Specifications - Jeep J-10 Series 1982 Technical & Service Manual

1B-26 ENGINES
Refill orBertafl
If a piston other than standard size is to be installed,
the cylinder should be bored, rather than honed, to ob
tain a true bore.
When honing to eliminate taper in the cylinder, use
full strokes. Measure cylinder at top, middle and bottom
of bore repeatedly during honing process.
When boring, always ensure the crankshaft is out of
reach of the boring cutter. Crankshaft bearings and
other internal parts must be covered or taped to protect
them during a boring or honing operation. When boring,
allow 0.001 inch (0.025 mm) to remain on the diameter
for finish honing. This will provide for the required
piston-to-cylinder clearance specifications.
NOTE: A honing or boring operation must be per
formed carefully to ensure that the specified clearance
between pistons, rings, and cylinder bores is
maintained.
By measuring the piston to be installed at the measur
ing locations and adding the mean of the clearance speci
fication, the correct finish hone cylinder dimension can
be determined. It is important that both the cylinder
and piston be measured at normal room temperature.
After honing and before the piston is inserted for fit,
each cylinder bore must be thoroughly cleaned. Use a
hot, soapy water solution and wipe dry to remove all
traces of abrasive. If all traces of abrasive are not re
moved, rapid wear of new rings and piston will result.
After washing, thoroughly oil cylinder bores.
Intermixing different size pistons has no effect on
engine balance because all pistons from standard size up
to 0.030-inch (0.762 mm) oversize weigh exactly the
same.
SPECIFICATIONS
Specifications—Four-Cylinder Engine
Typt In-Line
Bort 101.6 mm (4.00 in.)
Stroke 76.2 mm (3.0 in.)
Displacement 2.5 litre. 151 cu. in.
Compression Ratio 8.24:1
Compression Pressure, Desired 140 psi at 160 rpm
Firing Order 1,3.4. 2
Number One Cylinder Front Cylinder
Cylinder Number, Front to Rear 1,2.3,4
Cylinder Bore, Out-of-Round 0.038mm (0.0015 in. max.)
Cylinder Bore Taper . . . . 0.051mm (0.002 in.)
Cylinder Block Deck Clearance . . . 0.076mm (0.003 in.)
Cylinder Head - Flatness 0.0025-0.2032mm (0.001-0.008 in.)
Cylinder Head — Combustion Chamber Volume 52.25 cc± 0.5 cc
Piston
Piston Clearance in Bore
Top 0.0635-0.0838mm (0.0025 in.-0.0033 in.)
Bottom 0.043-0.1041 mm (0.0017 in.-0.0041 in.)
Piston Diameter 101.519-101.580mm (3.9968-3.9992 in.)
Compression Ring Side Clearance Top 0.0762mm (0.0030 in.)
Compression Ring Side Clearance
Bottom 0.0762mm (0.0030 in.)
Compression Ring Width
Top 1.9685-1.9812mm (0.077543.0780 in.)
Bottom 1.9685-1.9812mm (0.0775-0.0780 in.)
Upper Compression Ring Gap 0.25-0.56mm (0.010-0.022 in.)
Lower Compression Ring Gap 0.25-0.71 mm (0.010-0.028 in.)
Oil Ring Gap 0.381-1.397mm (0.015-0.055 in.)
Piston Pin
Diameter 23.547-23.557mm (0.92705-0.92745 in.)
Length 76.2mm (3.00 in.)
Pin to Piston
Clearance 0.003-0.013mm (0.0003-0.0005 in.)
Fit in Rod Press
Crankshaft
Main Bearing Journal
Diameter 58.39mm (2.2988 in.)
Out of Round 0.0127mm (0.0005 in. max.)
Taper 0.0127mm (0.0005 in. max.)
Clearance Limit New 0.05588mm (0.0005-0.0022 in. max.)
Crankshaft End Play New0.0889-0.2159mm (00035-0.0085 in. max.)
Rod Bearing Journal
Diameter 50.8mm (2.000 in.)
Out of Round 0.0127mm (0.0005 in. max.)
Taper 0.0127mm (0.0005 in. max.)
Clearance Limit New 0.0127-O.066O4mm (0.0005-0.0026 in.)
Rod Side Clearance 0.1492-0.4362mm (0.017 in.)
Lobe Lift
Intake .5842mm (0.230 in.)
Exhaust 5.842mm (0.230 in.)
Journal Diameter 47.4726mm (1.869 in.)
Journal Clearance 0.01778-0.0685mm (0.0007-0.0027 in.)
End Play Clearance 0.031-0.127mm (0.0015-0.1150 in.)
Cylinder Block Deck Clearance 0.076mm (0.003 in.)
Valves
Valve Train
Lash Intake and Exhaust • • • .0
Rocker Arm Ratio 1.76:1
Push Rod Length 226.746mm (8.927 in.)
Valve Timing
Intake - Opens 23° BTDC
- Closes 249° ATDC
- Duration .272°
Exhaust - Opens 246° BTDC
- Closes 27° ATDC
- Duration 572°
Maximum Lift 10.1mm (0.398 in.)
(Intake and Exhaust)
Valve Lifter
Leak-Down Rate 12 to 90 sec. with SO lb. Force
Lifter Body Diameter. . . . 21.3868-21.4046mm (0.8120-0.8427 in.)
PlungerTravel 3.175mm 0.125 inj
Clearance in Boss 0.625mm (0.0025 in.)
Lifter Bore Diameter 21.425-21.450mm (0.8435-0.8445 in J
Intake Valves
Face Angle 45°
Seat Angle 46°
Head Diameter 43.688mm (1.72 in.)
Stem Diameter 8.6995-8.68172mm (0.3425-0.3418 in.)
Overall Length 115.75mm (1.557 in.)
Stem-to-Guide Clearance. . . 0.02544).06858mm (0.001 OO.0027 in.)
Valve Seat Width 0.897-1,897mm (0.353-0.0747 in.)
Valve Installed Height
(Spring Seat to Valve Tip) 52.265mm (2.057 in.)
Valve Stem Height 50.8mm (2.00 in.)
Exhaust Valves
Face Angle 45°
Seat Angle 46°
Head Diameter 38.4mm (1.50 in.)
Stem Diameter 8.766-8.682 (3.418*3.125 in.)
Overall Length 114.02 (4.489 in.)