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HOMESERVICE MANUALSJEEP2010WRANGLER XREPAIR AND DIAGNOSISENGINE MECHANICALMECHANICAL3.8L ENGINE (SERVICE INFORMATION)SPECIFICATIONSBLOCK SPECIFICATIONS

2010 Jeep Wrangler X

Block Specifications

2010 Jeep Wrangler XSECTION Block Specifications

GENERAL DESCRIPTION

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Engine Type	60° V-6 Engine
Number of Cylinders	6
Displacement 3.8L	3.8 Liters	231 cu. in.
Bore 3.8L	96.0 mm	3.779 cu.in.
Stroke	87 mm	3.425 in.
Compression Ratio 3.8L	-	9.6:1
Firing Order	-	1-2-3-4-5-6
Compression Pressure-Minimum	689.5 kPa	100 psi.
Cylinder Compression (Max. Difference Between Cylinders	-	25%

CYLINDER BLOCK

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Cylinder Bore Diameter (Standard) 3.8L	95.993-96.007 mm	3.7792-3.780 in.
Out of Round (Service Limits)	0.076 mm	0.003 in.
Taper (Service Limits)	0.051 mm	0.002 in.
Lifter Bore Diameter (early)	22.980-23.010 mm	0.905-0.906 in.
Lifter Bore Diameter (Late)	21.42-21.45 mm	0.843-0.844 in.
Deck Surface Flatness (Max.)	0.1 mm	0.004 in.

CRANKSHAFT

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Connecting Rod Journal Diameter	57.985-58.005 mm	2.2829-2.2837 in.
Main Bearing Journal Diameter	63.987-64.013 mm	2.5192-2.5202 in.
Journal Out-of-Round (Max.)	0.005 mm	0.0002 in.
Journal Taper (Max.)	0.003 mm	0.0001 in
End Play	0.09-0.24 mm	0.0036-0.0095 in.
Wear Limit	0.381 mm	0.015 in.
Main Bearing Diametrical Clearance 1-2-3-4	0.011-0.055 mm	0.0005-0.0022 in.
Wear Limit	0.076 mm	0.003 in.

CONNECTING RODS

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Bearing Clearance	0.019-0.067 mm.	0.0007-0.0026 in.
Wear Limit	0.074 mm	0.003 in.
Side Clearance	0.135-0.405 mm	0.005-0.016 in.
Wear Limit	0.45 mm	0.017 in.

PISTONS

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Piston Diameter 3.8L-Measured 33.01 mm (1.30 in) From Piston Top	95.968-95.998 mm.	3.778-3.779 in.
Clearance in Bore @ Size Location (New)	-0.005-0.039 mm	-0.0002-0.0015 in.
Weight 3.8L	426 ± 5 grams	15.03 ± 0.1764 oz.

PISTON PINS

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Type	Press Fit in Rod (Serviced as a Assembly)
Clearance in Piston @ 21C (70°F)	0.006-0.019 mm	0.0002-0.0007 in.
Clearance in Connecting Rod	Interference Fit
Diameter	22.87-22.88 mm	0.9007-0.9009 in.
Length 3.8L	71.25-71.75 mm	2.805-2.824 in.

PISTON RINGS

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Ring End Gap
Top Compression Ring	0.20-0.36 mm	0.008-0.014 in.
Second Compression Ring	0.30-0.55 mm	0.012-0.022 in.
Oil Control (Steel Rails)	0.25-0.76 mm	0.010-0.030 in.
Wear Limit-Compression Rings	0.75 mm	0.030 in.
Wear Limit-Oil Control Steel Rails	1.88 mm	0.074 in.
Ring Side Clearance	-
Top Compression Ring 3.8L	0.030-0.069 mm	0.0012-0.0027 in.
Second Compression Ring 3.8L	0.041-0.085 mm	0.0016-0.0033 in.
Oil Ring (Steel Ring)	0.015-0.225 mm	0.0006-0.0089 in.
Side Clearance Wear Limit- Top Ring	0.10 mm	0.004 in.
Side Clearance Wear Limit-2nd Ring	0.13 mm	0.005
Radial Wall Wear Limit Oil Ring Pack	0.038 mm	0.0015
Ring Width-Top Compression Ring 3.8L	1.175-1.190 mm	0.0462-0.0468
Ring Width-2nd Compression Ring 3.8L	1.47-1.49 mm	0.0579-0.0587 in.
Ring Width-Oil Ring (Steel Rails) 3.8L	0.435-0.490 mm	0.017-0.019

