Onan NHC Series Operator's/Service Manual And Parts Catalog page 212

DIMENSIONS AND CLEARANCES '
All clearances given at room temperature of 70 0 F .
All dimensions in inches unless otherwise specified.
Minimum ' Maximum
Valve Tappet Clearance
Intake 0.003
Exhaust .0.012*
Valve Stem in Guide - Intake 0.001 0.0025
Vaive Stem in Guide - Exhaust 0.0025 0.004
Valve Spring Length
Free Length 1.662
Compressed Length 1.375
Valve Spring Tension (lb.)
Open ; 71 79
Closed 38 42
Valve Seat Bore Diameter
Intake * 1.5645 1.5655
Exhaust 1.2510 1.2520
Valve Seat Diameter
Intake 1.569 1.570
Exhaust 1.255 1.256
Valve Stem Diameter
•"take 0.3425 0.3430
Exhaust 0.3410 0.3415
Valve Guide Diameter (I.D.) 0.344 0.346
Valve L i f t e r Diameter 0.7575 0.7480
Vaive L i f t e r Bore 0.7505 0.7515
Valve Seat Interference Width 1/32 3/64
Valve Face Angle 4 4 °
Valve Seat Angle 4 5 0
Vaive Interference Angle 1 °
Crankshaft Main Bearing 0.0025 0.0038
Crankshaft End Play 0.005 0.009
Camshaft Bearing 0.0015 0.003
Camshaft End Play 0.003 -
Camshaft L i f t 0.300
Camshaft Bearing Diameter 1.3760 1.3770
Camshaft Journal Diameter 1.3740' 1.3745
Rod Bearing (Forged Rod) 0.0005 0.0023
Connecting Rod End Play (Ductile Iron) 0.002 0.016
Timing Gear Backlash , 0.002 0.003
Oil Pump Gear Backlash 0.002 6.005
Piston to Cylinder, Strut Type (Measured below oil-controlling ring -
90 " from pin) Clearance 0.0015 0.0035
Piston Pin Diameter . . , 0.7500 0.7502
Piston Pin in Piston
T h u m b
p
u s h F i t
Piston Pin in Rod 0.0001 0.0005
Piston Ring Groove Width
T o P 1 0.0955 0.0965
T o P 2 0.0955 0.0965
T o P 3 0.1880 0.1890
902483