Bit controversial this - what do we reckon?? Engine.

[salty_monk]

Running in an engine - hard way or the easy way...

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

[rayofleamington]

The tolerances used on modern engines make most of the difference.
If the bore roundness is very close to perfect to start with then the ring makes a full diameter contact, and rough honing is not required. Fine honing creates less frictional heat on the rings so there is very little risk of seizing, compared to how things were in the old days.
Therefore his comments on new engines sound very plausible, but when it comes to moggy engines I'll still do it the old fashioned way. The last one I fully rebuilt generated a LOT of heat in the first 150 miles (roasting heater in late December) but after it had run in I needed my coat on again.

On the Porsche I ran it normally and not light. The engine was already well used before I got it as it had been through a dyno etc.. and the bored had no honing to bed in the rings as they have a special coating which can't be honed.

[Willie]

He is talking about MODERN engines and my Daewoo was used
to the full from new and needs no oil between services and performs very well, but there is no way I would treat a reconned Minor engine
like that!

[salty_monk]

Hmmm all makes sense.. Was thinking more about a re-conditioned 2ltr Pinto that's only 1987... so I guess I'll probably just give it beans from the off then!!

[Cam]

The two schools of thought seem to originate from two different perspectives. Those who want useable power NOW!!! (Racers etc), and the ones who want long term reliability.

I have heard a lot about the abuse method and it does work, but you need to rebuild the engine in about half the time (makes sense I suppose). The Mini racers (some of them) used this method but their engines were usually stripped well before about 20-30,000 miles anyway so it did not matter.

If you want a good reliable engine for commuting etc, then run it in the proper way, not the fast way. If you want power NOW!!! and don't mind a rebuild soon then thrash it!

I ues to know of a Mini racer from Macclesfield who used to thrash his freshly rebuilt engine to Anglesey and back to run it in. But he used to regularly blow his engines up and always be rebuilding one!!

[salty_monk]

Hmmm thrash it... don't thrash it - Maybe I should "semi" thrash it!!

No seriously what do you reckon would be a suitable run-in?? 500 miles at under 4,000 rpm, change the oil & gradually increase them before giving it real beans at 1,000 miles or so after another oil change??

[Cam]

I have run a few engines in and the method I used was (is):

Use mineral oil. Run under 3000 RPM, not using WOT (Wide Open Throttle) and not labouring the engine for 500 miles.

Change the oil for more mineral oil. Change the oil filter. Run under 3000 RPM, don't labour the engine but apply WOT every now and then. Run for a further 500 miles (1000 total).

Change oil for a decent type and a new filter (engine is now basically run in), gradually increase the rev limit at about 500 RPM per 500 miles.

Everyone has different ideas about which is the best method but this has worked for me.

[MorrisMartin]

If you dont want the hastle of driving slowly for ages then hire out a dino for the day and run it in there. Expensive but quick.

[Cam]

Hmmm............. on a dyno at 3000 RPM it would take about 21 hours of constant running to cover equivalent to 1000 miles. Expensive to say the least and I'm not sure running it so high would be healthy. Maybe if you averaged half the revs? Then it would take about 42 hours.

Probably best (easier and cheaper) to run it in on the road!

[Kevin]

Probably best (easier and cheaper) to run it in on the road!

And you get to drive the car as well that way