Oil ring side clearance

[bbmachine]

I am assembling a stock 1997 360/5.9 Magnum with H655cp pistons, ring stack is 1.5/1.5/4.0. I measure a loose .005" side clearance on the oil ring. The specs I have found is between .001-.003". Has anybody else experienced this excessive play?

Thanks.

[mag2555]

Time call up the tech dept at that piston manufacturer and see what the call for tolerance specs and or how much the piston may expand at temp to clinch down on that .

[engineguyBill]

Yes, excessive side clearance is fairly common. The reason is that piston manufacturers use groove sizes based upon certain ring manufacturers dimensions, but replacement rings sometimes have different dimensions (usually thinner lateral widths) thereby resulting is excessive side clearance. Ask your piston manufacturer for a recommendation on whose rings to use with their pistons. All piston rings are not created equally . . . . . . . . .

[piston guy]

Several piston companies offer a "tight" oil groove option. One must be careful to not get "too tight". Careful measuring of the assembled height of the three pieces is important as that (axial) dimension varies a bit among ring manufacturers. "I" don't like to see over .005 and prefer .002-.003 max especially on metric oil rings.