm up before giving it higher rev's, don't labour the engine in the lower gears keep it free revving.

I've done this for years and seems to be pretty much OK.

What he said.

[VeeFource]

Ok I'm really pi55ed off now having researched into this a great deal. We bought a new car and decided not to opt for an ex demo mainly because I could treat it well and be safe in the knowledge it's been given the best start for being long lived (I'd like to keep the car indefinitely!).

However, the first few journeys it's had were mostly motorways which seemed an ideal way to run it in at the time by not having to over rev it or have it labour. I'd read about varying the revs in the manual after the first trip, but by this time the car had already clocked up 200 miles at a steady speed. And to get back in a reasonable time I also had to motorway it and varying the speed was not always practical.

Had the dealer told me this before we'd driven off I would have known to opt for a totally different journey! So now for the rest of the car's life I'm going to wonder whether the piston rings haven't sealed properly, meaning less power, worse fuel consumption, oil consumption and poorer longevity. It totally negates having spent my hard earned to get a new car in the first place for me :-(

Edited by VeeFource on Thursday 8th October 23:15

[HustleRussell]

Don't be silly, the differences are insignificant and immeasurable.
Enjoy your new car.

[HustleRussell]

If it makes you feel any better it almost certainly has the wrong oil in it for a break-in period anyway.

[VeeFource]

HustleRussell said:

If it makes you feel any better it almost certainly has the wrong oil in it for a break-in period anyway.

I'd have thought that would make the process of running in even more important. Ultimately I don't know how much it's effected it, which is hugely annoying in itself.

Can't believe I wasn't aware of it too just from my own reading up on cars over all those years either

[mp3manager]

VeeFource said:

Ok I'm really pi55ed off now having researched into this a great deal. We bought a new car and decided not to opt for an ex demo mainly because I could treat it well and be safe in the knowledge it's been given the best start for being long lived (I'd like to keep the car indefinitely!).

As an ex-car transporter driver, guys like me, (and the dozen or so other people who drive your new car before you go into it ), give your car absolute death. You can call it 'perks of the job'.

However if it makes you sleep better at night, you carry-on believing that your car was treated with kid-gloves and driven like Miss Daisy, before you bought it.

[VeeFource]

mp3manager said:

As an ex-car transporter driver, guys like me, (and the dozen or so other people who drive your new car before you go into it ), give your car absolute death. You can call it 'perks of the job'.

However if it makes you sleep better at night, you carry-on believing that your car was treated with kid-gloves and driven like Miss Daisy, before you bought it.

Actually I used to drive them off the ships at the docks for summer work so I know exactly how they get treated. But mine arrived with 4 miles on the clock so the piston rings still had plenty of time to bed in.

[LaurasOtherHalf]

It's all the dealers fault. Reject the car and ask for compensayshun.

[Benrad]

I work in engine development, we have two different ways of being in an engine. One with kid gloves if we need really consistent performance and emissions for development. However if it just needs a quick test then it gets put straight to max power and stays there for 10 hours. Your car will be fine, chill and enjoy it!

If it's a modern smallish turbo engine then on the motorway it's actually working pretty hard and will have been nice and hot

[VeeFource]

Benrad said:

I work in engine development, we have two different ways of being in an engine. One with kid gloves if we need really consistent performance and emissions for development. However if it just needs a quick test then it gets put straight to max power and stays there for 10 hours. Your car will be fine, chill and enjoy it!

If it's a modern smallish turbo engine then on the motorway it's actually working pretty hard and will have been nice and hot

Cheers Benrad! Your reply is the best I could have hoped for given you have the experience to actually really know what you're talking about

It's an n/a 1.6 and would have been working at about 3k rpm at 70mph so it should have been reasonable loaded. I've read engines can develop a flat spot if held at constant revs during break in but the jury's out on whether that only applied to older carbureted engines or not and also no one knows why. Either way would it not take the engine accelerating and decelerating to cause the rings to flex and spin around to round the cylinders properly?