M42 Block Post Flex-Hone - Thoughts?

[KenC]

I just got done using a flex hone on my cylinders to prep them for the new rings.



Thoughts on the outcome?

Also, somebody was looking at the block at the house and said I was missing a ring "step" at the top of the cylinder. I wasn't sure what he was referring to. Can anyone enlighten me?

Anyhow, on to the pics...







The score right at 3 o'clock is the one that I was hoping the flex hone would clean up. I can BARELY feel it with a very gentle touch. Should I just have it honed at a machine shop now? Would I need oversized rings in that one?

[gearheadE30]

I'm not sure if the scoring as bad enough to be a problem, but since you have it all apart right now, you might as well make it as right as possible so you don't have to pull it all apart again later.

[KenC]

I don't think it was bad enough either, but I took it in anyhow.

It's at M&B in Portland.

They're going to hone and hot tank the block for me, and then install the new rings, crank bearings, rod bearings, and freeze plugs. All for $200 (plus parts obv).

I'll take pics when I get it back this week.

[boom-monkey]

Sounds like a good move taking it to the pros.

BTW, the ring step your friend is referring to is formed by the piston rings wearing away at the bore, at the top where the rings don't reach it leaves a little ridge. Not having it is a good sign, showing minimal engine wear. This is not uncommon in high mileage BMW motors from what I have witnessed.