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

has anyone actually tried this...its weird cuz its been always said to go easy on a new car...hummm what do you guys think?

 

I think that people break in their engines exactly like they want to. Some of us take it easy ans some take it hard. I'm the easy type.

 

to each his/her own

I too go easy w/ breaking in a new engine

 

Most engine builders will tell you the only thing your "breaking in" is the cam shaft.

20 minutes at 2500 RPM's with no load is all you need to break a cam in, then run that engine as hard as you like.

 

Any reliable sources to back that up? There are so many moving parts on an engine that just singling out camshafts don't make a lot of sense. What about the crank, rod bearings, rings etc? There are more forces exerted on the crank than on the cam.

 

I have tried taking it easy and running it hard on my motocross bike, and didn't notice a difference in performance either way. I have broke my bike in hard, twice last year. I got the engine put together the night before the race. I broke it in during practice and racing. The bike ran perfect. I feel nervous doing it that way though.

 

Call any engine builder and ask for yourself, the only real parts your breaking in is the cam shaft and lifters. Another rule of thumb, you never replace a cam without doing the lifters or vise-vers. Even if the engine has 50,000 miles on it, you must break in the cam shaft prior to running the motor on the street.

My brother drag races and held the fastes N/A big block Pontiac motor in the North East for 3 years. He knows what he's doing, thats how you break in a motor. He's 1/4 mile times are under 7 seconds in his rod. Takes quite a bit of knowledge of get a N/A motor to run that. Some of the org members who have come to our shop to get suspension installs have chatted with him and had the opportunity to see his work.

Pistons and rings do seat themselves, bearings never break in, they are a ware item. The only moving parts that need to be broken into each other are the camshaft and lifters. Any engine shop will tell you, 2500 RPM's with no load for 20 minutes is basically all you need to break in a new motor.

 

I somewhat agree with njmaxseltd. My dad works in an automotive machine shop and builds engines everyday. He, along with myself, do mechanic work on the side in our garage so we have a little knowledge (though I didn't talk with my dad about this, this is just from MY experience). And the biggest factor with the overhauls we do is the breaking in of the cam. The lifters usually build up and "bleed down" on their own. It's not really a big deal though, like most people make it out to be. You CAN build a motor and never really break it in and it will be fine. Although I don't recommend it.

There are other things to consider though, depending on the type of engine/parts. For instance, some rings require a long period to seat and are harder to seat. So if not broken in properly, you'll have some nice blueish smoke out your exhaust.

The breaking in process doesn't just consist of just one RPM range. Driving the vehicle easy during the first few moments of its "life" is also important.

 

There are several different "recommendation" for breaking in NEW engines. There is no simple formula or recipe. As I said before, there are other parts that have to break in besides the cam. The seating of the rings is still part of the break in. All of the moving parts of a machine are wear items depending upon how well they are maintained. Even cams and lifters develope wear patterns.