CAMSHAFT

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Journal Diameter	-
#1	50.724-50.775 mm	1.997-1.999 in.
#2	50.317-50.368 mm	1.9809-1.9829 in.
#3	49.936-49.987 mm	1.9659-1.9679 in.
#4	49.530-49.581 mm	1.9499-1.9520 in.
Bearing Clearance-Diametrical	0.025-0.101 mm	0.001-0.004 in.
Bearing Clearance (Max.Allowable)	0.127 mm	0.005 in.
End Play	0.254-0.508 mm	0.010-0.020 in.
Camshaft Bearing Diameter	-
#1	50.800-50.825	1.9999-2.0009 in.
#2	50.393-50.419 mm	1.9839-1.9849 in.
#3	50.013-50.038 mm	1.9690-1.9699 in.
#4	49.606-49.632 mm	1.9529-1.954 in.
Exhaust Valve Timing	-
Closes-3.8L (ATDC)	-	18°
Opens-3.8L (BBDC)	-	46°
Duration-3.8L	-	244°
Intake Valve Timing	-
Closes-3.8L (ABDC)	-	63°
Opens-3.8L (ATDC)	-	1°
Duration-3.8L	-	242°
Valve Overlap-3.8L	-	17°

HYDRAULIC LIFTER

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Type	Hydraulic Roller
Outside Diameter (early)	22.949-22.962 mm	0.903-0.904 in.
Outside Diameter (Late)	21.387-21.405 mm	0.842-0.843 in.
Clearance in Block (early)	0.020-0.061 mm	0.0007-0.0024 in.
Clearance in Block (Late)	0.015-0.063 mm	0.0006-0.0025 in.

CYLINDER HEAD

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Gasket Thickness (Compressed)	0.65-0.75 mm	0.0026-0.0030 in.

VALVES

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Face Angle-Intake	-	45-45.5°
Face Angle-Exhaust	-	45-45.5°
Head Diameter-Intake	47.87-48.13 mm	1.88-1.89 in.
Head Diameter-Exhaust	35.37-35.63 mm	1.39-1.40 in.
Valve Lift (Zero Lash)-Intake and Exhaust-3.8L	11.0 mm	0.433 in.
Valve Length-Intake	125.84-126.6 mm	4.95-4.98 in.
Valve Length-Exhaust	127.20-127.96	5.00-5.04 in.
Valve Stem to Tip Height (valve tip to spring seat washer)-Intake	48.1-49.7 mm	1.89-1.95 in.
Valve Stem to Tip Height (valve tip to spring seat washer)-Exhaust	48.53-50.09 mm	1.91-1.97 in.

VALVE SEAT

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Angle	-	44.5-45°
Run Out (Service Limits)	0.0762 mm	0.003 in.
Width-Intake and Exhaust	1.50-2.00 mm	0.057-0.078 in.

VALVE GUIDE

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Guide Bore Diameter (Std.)	6.975-7.00 mm	0.274-0.275 in.

VALVE MARGIN

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Intake	0.825-0.973 mm	0.032-0.038 in.
Exhaust	1.565-1.713 mm	0.061-0.067 in.

VALVE STEM DIAMETER

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Intake (Standard)	6.935-6.953 mm	0.2718-0.2725 in.
Exhaust (Standard)	6.906-6.924 mm	0.2718-0.2725 in.

VALVE STEM TO GUIDE CLEARANCE

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Intake	0.025-0.065 mm	0.001-0.0025 in.
Exhaust	0.059-0.094 mm	0.002-0.0037 in.
Max Allowable-Intake (Rocking Method)	0.247 mm	0.010 in.
Max Allowable-Exhaust (Rocking Method)	0.414 mm	0.016 in.

PUSH RODS

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Length	135.438 mm	5.33 in.

VALVE SPRING

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Free Length-Type A	51.1 mm	2.02 in.
Wire Diameter Type A	4.20-4.28 mm	0.15-0.19 in.
Number of Coils Type A	7.0
Spring Tension (Valve Closed) Type A	376.4-424.4 N @ 41.9 mm	84.6-95.4 lbs. @ 1.65 in.
Spring Tension (Valve Open) Type A	884.9-983.3 N @ 30.4 mm	199.0-221.0 lbs. @ 1.22 in.
Installed Height	41.1-42.7 mm	1.61-1.68 in

LUBRICATION

DESCRIPTION	SPECIFICATION
-	Metric	Standard
At Curb Idle Speed* (Minimum with engine at operating temperature)	34.47 kPa	5 psi
At 3000 RPM	205-551 kPa	30-80 psi
Oil Filter By-Pass Valve Setting	62-103 kPa	9-15 psi
Oil Pressure Switch Actuating Pressure	14-28 kPa	2-4 psi
CAUTION: *If pressure is ZERO at curb idle, DO NOT run engine at 3000 RPM.

OIL PUMP

DESCRIPTION	SPECIFICATION
-	Metric	Standard
Clearance Over rotors-Inner and Outer	0.10 mm	0.004 in.
Cover Out-Of-Flat (Max.)	0.025 mm	0.001 in.
Inner Rotor Thickness	7.64 mm	0.301 in.
Outer Rotor Thickness (Min)	7.64 mm	0.301 in.
Outer Rotor Clearance (Max)	0.039 mm	0.015 in.
Outer Rotor Diameter (Min)	79.95 mm	3.148 in.
Tip Clearance Between Rotors (Max)	0.20 mm	0.008 in.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.