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A running-in procedure for a new engine or car

Ratbag

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Jan 1, 2012
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Bayside, Melbourne, Vic
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MY06, MY10
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Forester SG & SH
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5MT/DR & 4EAT Sports
Gidday All

Modern cars and engines are made to tolerances that would have astonished even the finest car makers in the world a mere 50 years ago.

Introduction:

However, while modern bearings (etc) are brilliantly made, and like polished glass to the touch, at a nearly molecular level the surfaces are as rough as guts. There are huge "mountains" and "valleys" if examined under a microscope at around (say) 2,000x.

Running-in ("breaking-in" in US English) is the method used to smooth out these huge mountains and valleys without wrecking the engine (etc) in the process. I only wish I had some photomicrographs to demonstrate these things.

Many makers have stated that it is unnecessary to run-in a modern car. I could not disagree more. It bothers me that some people will believe this, particularly if they are younger, and not used to the essential running-in process that us old lags were brought up with!

Running-in an engine is only part of the deal. Running-in the diff/s and gearbox as well as brakes, clutch, etc are all part of the deal. Diffs are particularly hard to "work". The stuff below is based on running in a manual car. One would need to vary the procedure a bit for cars with auto transmissions, but should still be achievable with an AT. Set the AT to "Sports mode" rather than just letting it change gears whenever the load is slightly reduced.

Brakes and clutch should always be treated carefully after changing pads, machining discs, replacing clutch plate etc, at least for the first 100 kms or so.

To achieve a good run-in of the entire car, I tend to pick it up from the dealer then take it for a long drive - about 250-500 miles is good (400-800 kms). This should be on an open road (no restrictive speed limits) with little to no traffic. It should have plenty of curves, and be neither steep nor flat. The flatness is not a real problem, it's just that it is hard to vary the load properly unless the road helps you to do this. A relatively curvey road is pretty much essential, as this is what helps the diffs to bed in properly, and encourages changing gears a lot.

This is what I have done since I had my first new car, over 40 years ago:

Do NOT use cruise control ...

I tend to keep between 2500 to 4000 revs for the first 500 kms (and avoid fifth gear entirely - far too easy to let the revs drop … ) .

2500 to 4000 with the occasional short squirts to 4500 to 5000 (a couple of seconds) for the next 500 kms. Still no use of fifth. First service (oil change and filter).

2500 to 4500 revs for the next 1000 kms, with occasional squirts to 5000 lasting a couple of seconds at a time. Use fifth when cruising on a freeway, etc; but keep revs above 2500 at all times.

After the first 2000 kms, allow some use of lower revs (but don't allow engine to labour - fat chance, LOL! ) and fifth during normal suburban driving. Don't exceed 5500 revs, and then only for shortish periods. Keep this regime up until the donk has about 5000 kms on it.

Change oil and filter again at 5000 kms. Then normal servicing per usage.

This sort of run-in regime is what I would advise for "normal" use.

What this does is:

Allows the molecular level peaks and troughs on all contact surfaces to break off (if "large"). The broken off bits are removed at the first oil and filter change at around 1,000 kms.

Allows "small" molecular level peaks and troughs to flow to level.

The above will achieve an engine that has good performance and fuel economy, combined with longevity. If done carefully, the engine should not use oil; or will use a very minimal amount between normal services.

Running an engine in "slow" causes the peaks and troughs to flow completely. The peaks do not break off. This means that the engine tolerances will always be "tight". This translates into (relatively) poor fuel economy and performance; but great longevity with zero oil use.

Running an engine in "fast" causes all the molecular peaks to break off. The engine will always be "loose". This translates into an engine that gets great fuel economy and performance; but will use oil and not last as well as the "normal" engine.

The above thoughts are a result of careful observation of engines and running in practices of both myself and others over some 50 years.

Just a few thoughts on this subject, FWIW. Hope it helps some.

BTW, I never buy "Demonstrator" cars with a few thousand kms on the clock. These cars have had the very worst sort of running-in, if one can call it that!

Multiple drivers who do not have a clue how to drive the car, let alone any new car. After all, they won't be buying that one ...

[EDIT] I lost this post while writing it (my browser hung ... ), so had to recover it from a screen dump. The occasional strange error is due to Acrobat Pro, "re-interpreting" the screen dump using its text recognition engine. It works remarkably well when one thinks about what it is actually doing!
[end edit]
 
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Thanks, Mr T.

