TM 5-3810-300-24&P-3
Specifications
1.0
ENGINE PARTS (Standard Size, New)
MINIMUM
MAXIMUM
LIMITS
Cross-Head Pistons and Rings
71N and 71T Engines
Piston crown:
Saddle-to-crown distance:
piston (18.7:1 compr. ratio) ...........................
2.7030"
2.7100"
T piston (17:1 compr. ratio)...........................
2.6730"
2.6800"
Diameter:
At top..............................................................
4.2226"
4.2256"
Below both compression rings .......................
4.2391"
4.2421"
Above and below seal ring groove.................
.8850"
3.8950"
Above and below bearing saddle...................
3.2360"
3.2370"
Compression rings:
Gap (top-fire ring)
......................................
.0230"
.0380"
.0600"
Compression rings:
Clearance-ring-to-groove:
Gap (No. 2 and 3) ......................................
.0180"
.0430"
.0600"
*Top (Keystone fire ring) ................................
.0010
.0050"
.0070"
No. 2 (rectangular section) ............................
.0100"
.0130"
.0220"
No. 3 (rectangular section) ............................
.0040"
.0070"
.0130"
Seal ring:
Gap (in skirt counterbore).....................................
.0020"
.0210"
.0270"
Clearance .............................................................
.0005"
.0030
.0040"
Piston skirt:
Diameter section)
......................................
4.2428"
4.2450
Clearance--skirt-to-liner,,,,....................................
.0045"
.0083"
.0120"
Seal ring bore
......................................
3.9200
3.9240"
3.9260"
Piston pin bore
......................................
.1.5000"
1.5030"
1.5040"
Oil control rings:
Gap (two rings in lower grooveX71N engine).......
.0080"
.0230"
.0430"
Gap (one ring in upper grooveX71N engine) .......
.0080"
.0230"
.0430"
Clearance (two rings in lower groove) ..................
.0015"
.0055"
.0080"
Clearance (one ring in upper groove)...................
.0010"
.0035"
.0060"
Connecting Rod (cross-head)
Length center-to-center of upper and lower bores.....
10.1230"
10.1260"
Piston Pins (Cross-Head Piston)
Length .........................................................................
3.6150"
3.6250."
Diameter .....................................................................
1.499."
1.5000"
1.4980"
Slipper bearing (bushing):
Thickness at center
......................................
.0870
.0880
.0860"
Clearance (edge of bushing to groove in piston)..
.0005"
.0105"
.0120"
*Measured with Keystone fire ring flush with outside diameter of piston crown.
% Diameter above and below the piston pin may be 4.2414"
Page 147
