When installing new oversized pistons and rings in a D15B2 motor (NPR SWH30365ZZ) what is the appropriate cylinder bore surface finish? In an article in EngineRebuilder Larry Carley suggests the following standards:

RA 12-24
RPK 6-24
RVK 20-60
RK 25-50

I am familiar with RA but not the other standards

I have been unable to find any recommendations from the manufacturer, Nippon Piston Ring
Dennis Waller

 

This may help

http://www.redpepperracing.com....html

 

quick questions but on a low mileage engine is is mandatory to hone the liners?
i can still see the cross pattern in mine and there are no up/down scores etc.

also should the surface of the cylinder feel rough or smooth on the fingers when you run them up and down?

im guessing the speed to move the hone up/down dictates the angle of the cross pattern created by the stones right? also what rpm does a hone need to be run at?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redsolturbo &raquo;</TD></TR><TR><TD CLASS="quote">quick questions but on a low mileage engine is is mandatory to hone the liners?
i can still see the cross pattern in mine and there are no up/down scores etc.

also should the surface of the cylinder feel rough or smooth on the fingers when you run them up and down?

im guessing the speed to move the hone up/down dictates the angle of the cross pattern created by the stones right? also what rpm does a hone need to be run at?
</TD></TR></TABLE>

if you check your taper and out-of-round specs and eveything checks out okay...no, its not manditory to do so, but its a good idea to deglaze the cylinder walls(~.0002-3")

it should feel purdy smooth.

yes, how rapidly the hone moves up and down the bore determines the cross-hatch angle. as for RPM... the Quik-dway machine i used had one RPM speed: on.

hope this helps.

-Chris

 

lol thanks!

some people have said you dont want to run a hone at more than 500rpm, others say you can run them up to 3000rpm ish, i have tiny thin (but long) stones but my drill only runs at a flat 2000