SERVICE MANUAL CONNECTING RODS, PISTONS, RINGS & SLEEVES Section 5 8. Check    the    side    clearance    of    each    oil regulating ring in its respective groove. a. Refer   to   “SPECIFICATIONS”      for   proper clearance. b. On a used  piston,  it  will  probably  be  found that  the  side  clearances  tend  to  increase toward  the  top   of   the   piston   due   to   the greater  operating  temperature  prevalent  at this point. 9. Inspect  the  “windows”  of  the  oil  regulating rings for blocked oilways. NOTE:  Failure to keep the oilways clear will result in uneven lubrication of the piston and sleeve. 10.    All  rings  must  fit  loosely  in  the  piston  ring grooves without binding. 11.    Ring    bearing    surfaces    must    be    of    a smooth/satin    like    finish    with    no    burrs. Visually     inspect     new rings, prior to installation, for burrs. NOTE:    When   new   rings   are   being   installed   on   a used piston for operation  in  a  used  sleeve,  wear  on the  sleeve  may  have  left  a  ridge  where  the  piston reaches  the  top  of  its  stroke.    This  ridge  will  cause noisy engine operation and breakage of the top ring. Remedy this by removing the ridge before installing the piston ring. Clean Cylinder Sleeves as follows: 1. Using a non-caustic soap solution clean the cylinder sleeves with minimally abrasive brush. 2. Thoroughly clean the “O” ring groove in the sleeves. 3. Dry the sleeves with compressed air. 4. Clean    and    flush    out    the    water    jacket    in    the crankcase. Inspect Cylinder Sleeves as follows: 1. Measure   the   I.D.   of   the   sleeve   with   an   inside micrometer or bore gauge  from  the  top  and  bottom of the sleeve where it is subjected to piston and ring travel, and the “O” ring area. a. Take measurements at right angles to determine if   the   sleeve   is   out   of   round   or   excessively tapered. b. Maximum     permissible     diameter     sleeve wear,     at     top     of     ring     travel,     before replacement is 0.10 mm (0.004 in.). c. If  sleeve  does  not  meet  specifications,  it must  be  replaced  with  a  new  sleeve  (and piston). 2. Inspect   the   sleeve   for   SCUFFING      or SCORING.  Replace sleeve  (and  piston)  if this condition is found. NOTE:  Do not hone the cylinder sleeves. 3. Inspect Counterbore for BURRS or FRACTURES. If Sleeve Replacement is Required; 4. Identify    between    Hardened    and    Unhardened cylinder sleeves as follows: a. Make  a  solution  known  as  NITAL  by  adding  10 parts of nitric acid to 90 parts of alcohol (rubbing alcohol is satisfactory). CAUTION!  Add the nitric acid to the alcohol. Do not add alcohol to the nitric acid. b. Rub the I.D.  of the sleeve near the top or near the   bottom   with   the   Nital.      The   etched   area should extend into the sleeve approximately 1/2 inch and need be no more than 1/2 inch wide. CGES-185-3 PRINTED IN UNITED STATES OF AMERICA Page 21