TM 5-3825-226-24
BASIC BLOCK
SPECIFICATIONS AND TOLERANCES
Dimension
Standard
020" (0.51 mm)
040" (1.02 mm)
Location
Size
Oversize
Oversize
4.5000 to 4.5015 in.
4.5205 ± .0005 in.
4.5405 ± .0005 in.
Cylinder bore-finished
(114.300 to 114.338 mm)
(114.821 ± 0.013 mm)
(115.329 ± 0.013 mm)
**Allowable wear limit
4.506 in.
4.526 in.
(114.45 mm)
(114.96 mm)
Maximum wear limit
4.509 in.
4.529 in.
4.549 in.
(114.53 mm)
(115.03 mm)
(115.54 mm)
Surface finish (micro-inches)
5 to 15
5 to 15
5 to 15
Crosshatch included angle
140 to 150
138 to 150
138 to 150
4.5155 ± .001 in.
4.5355 ± .001 in.
Rough hone
(114.694 ± 0.03 mm)
(115.202 ± 0.03 mm)
4.5185 ± .0005 in.
4.5385 ± .0005 in.
Semifinish hone
(114.770 ± 0.013 mm)
(115.278 ± 0.013 mm)
.
0225 ± .0075 in.
0225 ± .0075 in.
0225 ± .0075 in.
*** Top ring gap new
(0.572 ± 0.190 mm)
(0.572 ± 0.190 mm)
(0.572 ± 0.190 mm)
. Maximum wear limit
045 in.
045 in.
045 in.
(1.14 mm)
(1.14 mm)
(1.14 mm)
**Allowable wear limit
.055 in.
055 in.
055 in.
(1.40 mm)
(1.40 mm)
(1.40 mm)
.0200 ± .0100 in.
0200 ± .0100 in.
0200 ± .0100 in.
***Oil ring gap-new
(0.508 ± 0.254 mm)
(0.508 ± 0.254 mm)
(0.508 ± 0.254 mm)
**Allowable wear limit
.038 in.
038 in.
038 in.
(0.97 mm)
(0.97 mm)
(0.97 mm)
Maximum wear limit
.045 in.
045 in.
045 in.
(1.14 mm)
(1.14 mm)
(1.14 mm)
Top ring vertical
0030 to .0055 in.
0030 to .0055 in.
0030 to .0055 in.
clearance in groove-new
(0.076 to 0.140 mm)
(0.076 to 0.140 mm)
(0.076 to 0.140 mm)
.011 in.
011 in.
011 in.
**Allowable wear limit
(0.28 mm)
(0.28 mm)
(0.28 mm)
Maximum wear limit
.014 in.
014 in.
014 in.
(0.36 mm)
(0.36 mm)
(0.36 mm)
Oil ring vertical
0010 to .0030 in.
0010 to .0030 in.
0010 to .0030 in.
clearance in groove-new
(0.025 to 0.076 mm)
(0.025 to 0.076 mm)
(0.025 to 0.076 mm)
*Allowable wear limit
.006 in.
006 in.
006 in.
(0.15 mm)
(0.15 mm)
(0.15 mm)
Maximum wear limit
.008 in.
008 in.
008 in.
(0.20 mm)
(0.20 mm)
(0.20 mm)
*Tolerance includes out-of-round, taper and any other irregularities. Take final measurements with blocks stabilized to
room temperature. Finished bore must clean up to 100%.
*"Allowable wear limit is the suggested wear limit for a general overhaul. However, additional service may be obtained
without honing the block if wear does not exceed maximum wear limits. (Cylinder bore wear is measured at the top and
bottom of ring travel.)
*'To be measured in unworn area of bore.
3-368
