[wilf leek]

Help the further education of a poor Brit if you will.

I am puzzled.

Whilst I know that the extremely fine tolerances and surface finishes achieved in modern hi-tech engines means that break in periods are pretty much a thing of the past, I still see reports here of brand new engines , BBs and SBs, being given full power and full rpm runs on the dynos at the engine builders. These are dinosaur engines - they don't benefit from the new materials and superfine finishes you get in modern engines (do they????).

My question - since my own engine builder told me to break-in my 408W stroker in the "traditional" way before giving it the full monty, and this took all of 1000 road miles before I could safely bounce it off the rev limiter, how long is an engine usually broken in on a dyno, before a full power pull is recorded?

I can't see that any engine builder could afford to run an engine for the equivalent hours of 1000 road miles, so they must be seeing max rpm and output well before that.

How so?