Best way to break in a new engine?

[sjs]

One man's opinion on the best way to break in a new engine:

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

I'm inclined to think he is correct, in part due to quite a bit of anecdotal experience from my automotive youth, hanging out with a guy whose family owned an import auto dealership.

Let the debate begin.

 

[Batoutahell]

I've broken in 4 newly ringed honda engines in the past few years, 2 short blocks fresh from the factory, and 2 blocks that I ringed myself during rebuilds. I broke in the factory fresh blocks gently per Honda's instructions, and the rings held up fine. I broke in the rebuilt bottom ends by running them hard immediately after warm-up, and both engines held compression just fine.

I'm currently working on another engine rebuild, and I intend to break in the new rings hard and fast. I agree with the rationale behind the "run it hard" method of seating rings immediately. However, I have not personally noticed any benefit or detriment between the two methods. All things being equal, I'd rather enjoy the first 700 miles on a new set of rings.

 

[sjs]

He's not really suggesting that most engines will be significantly down on compression. The idea is that they won't seal quite as well leading to more heat past the rings baking oil deposits on the pistons, eventually clogging rings and increasing wear. You might only be down a percent or two in power at first and not even be aware of it in a street car, but for a race engine that can be a huge difference.

 

[collegeboy]

Yea I've seen that method before and it just seems weird to me..I'll be honest. I would find it hard to run a new engine hard, but maybe thats just me being anal. I would still do it the gentle way personally unless proven that doing it the other way works better. Even then..it would just feel weird. I'm sure yall can understand.

 

[rbirling]

I seem to remember reading that the factory used to run the cars hard right after they were built. They had problems with the engines due to that procedure, and changed it to an easier run around the test track. Here's the reference from the FAQ:

http://www.nsxprime.com/FAQ/Technical/breakin.htm

 

[Ponyboy]

There has got to be valid reasoning behind Honda's decision to keep the engine under 5000rpm and I'm not sure "that the engines didn't like it" is descriptive enough.

I'll have to go by Shigeru Uehara's place and ask him...be back in a few...:wink:

Motoman's evidence (if true) and rationale looks convincing. Still, I'd like to hear the other side of the argument. Proper engine break-in procedure opinions are all over the map. Mobil 1 states that synthetic in modern engines is fine and has a long list of sports cars that use it off of the manufacturing line. Royal Purple wants you to wait a minimum of 2,000 miles before using their oil. Ick. It's a shame that empirical information about such an important automotive topic is so difficult to find. Rather, to an enthusiast, it's difficult to know which opinion to believe...

Here's a few other opinions:

http://www.rc51.org/breakin.htm

http://www.avweb.com/news/maint/184932-1.html

http://www.stealth316.com/2-breakin.htm

http://www.cessna.org/benefits/articles/breakin.html

http://forums.noria.com/groupee/forums/a/tpc/f/616604995/m/470100848/r/3521000801

Does this topic land in the "The more I know, the more I don't know" category?

 

[Ponyboy]

Some very good links, I think:

http://www.importbuilders.com/breakinarticle.htm

http://www.honda-tech.com/zerothread?id=878397

 

[Arata]

Well I think he is full of it.
Todays Japanese motorcycle engines are so well made, you can get away with almost anything, including what he does, is it BETTER, no. I buy 2 to 4 new bikes a year and break them in on the dyno, I am usually in a hurry so they get run 100 miles and then full throttle, full loads, all the way to the rev limiter. Do they make more power, no, do they make less power, no. Do they seal better or worse then engines broken in with many miles on them, no.
Can anyone name a single engine manufacturer in the world who recommends doing it his way? No I did not think so. Guess the manufactures are just uninformed.