Repair And Fix it

The Cummings 3.9-liter turbo diesel 4BT engine is a straight-4 configuration engine used in automotive applications including small trucks, SUVs and commercial vans in addition to many off-road applications that include boating, construction equipment, farm machinery and other off-road uses. Owing mainly to its ability to generate high torque at lower rpm, this Cummins workhorse engine is a favorite replacement engine for any application calling for a small diesel engine or changeover from gasoline to diesel.

General Specifications

The 4BT measures 30.6 inches long, 24.6 inches wide and 37.7 inches high. It has net of 745 to 785 lbs. without fluids or accessories, depending on configuration. The "4BT" designation means it has four cylinders and belongs to the B series of Cummins engines. The "T" stands for "turbocharged." The 4BT is a four-cylinder version of the Cummins 6BT used in Dodge trucks as a replacement for eight-cylinder gasoline engines.

Mechanical Specifications

This 3.9-liter Cummins diesel engine is an eight-valve, in-line four-cylinder engine with a displacement of 3.9 liters, or 239 cubic inches. It has a bore of 4.02 inchesand a piston stroke of 4.72 inches. With the piston at top dead center, the engine has a compression ratio of 17.5 to 1. Engine air delivery occurs via a non-intercooled turbocharger. With the oil filter, the engine holds 10 quarts of oil.

Power

As originally manufactured, this four-cylinder diesel delivered 105 horsepower at 2,300 rpm and 265 foot-lbs. of torque at 1,600 rpm. As of 2010, recent configurations deliver 130 horsepower and 335 foot-lbs. of torque. You can easily tweak the engine for more power by adjusting or changing the turbocharger, or by using different injector nozzles.

Diesel engines were once manufactured primarily as heavy-duty, internal combustion engines for use in machinery that required more power than a gasoline engine could provide. The Cummins model 555 diesel was no exception. This workhorse engine was used primarily in large pleasure boats but also had applications in heavy machinery and large, heavy-duty trucks.

General Specifications

The Cummins 555 is an eight-cylinder, four-stroke, turbo-charged diesel engine in a V formation with four cylinders on each side set at 90-degree angles to one another. This engine has a displacement of 555 cubic inches.

Power

The 555 is available in three power configurations, depending on the intended use and the number of hours per year it will be operated. There are two high-output power options and one intermittent power option. The first high-power option calls for 270 basic horsepower (BHP) at 3300 RPM. The second high-power option provides 270 BHP at 3000 RPM. The intermittent power option provides 235 BHP at 2800 RPM. Actual output is calculated at the shaft and is rated at 97 percent of BHP, but actual output depends on the accessories driven by the motor, such as alternators and other additional equipment. The high-power options are limited to full-speed operation for two hours of every six the engine is run. Intermittent operation is allowed at full power for six hours of every 12 hours of operation.

Fuel Consumption

Fuel consumption by the 555 is dependent on the power option of the engine and on the engine speed. Fuel consumption figures are based on using No. 2 diesel fuel and are given in U.S. gallons per hour. For the intermittent power rating, fuel consumption ranges from 6.9 GPH at 2200 RPM to 13 GPH at 2800 RPM. The first high-output application consumes fuel at a rate of between 8.9 GPH at 2700 RPM and 16 GPH at 3300 RPM. The fuel consumption of the second high-output power option ranges from 8.1 GPH at 2400 RPM to 15.1 GPH at 3000 RPM.

Engine Specifications

The cylinder bore is 4 5/8 inches with a piston stroke of 4 1/8 inches, allowing for a 17:1 compression ratio, and there are four valves per cylinder. Oil capacity is 6 gallons, with 5 gallons held in the oil pan and the remainder in the oil filter and tubing. The engine is water-cooled, and the configuration varies depending on the type of installation. The engine is a maximum of 63 inches long, 37 inches wide and 35 inches high.

Cummins diesel engines are a common engine option in full-size Dodge trucks. The six-cylinder, 5.9-liter Cummins engine has four valves per cylinder for a total of 24 valves. The gasket between the cylinder head and the engine block forms a tight seal between these two components. A leaking head gasket can cause the oil in the vehicle to have a milky appearance when it becomes contaminated by coolant.

Instructions

1

Place a clean container beneath the radiator, and open the drain cock with a socket wrench. Allow the coolant to drain into the pan, and save the coolant for reuse. Disconnect the cable from the negative battery terminal so you dont start the engine during the procedure.

2

Detach the accessory drive belt from its pulleys, and remove the alternator from the engine compartment with a socket wrench. Disconnect the air cleaner from the intake manifold. Remove the crankcase ventilation system and evaporative emissions system from the engine.

3

Remove the fuel lines from the fuel rail with a socket wrench. Disconnect the cables for the accelerator, cruise control and transmission to obtain access to the intake manifold. Remove the distributor cap with the electrical wiring still attached, and detach the electrical wiring from the ignition coil.

4

Detach the electrical connector from the engine coolant temperature sensor. Disconnect the water bypass hose and upper radiator hose from the engine to access the intake manifold. Remove the intake manifold and valve covers from the engine with a socket wrench.

5

Record the original position of the valve train components, including the rocker arms, push rods, exhaust manifolds and spark plugs. This ensures you can install these components in the correct position later. Remove the valve train components from the engine with a socket wrench.

6

Remove the mounting bolts for the cylinder head, and lift the cylinder heads from the engine block. Discard the gasket on the engine block.

7

Turn the crankshaft clockwise so that the timing marks for the crankshaft and camshaft do not align. This ensures that no piston is in the top dead center position when you install the cylinder head. Wait five minutes for the lash adjusters to depressurize before installing the cylinder head.

8

Place a new cylinder head gasket on the engine block, and mount the cylinder head on top of the gasket. Tighten the mounting bolts for the cylinder head to 50 foot-pounds with a torque wrench on the first pass and 105 foot-pounds on the second pass.

9

Install the valve train components to their original positions, using the notes you made in step five as a guide. Replace the additional components you removed to access the cylinder head by performing steps two through four in reverse.

10

Connect the cable for the negative battery terminal, and replace the coolant in the cooling system. Start the engine and check for fluid leaks.