The Chrysler/Dodge 318 Magnum is a 5.2 l (5,211 cc, 318.0 cu.in.) natural aspirated V8 90° four-stroke gasoline engine from Chrysler LA/Magnum-family. This engine was manufactured from 1992 up to 2003.
The Chrysler 318 Magnum features a cast-iron block and two cast-iron heads with a single camshaft (OHV) and two valves per cylinder (16 valves in total). The Chrysler 3.9L Magnum engine is equipped with a multi-point fuel injection system and a mechanically timed electrical ignition system with an ignition coil and mechanical distributor.
The compression ratio rating is 9.1:1. Cylinder bore and the piston stroke are 99.3 mm (3.91 in) and 84.0 mm (3.31 in), respectively. It produces 234 PS (172 kW; 230 HP) at 4,100 rpm of horsepower and 400 N·m (40.8 kg·m, 295 ft·lb) at 3,000 rpm of maximum torque.
General information
| Engine Specifications | |
| Engine model | Chrysler 5.2 L (318 cu in) Magnum |
| Layout | Four stroke, V8 |
| Fuel type | Gasoline (petrol) |
| Production | 1992-2003 |
| Displacement | 5.2 L, 5,211 cc (318.0 cu in) |
| Fuel system | Multi-point Fuel Injection |
| Power adder | None |
| Power output | 234 PS (172 kW; 230 HP) at 4,100 rpm |
| Torque output | 400 N·m (40.8 kg·m, 295 ft·lb) at 3,000 rpm |
| Firing order | 1-8-4-3-6-5-7-2 |
| Dimensions (L x W x H): | – |
Cylinder block
The 318 Magnum engine has a cast-iron block with a five-bearings crankshaft supported system. The cylinder bore is 99.3 mm (3.91 in), piston stroke is 84.0 mm (3.31 in) and the compression ratio rating is 9.1:1. This motor has aluminum alloy pistons with two compression and one oil control rings, forged steel connecting rods, and nodular iron crankshaft. The crankshaft main journal diameter is 63.5 mm (2.5 in) and the crankpin diameter is 53.0 mm (2.08 in).
| Cylinder block | ||
| Cylinder block alloy | Cast-iron | |
| Compression ratio: | 9.1:1 | |
| Cylinder bore: | 99.3 mm (3.91 in) | |
| Piston stroke: | 84.0 mm (3.31 in) | |
| Number of piston rings (compression / oil): | 2/1 | |
| Number of main bearings: | 5 | |
| Cylinder inner diameter (standard): | 99.314-99.365 mm (3.91-3.912 in) | |
| Piston skirt diameter (standard): | – | |
| Piston pin outer diameter: | 24.996-25.001 mm (0.9841-0.9843 in) | |
| Piston ring side clearance: | Top | 0.038-0.076 mm (0.0015-0.003 in) |
| Second | 0.038-0.076 mm (0.0015-0.003 in) | |
| Oil | 0.060-0.210 mm (0.0024-0.0083 in) | |
| Piston ring end gap: | Top | 0.254-0.508 mm (0.010-0.020 in) |
| Second | 0.254-0.508 mm (0.010-0.020 in) | |
| Oil | 0.254-1.270 mm (0.010-0.050 in) | |
| Connecting rod small end diameter: | 24.940-24.978 mm (0.9819-0.9834 in) | |
| Crankshaft main journal diameter: | 63.487-63.513 mm (2.4995-2.5005 in) | |
| Crankpin diameter: | 53.950-53.975 mm (2.124-2.125 in) | |
Main bearing beam bolts tightening procedure and torque specs:
- 115 Nm; 11.5 kg·m; 85 ft·lb in two-three stages
After securing bearing cap bolts, make sure crankshaft turns smoothly by hand.
