TM 5-2420-230-24-2
B3.9 and B5.9 Series Engines
Crankcase Blowby, Measure (014-010)
Section 14 - Engine Testing - Group 14
Page 14-27
Crankcase Blowby, Measure (014-010)
Measure (014-010-010)
Refer to the table below for 4B engines' blowby** at given speed at 100-percent load.
Rated Speed
New L/min
Worn L/min
4B @ 2200
18
36
4B @ 2500
20
40
4B @ 2800
23
46
4BT @ 2200
45
90
4BT @ 2500
51
102
4BT @ 2800
57
114
** Blowby checking tool, Cummins Part No. 3822476, has a special 5.613-mm [0.221-in] orfice that must be used to
get an accurate reading.
Refer to the table below for 6B engines' blowby** at given speed at 100-percent load.
Rated Speed
New L/min
Worn L/min
6B @ 2200
26
52
6B @ 2500
30
60
6B @ 2800
34
68
6BT @ 2200
63
126
6BT @ 2500
76
152
6BT @ 2800
85
170
** Blowby checking tool, Cummins Part No. 3822476, has a special 5.613-mm [0.221-in] orifice that must be used to
get an accurate reading.
Blowby conversion chart 5.613-mm [0.221-in] orifice.
Inches of Water
Liters/Minute
Inches of Water
Liters/Minute
1
27
19
121
2
40
20
124
3
58
22
131
5
64
23
135
6
71
24
137
7
76
25
140
8
81
26
144
9
86
27
147
10
90
28
150
11
94
29
154
12
98
30
157
13
102
31
160
14
105
32
163
15
109
33
166
16
112
34
169
17
115
35
172
18
118
L-1325