S&S Cycle Pistons - Manual (Page 4)

4
Failure to remove burrs may cause engine damage.
Incorrect installation of rings may result in poor performance, excessive oil consumption or engine damage.
3- For ring kits in which section #2 above does not apply, compression rings may be of plain cast iron type, chrome faced cast iron type, moly
faced cast type or chrome type.
A- The most common combinations are:
1- Two chrome faced cast rings
2- One chrome faced cast ring & one plain cast ring.
3- One moly faced cast ring & one plain cast ring.
B- Install as follows:
1- Chrome faced or moly faced ring always goes in top groove
2- Plain cast ring usually goes in second groove. Plain cast type is usually a reverse torsion ring distinguished by an inside diameter bevel
on one side of ring and a "dot" or oversize mark on other side. See Figure 1 above. If two cast iron compression rings are supplied in a
set, check to see if one is reverse torsion style ring with dot and bevel. Reverse torsion style ring always goes in second groove with dot
up if present.
C- The following rules apply to compression ring identification and placement. Rules are listed in order of priority. In other words, if both
Rule #2 and Rule #4 apply, for example, Rule #2 will be followed and Rule #4 ignored.
1- Chrome or moly ring goes in top groove.
2- Cast iron regular or reverse torsion ring goes in second groove.
3- Any identifying "pip" marks, dots or oversize marks go to top of piston.
4- Ring with one dot goes in top groove, ring with two dots goes in second groove.
5- If both rings are identical and have one dot or two dots, either ring can go in either groove.
6- If ring has dot and inside diameter bevel, dot goes to top of piston. See Figure 1above.
7- If ring has no dot but does have inside diameter bevel, bevel goes to top of piston. See Figure 2 above.
8- If ring has no dots and no bevel, it can go either way. See Figure 3 above.
4- Ring Gap Measurements
A- Compression ring end gap on big twins with 31⁄2" bore is .014" to .022".
B- End gap on all other compression rings is .016" to .024".
C- Oil ring rail end gap on big twins with 31⁄2" bore is .015" to .035".
D- Oil ring rail end gap on all others is .015" to .035".
E- Compression ring end gap on big twins with 41⁄8" bore is .017" to .025".
F- Oil ring rail end gap on big twins with 41⁄8" bore is .015" to .035".
NOTE: In certain instances, the next oversize ring set may be supplied with pistons, for example + .060" oversize rings with +.050" pistons. In this case end
gaps must be measured and rings filed as necessary. Ends must then be carefully deburred.
Failure to deburr rings may result in engine damage.
Piston Series 92-1210, 92-1550, 92-1556, and 92-1560 have a ring support rail that needs to be installed before any other rings are
installed.
CAUTION
Figure 1 Figure 2 Figure 3
CAUTION