If you can see anything I've left out feel free to add comments :).
 
Great write up and food for thought. I must have been lucky however because the last 3 new cars I've owned - a 1997 Camry V6, a 2007 Forester XT and a 2013 Golf 90TSI, all manuals - were just driven as I normally drive everyday. But then I think I'm very kind to my cars in how I use them. I did use cruise control a lot in the running in though. At 362,000km (Camry), 248,000km (Forester) and 25,000km (Golf) none of them use any oil. I haven't added oil to any car in the last 16 years. All 9 new cars I've owned before that since 1972 started using some oil around the 100,000km mark, if not before (Corolla, Mazda Capella, Golf mk1) or in the case of a Mazda RX-3 rotary from day one. I have just put that down to better oils and better engine design and construction.
 
Rotaries always use oil as they have oil injectors to lubricate the seals. You had a RX3 from new? Jealous much :lildevil:
Yep, bought new in Sept 1972. A Flair Yellow sedan that had the 10A engine. Didn't use that much oil really and was such a smooth, exciting motor. Bloody awful handling and ride though with a very unpredictable rear end. I traded it in 14 months later on a new Celica that didn't have the lovely smooth responsive engine but used less fuel, was more comfortable and drove so much better over the rough QLD roads that I travelled on in the north & west at the time. I would really love to go back and drive that RX-3 again though.
 
Great write up RB! !
I used a very similar process to run in my new EJ25 about 7 months back. It is very important,
I went for the fast method to make the engine more loose and to be able to rev and drive freely.
I ran mine in for the first 2000km then drove as normal.

Now with 13000km on it I drive it with a few squirts here sand there, mainly changing gears between 2000 to 4000rpm.
Rarely so I rev the guts out of it and if I do its usually to only 550) rpm max!
My run in period I was returning great fuel economy but now it has somewhat gone down hill. I believe this is due to my computer and tune setup, soon to be rectified with either a full aftermarket computer or a ej25 gen 3 outback computer and harness or early SG5 computer and harness. It'd be great to gain OBD II from going to a SG 5 computer..
 
^ Thanks, Taza.

Good to see that someone still understands the necessity for running in an engine (and car).

I don't think that most people these days even understand that there is a relationship between how an engine is run in and its fuel economy, performance and longevity. People my age grew up with these things, but much knowledge seems to get lost with time. Could be the epitaph of our species "They were very good at forgetting things that they knew only too well".

I suspect that your drop in fuel economy has more to do with what you are doing with your right foot than anything else ... :poke: :lol: ...
I seem to have the same problem ... :iconwink: :biggrin: :rotfl:.

Roo2 gets the red line at least once a week in 1st and 2nd. I can't believe that it will do over 90 km/h in 2nd! Gets there bloody quickly too :lildevil:.

Glad that you seem so pleased with your transplant :ebiggrin:.
Don't tell me I was right ... :raz:.
 
Hi all,

Just to add to this...I work for a major European car brand, at national level, not for a dealer, and I agree that while for a normal consumer/driver you could probably get away with not following too strict of a procedure for normal daily driving duties, however for best performance of your car, a good running in process is needed. Our press vehicles (the cars on our fleet which go to journos and magazines for road tests and track tests etc), are all run in before they go onto the press fleet, and only by the technical team as they know how best to do it. They do at least 1000km for petrol engines and 1200km for diesel. In my experience, the engines don't really "free up" until around 2500. Then the power, smoothness and quietness of the engines really becomes apparent.

Cheers.
 
This is what I have done since I had my first new car, over 40 years ago:

Do NOT use cruise control ...

I tend to keep between 2500 to 4000 revs for the first 500 kms (and avoid fifth gear entirely - far too easy to let the revs drop … ) .

2500 to 4000 with the occasional short squirts to 4500 to 5000 (a couple of seconds) for the next 500 kms. Still no use of fifth. First service (oil change and filter).

2500 to 4500 revs for the next 1000 kms, with occasional squirts to 5000 lasting a couple of seconds at a time. Use fifth when cruising on a freeway, etc; but keep revs above 2500 at all times.

[lots snipped]

BTW, I never buy "Demonstrator" cars with a few thousand kms on the clock. These cars have had the very worst sort of running-in, if one can call it that!

