Onan JB Service Manual

DIMENSIONS AND CLEARANCES
All clearances given at room temperature of 70°F .
All dimensions in inches unless otherwise specified .
CAMSHAFT
Bearing Journal Diameter. Front ..........................................
Bearing Journal Diameter. Rear ..........................................
Bearing Journal Diameter. Center (JC) ...................................
Bearing Clearance Limit .................................................
End Play. Camshaft ......................................................
Cam Tappet Hole Diameter (Prior to Spec P) .............................
Cam Tappet Hole Diameter (Begin Spec P) ...............................
Cam Tappet Diameter (Prior to Spec P) ...................................
Cam Tappet Diameter (Begin Spec P) ....................................
CONNECTING RODS
Large Bearing Bore Diameter ............................................
Small Bushing Bore Diameter ............................................
Distance. Center Large Bearing Bore to Small Bushing Bore ...............
Clearance. Large Bearing to Crankshaft ..................................
Piston Pin Bushing Inside Diameter (bushing reamed) .....................
CYLINDER
Cylinder Bore Honed Diameter .............................................
Maximum Allowable Taper ................................................
Maximum AI lowable Out- of - Rou nd .........................................
CRANKSHAFT
Main Bearing Journal Diameter (JB) ......................................
Main Bearing Journal Diameter (JC) ......................................
Crankshaft Main Bearing Clearance (JB) ..................................
Crankshaft Main Bearing Clearance (JC) ..................................
Connecting Rod Journal Diameter ........................................
Connecting Rod Bearing Clearance ......................................
End Play. Crankshaft ....................................................
PISTON
Piston Clearance to Cylinder Wall ........................................
PISTON PIN
length ........................................................
Diameter ................................................................
Piston Pin in Piston ......................................................
Connecting Rod Bushing Clearance .......................................
PISTON RINGS
Ring Type
Top
.................................................................
2nd .................................................................
3rd ..................................................................
Ring End Gap ...........................................................
VALVE INTAKE
Stem Diameter ..........................................................
Clearance in Guide ......................................................
Seat Angle ..............................................................
Minimum
2.500
1.1875
1.2580
. 0012
. 007
. 7505
. 8755
. 7475
. 8725
Maximum
2.505
1.1 880
1.2582
. 0037
.039
. 7515
. 8765
. 7480
. 8730
2.1871 2.1 876
1.044 1.045
5.998 6.002
. 001 .003
. 9903 . 9906
3.2495 3.2505
0.005
0.002
2.2437 2.2445
2.2427 2.2435
. 0014 . 0052
. 0024 . 0062
2.0600 2.0605
. 0010 . 0033
. 010 .015
. 0012 . 0032
2.753 2.738
. 9899 . 9901
. 0002 . 0007
Thumb Push Fit
Compression
Compression
Oil Control
. 010 .020
. 3405 . 3415
. 001 .003
. 42'
VALVE. EXHAUST (Stellite Faced)
Stem Diameter ........................................................... 3405 . 3415
Clearance in Guide ...................................................... -0030 . 0050
Seat Angle .............................................................. 45"
3
Redistribution or publication of this document, 
by any means, is strictly prohibited.

Onan JB Specifications

General

Brand	Onan
Model	JB
Category	Engine
Language	English