Connecting rod bearing bolts
- 61 Nm; 6.0 kg·m; 45 ft·lb
Cylinder head
The cylinder heads are made of cats-iron. The engine has a single camshaft over-head valves. The camshaft is driven by a single timing chain. The intake valve diameter is 48.665 mm (1.916 in), the duration is 250° the exhaust valve diameter is 41.250 mm (1.624 in), the duration is 264°. The Chrysler 318 Magnum engine is equipped with hydraulic valve tappets.
| Cylinder head | ||
| Block head alloy | Cast-iron | |
| Valve Arrangement: | OHV, chain drive | |
| Head surface flatness | – | |
| Valves: | 16 (2 valves per cylinder) | |
| Intake valve timing | 250° | |
| Exhaust valve timing: | 264° | |
| Valve head diameter: | INTAKE | 48.665 mm (1.9159 in) |
| EXHAUST | 41.250 mm (1.624 in) | |
| Valve length: | INTAKE | 124.280-125.92 mm (4.8929-4.9575 in) |
| EXHAUST | 124.64-125.27 mm (4.9071-4.9319 in) | |
| Valve stem diameter: | INTAKE | 7.899-7.925 mm (0.311-0.312 in) |
| EXHAUST | 7.899-7.925 mm (0.311-0.312 in) | |
| Valve spring free length: | 49.962 mm (1.967 in) | |
Head tightening procedure and torque specs:
- Step 1: 68 Nm; 6.8 kg·m; 50 ft·lb
- Step 2: 143 Nm; 14.0 kg·m; 105 ft·lb
Cylinder head cover bolts
- 11 Nm; 1.1 kg·m; 8.1 ft·lb
Maintenance data
| Compression pressure | |
| Standard | 689 kPa (100 psi) |
| Oil system | |
| Recommended engine oil | SAE: 10W-30 |
| Oil type API | API: SH or SH/CD |
| Engine oil capacity (Refill capacity) |
With filter change 4.7 L (5.0 US. qt, 4.2 Imp. qt.) Without filter change 4.3 L (4.6 US. qt, 3.8 Imp. qt.) |
| Oil pressure |
Idle speed: 41.4 kPA (6 psi) 3,000 rpm 207-551 kPA (30-80 psi) |
| Ignition system | |
| Spark plug | Champion RC12YC |
| Spark plug gap | 0.9 mm (0.0354 in) |
| Spark plug tightening torque | 41.0 N·m (4.2 kg·m, 30.2 ft·lb) |
Vehicle applications
| Model | Years Produced |
| Dodge Dakota | 1992–2000 |
| Dodge Ram | 1992–2001 |
| Dodge Durango | 1998–2000 |
| Dodge Ramcharger | 1992–1993 |
| Dodge Ram Van | 1992–2003 |
| Jeep Grand Cherokee | 1993–1998 |
Author:
SO WHEN DOES THE ENGINE FIRE AT IDLE? BFTDC, TDC OR ATDC, AND HOW MANY DEGREES? I HAVE A ’96 5.2 WHICH DOES NOT WANT TO START, FIRES BUT WONT RUN. HOOKED UP TIMING LIGHT & IT LOOKS LIKE IT IS FIRING ABOUT 15 DEG AFTER. TRYING TO DETERMINE IF IT IS TIMING CHAIN. THANKS.
The timing shouldnt have anything to do with a chain. in my 92 we hooked it up to a modis and cet the sinc of the distributor
Timing needs to occur before TDC so there is lead time for the fuel to burn and push the piston down.
Bump it to at least 5 before TDC and it should start. I believe I ran my old Dodge van at 13 Before TDC
There are two things that control when this motor fires.
1) The distributor position. Turn the dust until you. get to about 5-6deg BTDC. It should fire and try to run at least.
2) If it has a lot of miles the timing chain could have jumped which would also mess up timing.
If turning the distributor doesn’t make it run the timing chain is behind the water pump. The spec is less than 3/8 in slack in the chain.
i am thinking about buying a 1996 dodge ram that has a 318or 5.2 liter,am i in for alot of repair.i think it has 130,000 on it .
most likely not much work i have 2000 with 141k and it runs fine engine wise only problems you should have is the dash cracking or minor electical like window switches.
Do you know the factory cam specs? I am trying to replace the cam and lifters and cant seem to find the specs on this to order a new cam or upgrade slightly without having to replace the push rods and springs.
can I turbocharge my 1999 Dodge Dakota 318cc 5.2L? and how would I go about it?