Manley Piston Ring Installation and Gap Info
Disclaimer: These are general gapping recommendations and are not to be considered absolute. State of engine tune, operating environment and personal experience must also be considered. These are all suggestions from Manley themselves
1. File fi t ring sets require filing of the top and 2nd rings to achieve the correct end gap. To properly measure the ring gap, the ring should be square in the bore 1” down from the deck. Measure the ring end gap with a feeler gauge or equivalent device. Calculate the recommended ring end gap from the chart above. (Bore size measured in inches)
2. A proper ring gap filing tool must be used. Ring filing should be done in an inward direction and square to the sides of the ring. Must de-burr all edges after filing.
3. Correct ring installation is critical. The top ring will have a shiny gray edge. When the top and 2nd ring has a dot, install dot side up. Unmarked top rings with an inner bevel install with bevel up. Unmarked 2nd rings with inner bevel install with bevel down. Narrow rings (1.0/1.2mm) that aren’t marked or beveled can be installed with either side up. Do not overlap the ends of the oil ring expander. See orientation diagram.
4. Ring to piston groove back clearance should be a minimum of .005” deeper than the radial wall dimension of the piston ring. The piston ring should not stick out of the groove by any amount. Ring groove side clearance should be a minimum of .0015” to a maximum of .0030”.
5. When included, the oil rail supports (Groove Lock Spacer) are installed on the bottom of the oil ring groove underneath the oil rail. These “RTD” oil rail supports incorporate our “Radial Tension Design”. We machine a receiver groove in the piston specifically for proper installation and fitment of these “RTD” oil rail supports. The “RTD” feature prevents rotation; thus eliminating the need for dimpled oil rail.
Ring Seating
When first starting your engine to ensure proper ring seating, do not allow the engine to idle for long periods at a time. It is a good idea to mildly load the engine as soon as you can. Highway driving is a good way to properly seat the rings quickly. Do not idle the engine as idling does not break in any engine. Manley DOES NOT recommend the use of synthetic oils during break-in. After 2000-3000 miles on the street, or one night racing on the track, the rings should be adequately seated so that any oil you prefer can then be used
Engine Preparation - Iron Cylinders
Finish hone cylinder walls with torque plates installed if available. Recommended hone grit specification: moly-face or cast iron top ring 280-320 grit. Chrome face top ring: 220-280 grit. Finished hone with a 22-24 degree cross-hatch pattern off horizontal axis, resulting in a 44-46 degree included angle. For factory OEM honed blocks, we recommend a flex hone with 240-320 grit. This won’t alter bore size and creates a better surface finish for performance ring sets.