im just curious as I havent torn into my motor yet, although been researching parts. Seems that there is a sizing for moly piston rings of only standard, .020, and .030. what seems like a reason there would not be a .010 size manufactured.

 

Imagine your cylinders having the shape of an oak whiskey barrel. The top and bottom of each cylinder is smaller diameter than the center of the cylinder.

Most times, an engine with many miles on it would need to bore it at least .020" to get the taper/barrel shape out of the cylinders. Boring it only .010" might leave some of the cylinders tapered/barrel shaped.

 

thanks Larry, ive heard of some people just honing the walls and throwing in .010s if theyre selling the truck. i cant go that route, this truck is a keeper

 

A lot depends on the hours or miles on an engine as to what is really needed for a rebuild. If low miles, then a hone and stock rings. If high engine hours or high mileage, I would consider boring to the smaller overbore size that would clean up any barrel or tape in the cylinder walls.

I have never heard anyone putting .010" over rings in a standard bore cylinder. The end gaps of the rings would meet. If they meet, you might break a ring or ring land (aluminum between the ring grooves) on the piston once the engine reaches operating temps.

If they went with .010" over size rings, the end gaps need to be filed. Most of your high performance engine rebuilds, the builder uses .005" oversize rings and then files the end gap of the compression rings.

 

this one here has almost 200k, and with excessive blow by , surely the previouos owner neglecred it, as well as worked it hard. This oughta be interesting......

 

Now days, very few rebuild, they buy a rebuilt engine, long block or a short block.

 

i rebuilt one a few years ago for a few hundred $ and it was pretty easy . Wish I could find a source for ARP
head studs that isnt as expensive as $500 .

 

I would just wait until you get it apart and can measure your cylinder taper. If you have blowby and 200K miles, I don't think you're going to have to worry about finding .010" over rings. Hopefully they'll all clean up at .030" over.

I'd wait until you get your block back from being bored and honed, then measure what you have, and THEN order pistons and rings. You can always have custom pistons made, and order custom rings, but going with a "standard" oversize (like .030"), you can usually find something off the shelf and save a few $.

 

I do not recall any 6.7 guys saying anything about needing head studs. I am not aware of the guys "bullet proofing" the 6.7 like the 6.0/6.4.

 

was talking arp head studs for the 7.3 motor, the factory studs can stretch and a new set us about $75