Engine Break-in

[JHZR2]

I think that the “not going over 55” rule doesn’t really apply anymore ever since overdrive transmissions became a thing a few decades ago. In the pre overdrive era you would often end up having your engine at 3000 rpm at 60mph, especially if you were running shorter gear sets like 3.73s, 4.10s etc. But these days there are cars like my Vette which has an 8 speed automatic and 2.41 gears so I can go 100 mph in 8th gear and the engine is only at 2000 rpm.

That makes sense. My 4cyl diesels are pretty high rpms on the highway.

When I was an undergraduate student in mechanical engineering (late '60s, early '70s) one of our profs told us that a hard break-in made for a better engine. Myth?

That has always been one of the theories. There is a motorcycle site that pushed that. I think what was established some time ago was that you really wanted coating down to force the rings to seat. Of course, lots of industrial engines aren’t run or operated that way with that opportunity…

What about the thousands of new rental cars that never receive any type of special break in? I've owned several ex rental cars that never had any mechanical issues that I'm sure were never "broken in".

The use profile may naturally achieve that to an extent.

Maybe. On Ferrari forums people often ask about break-in (there are specifics in the owners manuals) yet all new Ferraris arrive with anything from 30 to 80 or more miles as they are shaken down at the factory around Maranello by their test drivers. According to those that have seen them out driving, they are not babied and get hammered pretty good...so they kinda laugh at Ferrari's break-in recommendations.

I wonder how long those engines actually go before an overhaul or major service. How many actually get any practical miles at all? I saw an F40 and F50 for auction recently, super low miles. It’s not like they’re cruising the interstates….

 

[f355spider]

I wonder how long those engines actually go before an overhaul or major service. How many actually get any practical miles at all? I saw an F40 and F50 for auction recently, super low miles. It’s not like they’re cruising the interstates….

Like anything, "it depends", but there are many that accumulate a lot of miles these days. "Super cars" like the Enzo, La Ferrari, F50s, those that trade in the 7 figures are rarely driven, because they are special, and production limited to several hundred.

But, Ferrari has evolved in the past 25 years to add creature comforts and make the cars capable of being daily driven. Their cars from the 70s and 80s really weren't capable, just due to more frequent service intervals, and lack of decent AC or ergonomics. Even in the 90s, it may not have been...though I owned a 97 F355 Spider, it would have been possible. I doubt I could with my previously owned 78 308GTS or 87 328GTS.

Since around 2005 or so, Ferrari eliminated timing belts and went to chains. In 2013 they started a 7 year free maintenance program for all new cars sold. They are encouraging people to drive and enjoy the cars, and not worry about miles and maintenance.

I have friends and acquaintances with high mileage Ferraris..one has a 2013 F458 with over 135,000 miles. Others with high five figures on miles and these are all newer cars...I sold my F355 over a decade ago and it had over 60k miles at the time.

 

[Al]

If you can not do a full power run by flooring the thing in a reasonable 2+ second time (not even close to slamming it to the floor) you never willbe. One hard 10 second will not build up excessive heat. Any mechanical engineer {not limiting it to a M.W.] that knows engines will understand this.

Breaks are a whole another matter.

 

[tbm3fan]

Yes, he who is going to break in a Mercury 410 as soon as my camshaft arrives.

 

[JHZR2]

If you can not do a full power run by flooring the thing in a reasonable 2+ second time (not even close to slamming it to the floor) you never willbe. One hard 10 second will not build up excessive heat. Any mechanical engineer {not limiting it to a M.W.] that knows engines will understand this.

Breaks are a whole another matter.

I’m not sure what that actually means.

Sure, it should be able to handle it. Sure it’s not that much excess heat given the heat capacity of all the components.

For a new engine the consideration would be more along the line of asperities in sliding surfaces and in certain bearings, which could undergo different motions and alignments under hard use, which could have other effects.

In the end it’s your machine and money, and your outcome.

And it seems that nobody really knows.

But I’ve seen more OE guidance for breaking in gently than not.