Engine Break In

[dcriss]

While searching though the internet looking for topics on "Engine Break In", I came across this site:

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

I would love to know what all of you think.

I also found another (more traditional) site: http://www.aircooled.net/gnrlsite/resource/articles/engnbrkn.htm

[RichHawk]

I've seen that floating around the internet for years.
and though it does a bad of presenting a purely black and white case, I tend to agree with the Break it in with lots of power, rather than the baby it along technique.

Though I have just a handful of engines under my belt, I've done them both ways. Long ago, I babied an engine and it burned oil like crazy. I took it back out, replaced the (nearly new) rings, re-honed broke it in hard, and never used another drop of oil.

I've talked to multiple engine builders and they all say to run them in hard, But not redlining all the time: They say varied revs, and lots of WOT. They also say they can't imagine doing it without a dyno.

I've rebuilt three water cooled motorcycle engines (One with new rings in nikisil cylinders) and ran them all in hard at breakin (No Dyno). All three ran strong with no issues. Hardly conclusive I know.

Last time I had this discussion, I had a cop buddy of 20 plus years. His official opinion was that new cars that were broken in hard had noticeably more power than those that wee broken in by the factory recommended procedure.

I'll be adding in the 3.2L to my handful really soon, and am really interested in the opinion of this list.

Richard in KC

[cnavarro]

We provide links to both those web pages on break in "technique" and wholly believe in not babying a new engine.

[cstreit]

I'll third that notion. While I keep the rev's down on our new engines, I beat the pi$$ out of them to get the rings to seat. Last race engine I "babied" the rings never seated and I had to tear it down and rering it.

[MikeD930]

I agree to run the new/rebuilt engine hard up to 3/4th of redline. I used to believe in taking it easy breaking it in as per manufacture but always saw signs of blow by on the pistons during the next rebuilds. No more!