ok, here's the thing. a break in period as you would experience following the owner's manual makes no sense. after all, the engine doesn't "know" how many miles are on it, and magically experience this sudden increase in strength or reliability right at 1k miles. it happens gradually, over time, not suddenly.

it seems to me that if you gradually expose your engine to greater stresses as it is "breaking in" it more closely mimic the actual process of breaking in, that is to say, that metal-to-metal contact areas will burnish and seat properly over time. in fact, it may even break in faster.

so if you're supposed to keep in under 4krpms when the car is brand new, why don't we impliment a linear scale, with the rev limit being 4k at 0 miles, and 7k at 1k miles. we would then have the following table:

0 4000
100 4300
200 4600
300 4900
400 5200
500 5500
600 5800
700 6100
800 6400
900 6700
1000 7000

doesn't this make more sense?

now, we might want to make the scale non-linear, in that the increases in permissible rpm occur in larger jumps towards the end of the break in period, essentially sliding the scale later, but this is also easily computed.

what do you have to say?

ken

 

since nobody seems to want to bite at this issue, here's some more food for thought:

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

feedback appreciated!

ken

 

Maybe its just that engineers who designed your engine think its the safest way to break it in to avoid all sorts of hassels and detect initial problems early on without destroying the whole engine.

Break-in isn't just about making nice-nice to metal on metal. Its about being safe and cautious.

What if something is actually wrong with the construction of your engine? What if a valve isn't seated properly? What if something isn't bolted down properly? Straining that problem at 4krpm is much safer and will most likely result in less repairs than at 6krpm.

And then what about grear/transmission break-in? If not broken in properly you can lose a lot of the protection that comes with a new set of gears. Or for that matter, breaking in your suspension and chasis?

I don't know if this MotoMan guy is right or not in terms of his ideas about seals and rings and whatever breaking in... but he's obviously no engineer and his focus is very limited.

jason

 

thanks for your thoughts!

i can't say i totally agree with motoman, but on the other hand i'm still not convinced this "keep it under 4krpm for 1kmi" isn't just a wee bit arbitrary.

anyway, in my case, it doesn't matter much. i've only got 300 miles to go and a ski trip is on the books.

-ken