Engine Mechanical Specifications. GMC Truck TopKick C-Series (Conventional) C4/C5 2008

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2008 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Mechanical - 7.8L 🢒 Engine Mechanical Specifications

Application	Specification
Application	Metric	English
General
Engine Type	Inline 6 Cylinder
Displacement	7.8L	476 cu in
RPO	LG4
VIN	3
Bore	115 mm	4.53 in
Stroke	125 mm	4.92 in
Compression Ratio	16.8
Engine Compression Test - Minimum	2157 kPa	313 psi
Firing Order	1-5-3-6-2-4
Block
No. 4 Crankshaft Main Bearing Clearance
Production	0.093-0.124 mm	0.0037-0.0049 in
Service Limit	0.14 mm	0.0055 in
All Other Crankshaft Main Bearing Clearances
Production	0.063-0.094 mm	0.0025-0.0037 in
Service Limit	0.14 mm	0.0055 in
Camshaft Bearing Inside Diameter	40.0-40.04 mm	1.575-1.576 in
Camshaft Journals
Production Diameter	39.950-39.975 mm	1.5728-1.5738 in
Service Limit	39.85 mm	1.569 in
Camshaft Journal to Camshaft Bearing Clearance
Production	0.025-0.070 mm	0.001-0.0028 in
Service Limit	0.15 mm	0.006 in
Camshaft Lobe Height - Exhaust	54.491 mm	2.1453 in
Camshaft Lobe Height - Intake	52.851 mm	2.0807 in
Connecting Rod Bearing Journals	72.902-72.922 mm	2.8702-2.8709 in
Crankshaft
No. 4 Crankshaft Main Bearing Journal	81.875-81.895 mm	3.2234-3.2242 in
Bearing Journal	81.845 mm	3.222 in
Other Crankshaft Main Bearings Journals	81.905-81.925 mm	3.2246-3.2254 in
Bearing Journal	81.859 mm	3.223 in
Crankshaft End Play
Production	0.040-0.205 mm	0.0016-0.0081 in
Service Limit	0.54 mm	0.0213 in
Crankshaft End Surface - Front Cover Oil Seal	8.5 mm	0.335 in
Crankshaft End Surface - Oil Seal	7.5 mm	0.295 in
Crankshaft End Surface - Oil Slinger	10.5-11.5 mm	0.413-0.453 in
Crankshaft Runout	0.45 mm	0.0177 in
Cylinder Block	0.2 mm	0.008 in
Cylinder Body Bore to Cylinder Liner Outside Diameter	0.011-0.029 mm	0.0004-0.0011 in
Cylinder Head Surface Flatness	0.2 mm	0.0078 in
Cylinder Liner Outside Diameter Specifications - 20 mm (0.79 in) Below Gasket Surface
Grade 1	117.981-117.990 mm	4.6449-4.6453 in
Grade 2	117.991-118.000 mm	4.6453-4.6457 in
Grade 3	118.001-118.010 mm	4.6457-4.64619 in
Cylinder Liner Projection	0.06-0.1 mm	0.0024-0.0039 in
Drive Gear Shaft	15.9 mm	0.626 in
Exhaust Spring
Production Specification	68.1 mm	2.6811 in
Service Limit	66.9 mm	2.6339 in
Exhaust Valves - Cylinders 1, 3 and 5	0.4 mm	0.016 in
Exhaust Valves - Cylinders 2, 4 and 6	0.4 mm	0.016 in
Exhaust Valve Guide
Production Specification	0.06-0.1 mm	0.0024-0.0039 in
Service Limit	0.25 mm	0.0098 in
Exhaust Valve Installed Depth	2.8 mm	0.110 in
Exhaust Valve - Margin Thickness	1.75 mm	0.0689 in
Gear Tooth Wall Clearance	0.3 mm	0.012 in
Hub to Idler Gear Bushing Clearance
Production	0.02-0.062 mm	0.00078-0.0024 in
Service Limit	0.2 mm	0.0079 in
