More miles on a new motor=power increase

[DMAN302]

People keep saying an engine will loosen up with added miles...how many miles does this usually take? Why does it occur? What increases are common? I just don't see how or why it happens but I've been told this a half dozen times in the last week or so and I'm curious what this is based on?

 

[mattmcdan]

It's the rings against the cylinder wall, the less friction the less resistance it has, thus easier turning.

 

[89white50]

its all the clearances between all the bearings and journals get slightly larger, therefore less friction and tis spins more easily. most bearings these days come with a coating that is suppose to wear off after a certain amount of use.

 

[5spd GT]

Yep, things are so tight in a new engine...and after some wear patterns are made and some friction of the rings against the walls, it increases the clearances (not so tight) and therefore is a bit easier to turn around...

Eventually it reaches a point where the clearances are to much (starts blow-by or piston knock) where the extra clearances hurt more than help. Lost compression is lost power...

 

[DMAN302]

Has anyone been able to verify a true gain after say 1000 or 2000 vs new?

 

[mattmcdan]

I just rebuilt mine so I will be able to be a lab rat on this topic, I will keep you guys posted (have to get a diff intake first)

 

[Roland69]

I think you should be broke in by now DMAN

 

[mackey]

You aren't going to see a night and day difference. It will be minimal. Say no more than .1 at the track IF that.

 

[5spd GT]

I gained 1.2 mph with very similar weather conditions and same shift points. I bet half of that was from the "breaking in"...

I swear I actually felt it get a bit quicker...it seemed to have a bit more "pick-up" than it used to...

Engines continue to "break-in" constantly...and eventually wear out...