182k and you can still see..

[RallyKeith]

the original cross hatching on the cylinder walls of the DOHC EJ25 I just did the head gaskets on. I was very impressed when I pulled the heads off of this motor and you could still see it. That made me feel a little better about this car considering the large amount of money I spent just to redo the top end.

 

Keith

[NoahDL88]

when i took apart an engine from my parts car, 240k on the ticker, cross hatch still visible, and every time my professor was trying to tell us all the "good" designs of a good engine, the EA-81 had every single atribute. good start for subaru.BTW at 13000 RPM the EA-81/82 has the same FPS piston speed as a chevy 350 @ 4000 RPM

[1 Lucky Texan]

So, just exactly what happens during 'break in'? It certainly doesn't seem to be anything that affects the cylinder walls. What exactly happens the the rings when the rings are 'seated'?

 

Carl

[RallyKeith]

Hadn't considered that.... I don't know. Break in is supposed to seat the rings to the cylinder walls so I guess the rings are softer and wear to match?

[cookie]

but when I was rebuilding engines and honeing them in a shop you could feel small ridges sticking up after honeing. Tearing down an engine for a failure with little mileage (new radiator hose failed) I found the edges of the rings were shiny and the cylinder walls felt more polished. I know factory engines now have excellent honing systems so the wear must be much less on initial run in.

[Setright]

Well, the hatch marks are visible and that's positive, but that doesn't mean the cylinders aren't gonna seal. The hatches won't be very deep, even though they are visible.

 

And yes, the rings have a soft nickel or similar coating to provide a sealing surface.

[All_talk]

The required "break in" has a lot to do with the rings sealing against the pistons too. And one major reason for the crosshatch is to provide a place for a small amount of oil to get trapped and lube the rings so things don't wear so fast... looks like the OEM setup is working very well.

 

Gary

[blitz]

Motors oils have gotten a lot better (and continue to do so), but IMHO, a quantum leap came when it became standard practice to press dedicated liners into aluminum castings, the benefit being the increased hardness of the liner alloy. It was pretty much impossible to get the same level of wear hardness back when the bores were cut directly into the the iron block casting.

 

During that era it was generally recognized that Mopar had the most durable iron, Ford the worst, and GM in the middle. This carried over to the head castings as well since the valve seats were cut-in directly rather than using a hardened stellite insert. Ford engines manufactured prior to '75 suffered burned valve seats through the late 70's when running "leaded" regular that contained very little lead anymore at that point.