Cylinder Honing Question

[Johnstra]

I've never seen freshly honed cylinders until the other day when I had a 4 cylinder Toyota diesel block bored and honed. The hone job looks good except I was pretty upset to find scratch marks in each bore. It looks like the hone operator let the stones stop turning and then pulled the hone out leaving 4 sets of vertical scratches in each cylinder. They aren't deep, but I can feel them against the hone marks. This seems like a screw up to me.



The guy that runs the shop says every engine they hone looks that way and that it won't hurt a thing.



Who's right? Me or him?



-john

 

[TFucili]

At the machine shop I used to hang around at, the hone would be stroked up on the last stroke, stopped, and the tension would be taken off of the stones before removal. We would not just stop the head and pull it vertically up with the stones cutting their way along. The unit had a load meter on the back of it that showed how much load/drag was applied to the hone motor as you turned the tension wheel on the head. IIRC, the fixture was made by Sioux or Axe, but it ran Sunnen heads and stones.

 

[Johnstra]

Yeah, that's the way I understood it was supposed to work too. I don't see how the vertical scratches won't cause problems with the new rings. Crap! These guys seemed to be very good too. I'll go have a talk with them and see if they're willing to fix it.

-john

 

[JLEONARD]

From the description I would agree that although it's not textbook, the scratches should not hurt anything.

But I would still take it back and try toget them to fix it... it should only take them a couple of minutes.

 

[Johnstra]

It's a long drive for me back to the shop so I just hit each cylinder 10 strokes with a flex hone. It took all the vertical scratches out. Cross hatching looks perfect now and I feel better.

-john

 

[Ncostello]

In my opinion... those absolutely have to be taken out. As you did. If it didn't matter... they wouldn't bother honing in a crosshatch pattern in the first place. I'd be worried it would be a direct path for oil past the rings.



Its just one of those things. In honing cylinders... its either right. Or its wrong.