I remember reading somewhere (have no idea where) that technically the best way to break in a new engine and to develop the most horsepower is to run the engine at the highest RPM possible. Now I am definitely not going to do this but it is a curious statement. Now correct me if I am wrong, but since engine component tolerances have become tighter and tighter wouldn't it make sense that the wear on the engine components at lower piston speed would be very much different than at a higher piston speed? Would this wear be enough to generate the engines true peak horsepower?

Just some food for thought. Now do we have any volunteers?

 

600 miles - nothing above 6000rpms - that's the general rule for this engine.

I'll probably stick to it, as I've got a 600 mile trip back from the dealership next Thursday. (at least I hope I can stay under it)

 

Actually Schatten it states in the manual 600miles and nothing above 5500 RPM.

To quote "Avoid full throttle starts and rapid acceleration. Do not exceed 5,500 RPM for the first 600 miles of operation".

I still have 300 miles to go and it is killing me.

 

ok ok ok, so I was 500rpm's off!
anyways, good luck, and wish me plenty of luck, I mean, do you really expect me to drive calmly for 600 miles straight below 5500rpms? *crossing fingers*

 

I have always heard that it is important to vary speeds and loads during break-in.

The only logic I have heard that makes sense to me is that the engine 'stretches' in different directions under different loads.

For instance in hard acceleration at high RPM, the pistons travel to a lower point (micorscopically) of their travel due to the pressure of the explosion above. Conversly, freewheeling at 9000 rpm allows the piston to travel microscopically farther up it's cylinder travel due to the lack of 'push back'.

As usual, I understand that this is a bit of alchemy, but the reason this is theoretically so important is because you don't want 'shoulders' in the cylinder liners. These shoulders theoretically develop at the limit of the piston's travel. If you just operate at one speed, you can get a shoulder that is within the travel you would get with varied speeds.

This is necessary because you need the piston to travel freely through it's range. If the rings hit these shoulders, it can limit their lives, and can make for an oil leaking possibility as they rings lean over slightly against these 'shoulders'.

Anyway... that is the rationale I've heard. Makes some sense to me. I'm sure there are many other mechanisms at work in this situation as well.

Dan