Idler Gear Backlash	0.3 mm	0.012 in
Idler Gear End Play	0.2 mm	0.008 in
Intake Valve Guide
Production Specification	0.04-0.07 mm	0.0016-0.0028 in
Service Limit	0.2 mm	0.0079 in
Intake Valves - Cylinders 1, 2 and 4	0.4 mm	0.016 in
Intake Valves - Cylinders 3, 5 and 6	0.4 mm	0.016 in
Intake Valve Installed Depth	2.5 mm	0.098 in
Intake Valve - Margin Thickness	1.88 mm	0.074 in
Intake Valve Spring
Production Specification	65.9 mm	2.5945 in
Service Limit	64.8 mm	2.5512 in
Piston Assembly Into Cylinder Liner - Below Top	195 mm	7.67 in
Piston to Cylinder Liner Clearance	0.092-0.11 mm	0.0036-0.0043 in
Piston Diameter - 84.6 mm (3.33 in) Below Piston Crown
Grade A	114.920-114.929 mm	4.5244-4.5248 in
Grade B	114.930-114.939 mm	4.5248-4.5251 in
Grade C	114.940-114.949 mm	4.5252-4.5255 in
Piston Pin Bore Inside Diameter	40.004-40.012 mm	1.5750-1.5752 in
Service Limit	40.05 mm	1.577 in
Piston Pin Diameter - Piston Pin Bore	0.004-0.017 mm	0.0002-0.0007 in
Piston Pin to Piston Clearance	39.95 mm	1.5728 in
Piston Ring End Gap
First Compression Ring	0.20-0.30 mm	0.0079-0.0118 in
Service Limit	1.2 mm	0.0472 in
Second and Third Compression Rings	0.30-0.45 mm	0.0118-0.0177 in
Service Limit	1.2 mm	0.0472 in
Oil Control Ring	0.20-0.40 mm	0.079-0.0157 in
Service Limit	1.2 mm	0.0472 in
Piston Ring Groove
First Groove	0.067-0.105 mm	0.0026-0.0041 in
Service Limit	0.2 mm	0.0787 in
Second and Third Grooves	0.03-0.07 mm	0.0012-0.0020 in
Service Limit	0.15 mm	0.0059 in
Oil Control Ring	0.030-0.07 mm	0.0012-0.0028 in
Service Limit	0.15 mm	0.0059 in
Valve Bridge Studs - Final Height	37-38 mm	1.46-1.50 in
Valve Cap	0.1 mm	0.004 in
Valve Face Angle
Intake Valve	30 Degrees
Exhaust Valve	45 Degrees
Valve Guide Bores
Exhaust Seat Angle	89 Degrees
Intake Seat Angle	119 Degrees
Valve Guide to Cylinder Head Surface	19 mm	0.7480 in
Valve Rocker Arm Clearance
Production	0.01-0.056 mm	0.0004-0.0022 in
Service Limit	0.2 mm	0.0079 in
Valve Rocker Arm Inside Diameter
Production	22.010-22.035 mm	0.8665-0.8675 in
Service Limit	22.15 mm	0.872 in
Valve Rocker Arm Shaft
Production Diameter	21.979-22.0 mm	0.8653-0.8661 in
Service Limit	22.85 mm	0.8602 in
Valve Seat - Installed Depth	0.65-1.1 mm	0.0255-0.0433 in
Valve Seat Thickness - Intake and Exhaust	0.5-1 mm	0.0196-0.04 in
Valve Seat Width
Intake Valve	2.5 mm	0.098 in
Exhaust Valve	2.0 mm	0.079 in
Valve Spring Tension
Specified Height - Length	46 mm	1.8110 in
Intake Production	348.1 N	78.3 lb
Service Limit	296 N	67 lb
Exhaust Production	382.5 N	86 lb
Service Limit	325 N	73 lb
Valve Stem Diameter
Intake Valve - Production Specification	7.946-7.961 mm	0.3128-0.3134 in
Service Limit	7.88 mm	0.3102 in
Exhaust Valve - Production Specification	7.921-7.936 mm	0.3118-0.3124 in
Service Limit	7.88 mm	0.3102 in