MulhollandDrive

I said: "You need to seat the rings and valves so you DO need to run the engine under some load at times"

You said: "Operating under load does nothing to help "seat" valves or rings - it's closing the throttle on a revving motor that is supposed to help."

I, and others on this board, have pointed out multiple "sources" that state that a load is necessary to seat the _rings_. I do not see that you have pointed out any "sources" that supports your point of view.

I really don't care if BMEP is the proper way to represent the idea that adequate cylinder pressure is necessary to seat the rings. Its a minor point.

I do suspect that engines are getting to the point that they do not need a break in period. If and when the manufacturer of my car no longer recommends a break in period, then I will drive it without a break in period.

daveZ insanity

iTrader: (4)

And you're all right - a "load" (which is a common term for high cylinder pressure) is necessary. But the simple process of combustion, even at idle, generates sufficient pressure in the cylinder to force the compression ring against the wall - this is a more than adequate "load". The fuel is exploding just as dramatically at 800 RPM and closed throttle as it is at redline and WOT. Remember that the cylinder pressure gets behind the compression ring (usually only the top one in high-peformance engines) and pushes it against the cylinder wall.

One reason many people including me believe that it doesn't matter much how you break in an engine is that it doesn't matter whether the outward pressure on the ring against the cylinder wall is 10 bar or 50 (which is about the range in an ICE, I think). Those tiny irregularities in the metal will be ground down or off just as effectively at either end of the range.

I'm really not just trying to be ornery - it's not minor. Because BMEP is calculated from torque (or hp) and RPM, you can have very high BMEP but very low cylinder pressure below the power band. If your power peak is at 6500 and you have a high, narrow power band, you won't generate much more cylinder pressure at 3500 than you will at idle.

I'm obviously not making this point very well, so I'll stop trying.

savvy

iTrader: (1)

hahaha awesome picture...am i reading that your only has like 118 miles on it?

Manu

118 kms actually I was nearing the end of the ring-seating cycle when I took this pic. Got the car with 17 kms on it. What a day

daveZ insanity

iTrader: (4)

The one by Richard Wagner?