Just wondering - if you always use this method on new cars, how do you know that other methods (including following the manufacturer's recommendations) don't give good results as well, given that you have not tried the methods?

BTW I don't disagree with your running in procedure - it seems quite reasonable.

When I bought my Outback from Subaru Docklands the cars used for demos were only used for demos, the dealership staff did not have personal use of them, so they only drove under demo conditions. The one I bought - a demo model - was the smoothest and nicest car of several Outbacks and Foresters I tried that day. At 185,000Km it is still smooth and nice, has very good off-idle response and uses no oil.

The 4.2 Torana I bought in the late 70's was another story - again it was a demo but had been used as the dealership runabout - it had been without doubt thrashed from new. While it had good midrange go a good Ford Laser could out-drag it up to about 60kph, but after that it would pull strongly to 150 or so. The motor was rebuilt at about 135,000 km I think. The metal mice got it eventually.
 
Gidday Grump

Just wondering - if you always use this method on new cars, how do you know that other methods (including following the manufacturer's recommendations) don't give good results as well, given that you have not tried the methods?

Because I have had quite a bit of experience with cars that have not been run in at all; also with ones that have been run in 'fast' and run in 'slow' over the last 50 years. Not my cars, other people's.

BTW I don't disagree with your running in procedure - it seems quite reasonable.

Thanks. That's why I wrote it ... :poke: :iconwink: :raz:

When I bought my Outback from Subaru Docklands the cars used for demos were only used for demos, the dealership staff did not have personal use of them, so they only drove under demo conditions. The one I bought - a demo model - was the smoothest and nicest car of several Outbacks and Foresters I tried that day. At 185,000Km it is still smooth and nice, has very good off-idle response and uses no oil.

'Accidents' do happen ...

Just that they are more likely to work out well if one understands what one is doing and what the ramifications are. See Mocky's post above yours.

The 4.2 Torana I bought in the late 70's was another story - again it was a demo but had been used as the dealership runabout - it had been without doubt thrashed from new. While it had good midrange go a good Ford Laser could out-drag it up to about 60kph, but after that it would pull strongly to 150 or so. The motor was rebuilt at about 135,000 km I think. The metal mice got it eventually.

Either situation is "bad" for a new car. However, either can also be "good" for a new car. It depends on how the car will be used, and the user's expectations of the car. I prefer the middle road precisely because it gives a good balance of fuel economy, performance, maintenance and longevity.

Serendipity plays a huge role in this. With something as expensive as a new car, I would prefer not to rely on serendipity ...

Serendipity worked for you with your Outback, and against you with the Torana ...
 
The terrible performance was a "feature" of the 253 (boat anchor) V8's :D
 
Think about the only thing I did when running in my new MY03 `way back in 2002 was vary the revs, didn`t overload motor and regularly (dealer) serviced it.
Also the first 25000 kms were with 3 passengers plus luggage on a semi circumnavigation road trip around the eastern portion of OZ.
Seemed to work as it now has about 332000 kms on original motor and uses little oil, about 1 to 2 l between routine, 12500 kms, changes although nowadays I tend to change the engine oil at 6000 km intervals. Fuel consumption, using E10, 91 (mostly) 95 and (rarely) 98 has been 8.9l/100 kms although I suspect it is consuming marginally more of late since moving to Adelaide. Possibly less highway use and more town.
 
The terrible performance was a "feature" of the 253 (boat anchor) V8's :D
Come to think of it my 4.2 Torana had about the same power as my 2.5 Outback - 120kw and 115kw respectively. The V8 was strangled by the emission control equipment of the day.
 
^ I think that the only emission control fitted in those days was PCV - Positive Crankcase Ventilation. Hard to see this having much effect on the performance of a 4.2L V8.

My father had one of the "Bathurst" road Toranas, and it certainly didn't lack for power. More like nearly uncontrollable on the road! Rotten fuel economy too.
 
I remember that [ame="https://www.youtube.com/watch?v=YJfeCyZfVD0"]"Torque" guy Wherrett[/ame] doing a segement on the woes of the 4.2 - he did something with the cam timing (advanced it one tooth on the spline that held the cam gear?), put on a 4 barrel Holley and a set of extractors - got about 180bhp and much lower fuel use. The retarded cam timing was a significant factor in the reduction in power as I recall.

Sorry about the hijack - maybe this needs to be split from here and put in a new thread? Mods?
 
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