Originally Posted by kannibul

I think the article as written (and others that recommend break-in by varying engine speed) are taking into account the pressures being applied to the rings, pistons, cylinder walls and valves.

Cars typically "burn" oil due to bad valve seals - ie, oil drops down into the combusion chamber (or out the exhaust). If you have bad rings, you don't burn oil, you lose compression. There's no a whole lot you can do at break in to prevent your rings from failing and/or wearing out. It's part of the lifecycle of the engine. Same in a sense with valve stem seals - eventually they can wear out.

Whether you vary your engine speed or not during break-in makes zero difference to the part. It has a limited number of cycles it can sustain before degradation, provided there is adequate lubrication.


One other thing, redline is a number. Case and point - same engine, same internals, and the Nizmo has a higher redline. "staying away from redline" is a load of BS. It makes no real difference to the engine how fast you run it, the same parts are moving, just faster. Sure there are physical loads that are different, however, those loads are "within spec" - it's like saying that a part won't surive because you hit redline, or that you will drastically reduce the longevity of your engine because you bounced the needle when the car only had 200 miles on it...

My uncle used to drag race one of his old cars and would wind the engine up to 12K - this car was bone stock, I think it was a mustang, but I'd have to check. He did that until he blew the flywheel out of it, which was a significant number of races later.