Break In Period for Rebuilt Engine

[dock98]

Originally Posted by dirtysouth

What??? Now we're gonna be held accountable for our actions?

since when?

[sho305]

Most things are machined so well these days there is little break in except for cams and that kind of thing. Back in the 90s we built 500hp BBCs for boats and ran them 20 min for the new cam, then held them WOT for ten minutes or more at a time racing people or running the big lake. Had one come apart but something broke in it and got shavings in the oil, took out the bearings...then did it again. Third time was a charm, it just lost oil pressure each time. The identical twin to it never had a problem. It did take a while to get out to the lakes we ran, plus we would do a shake down/tune up run before we hammered it hard so it had a few hours on it. I always take it easy on a new motor, meaning I dont stand on it hard for long at all and try to keep the top rpm limited for a little while. On the other hand at 10hp it is not like these are stressed engines likely it does not matter. Might take a little to get the rings seated and that is about it. When I did lawn engines I went right out and mowed at top rpm all day on a fresh one, they were kohlers.