Tecumseh AH520 - Page 56

53
Reference Column 6 7 8 9A 9B
U.S. Metric U.S. Metric U.S. Metric U.S. Metric U.S. Metric
mm mm mm mm mm
Bore 2.093 53.162 2.093 53.162 2.093 53.162 2.093 53.162 2.093 53.162
2.094 53.188 2.094 53.188 2.094 53.188 2.094 53.188 2.094 53.188
Stroke 1.500 38.1 1.500 38.1 1.500 38.1 1.500 38.1 1.500 38.1
Cu. In. Displacement 5.20 85.2 5.20 85.2 5.20 85.2 5.20 85.2 5.20 85.2
(in
3
) (cc)
Point Gap .018 .457 .017 .432 .020 .508 .018 .457 .020 .508
Timing .100 2.54 .185 4.699 .070 1.778 .100 2.54 .085 2.159
B.T.D.C. See Note 1 See Note 2
Spark Plug Gap .030 .762 .030 .762 .030 .762 .030 .762 .030 .762
Piston Ring .006 .153 .007 .178 .006 .153 .007 .178 .006 .153
End Gap .014 .356 .017 .432 .016 .406 .017 .432 .016 .406
Piston 2.0870 53.01 2.0870 53.01 2.0870 53.01 2.0870 53.01 2.0870 53.01
Diameter 2.0880 53.035 2.0880 53.035 2.0880 53.035 2.0880 53.035 2.0880 53.035
(Top) .0975 1.664 .0655 1.664 .0655 1.664 .0655 1.664 .0655 1.664
.0985 1.689 .0665 1.689 .0665 1.689 .0665 1.689 .0665 1.689
.0955 1.638 .0645 1.638 .0645 1.638 .0645 1.638 .0645 1.638
(Bot.) .0965 1.664 .0655 1.664 .0655 1.664 .0655 1.664 .0655 1.664
Piston Ring .0925 2.35 .0615 1.562 .0615 1.562 .0615 1.562 .0615 1.562
Width .0935 2.375 .0625 1.587 .0625 1.587 .0625 1.587 .0625 1.587
Piston Pin .3750 9.525 .4997 12.692 .4997 12.692 .4997 12.692 .4997 12.692
Diameter .3751 9.528 .4999 12.697 .4999 12.697 .4999 12.697 .4999 12.697
Crank Pin Journal .6857 17.417 .5611 14.252 .8442 21.443 .6857 17.417 .8442 21.443
Diameter .6865 17.437 .5618 14.270 .8450 21.463 .6865 17.437 .8450 21.463
Crankshaft .8745 22.212 .6690 16.993 .9998 25.349 .8745 22.212 .9998 25.349
P.T.O. Side .8750 22.225 .6694 17.003 1.0003 25.408 .8750 22.225 1.0003 25.408
Main Brg. Dia.
Crankshaft Ball Bearing
Magneto Side .7495 19.037 .6690 16.993 .6691 16.995 .7495 19.037 .7498 19.045
Main Brg. Dia. .7500 19.05 .6694 17.003 .6695 17.005 .7500 19.05 .7503 19.058
See Note A
Crankshaft .003 .076 None None None None .003 .076 .003 .076
End Play .016 .406 .016 .406 .016 .406
TABLE OF SPECIFICATIONS
Piston Ring
Groove Width
.7498
.7503
NOTE 1: 642-08, 14A, 14B B.T.D.C. = .110
642-16D, 19A, 20A, 21, 22 B.T.D.C. = .078
NOTE 2: 642-24, 26, 29 B.T.D.C. = .087
NOTE A: Needle Bearing