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#1108610 - 11/07/11 06:51 AM what grit and hone for moly rings?
70Cuda383 Offline

Registered: 10/07/03
Posts: 21241
Loc: Marysville, O-H-I-O
I'm getting ready to rebuild a small block with KB hypereutectic pistons and KB moly rings.

the rings came in a plain white box with no literature. the pistons are in the box at the machine shop getting balanced, so I don't know if there's any literature inthere with them....(I only opened the box, quickly glanced at everything then closed it up and took it to the shop for balancing)

looking online, I can find KB's page on what to set my end gaps at for their Hypereutectic pistons, which calls for a slightly larger end gap than cast/forged pistons (and I remember a SSgt who worked for me had a SBC with hypers, and his machine shop didn't set the ring gap big enough, and popped the top of his pistons off)

but I can't find anything on what grit to final hone the cylinders to. they're standard bore pistons and hte block isnt going to the machine shop, I'll be doing the hone myself.

do ALL moly rings get the same grit? I recall from reading in a book somewhere that they get finer grit than cast rings...but what is that grit? 320? that's what seems to stick out in my mind anyway, but wanted to verify.

Also, what's the best hone to use? a ball hone sized to the bore, or a 3 finger flex with the 3 flat stones that can be used for more than 1 bore size. ...does it matter, and you just pay more for the more versatile hone?

#1108611 - 11/07/11 08:23 AM Re: what grit and hone for moly rings? [Re: 70Cuda383]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 31158
Loc: Lincoln Nebraska
Yes 320 grit with the flexhone as you wouldn't want to use a 3 fingered hone unless you had a dial bore gauge and they are hard to use properly with a hand drill. Critical is following KB's piston to wall recommendations and .0065" per inch of bore on the top ring end gap and regular gap on the 2nd ring (I like .003" per inch of bore). I'm assuming reringing going from OE cast pistons to KB's? You said the shop is not miking your bores, Just make sure your P/W clearances are adequate and KB's recommendations are critical. Google the dingleberry honing procedure and check out "breakin secrets" at #1 dish soap and water clean the cyls taking plenty of time but working fast so you can thoroughly clean it and get it oiled and one cyl wet at a time so the others are not flash rusting while waiting their turn.
live every 24 hour block of time like it's your last day on earth

#1108612 - 11/07/11 09:50 AM Re: what grit and hone for moly rings? [Re: RapidRobert]
70Cuda383 Offline

Registered: 10/07/03
Posts: 21241
Loc: Marysville, O-H-I-O
Yup, re-ring and going w new pistons to bump compression and for the vale reliefs, it's gonna have Eddy heads.

I read their piston to wall instructions, it said that since the hypers don't "grow" as much as cast or forged, they can run a tighter clearance, but it also said that the skirts can handle a looser tolerance for a "race" motor as well, without getting banged up from rock/slap.


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