The Cummins ISF3.8 engine is a diesel, four-stroke, four-cylinder, in-line, sixteen-valve, liquid-cooled, turbocharged engine.
The engine is equipped with an electronic fuel supply system.
Figure 1 shows the ISF3.8 CM2220, ISF3.8 CM2220 AN, ISF3.8 CM2220 LAN engines with a closed crankcase ventilation system — front view.
Figure 2 shows the ISF3.8 CM2220, ISF3.8 CM2220 AN, ISF3.8 CM2220 LAN engines — left-hand view.
Figure 3 shows the ISF3.8 CM2220, ISF3.8 CM2220 AN, ISF3.8 CM2220 LAN engines with an open crankcase ventilation system — front view.
Figure 4 shows the ISF3.8 CM2220, ISF3.8 CM2220 AN, ISF3.8 CM2220 LAN engines — rear view.
Figure 5 shows the ISF3.8 CM2220, ISF3.8 CM2220 AN, ISF3.8 CM2220 LAN engines — right-hand view.
Figure 6 shows the ISF3.8 CM2220, ISF3.8 CM2220 AN, ISF3.8 CM2220 LAN engines — top view.
Engine technical specifications
Note: the power and torque values given are approximate and may vary significantly depending on the specific model, gearbox, year of manufacture, ECU software version and measurement method.
The cylinder block is made of grey cast iron.
The cylinders are bored directly in the block.
Coolant passages are bored between the cylinders.
The cylinder block has bosses and holes for mounting parts and assemblies.
Five main bearing supports are machined in the lower part of the cylinder block.
The main bearing caps are secured to the block with two bolts each.
The caps are machined together with the block and must not be interchanged.
The fourth bearing cap is machined to accept flanged bearings that limit the axial movement of the crankshaft.
Each cap has a serial number stamped on it.
The oil pump is attached to the front face of the block.
The oil pump body is made of aluminium alloy.
The crankshaft front oil seal is pressed into the oil pump body.
The flywheel housing is attached to the rear face of the block, and the clutch housing is attached to it.
The flywheel housing is made of cast iron, and the clutch housing of aluminium alloy.
The cylinder head is attached to the top of the block, and the plastic oil sump is attached to the bottom.
The cylinder head is made of grey cast iron using a cross-flow scavenging design.
A metal-reinforced, non-shrinking gasket is fitted between the cylinder block and the cylinder head.
Heat-resistant steel intake and exhaust valves are fitted in the cylinder head.
The valve stems are chrome-plated.
Each valve has one spring and is secured through a retainer by two collets.
The springs are made of transformer steel.
The valve guides are machined directly in the cylinder head and have no bushes; therefore, if the valve guides wear, the cylinder head is replaced.
The camshaft is made of cast iron and has five journals and two cams per cylinder.
The camshaft is mounted in the cylinder block.
The camshaft is driven through a gear that meshes with the crankshaft gear (Fig. 7).
The camshaft cams act on the tappets.
The tappet pushrods operate the valves through the rocker arms.
The valve rocker arms are bolted to the cylinder head.
The valve train clearances are adjusted using bolts screwed into the rocker arm, with lock nuts.
The combustion chambers are not in the lower part of the cylinder head, as they are machined in the piston crowns.
The cylinder head is closed on top by a plastic cover.
The valve seats are press-fitted into the cylinder head.
The crankshaft is made of steel, five-bearing, and rotates in main bearings fitted with thin-walled steel shells with an anti-friction layer.
The lower shells are bi-metal, and the upper ones tri-metal.
Oil drain holes are present only in the upper shells.
A hexagon is machined on the crankshaft front nose to drive the oil pump.
A gear is machined on the crankshaft rear nose to drive the fuel pump and the camshaft.
The axial movement of the crankshaft is limited by the flanges of the upper shell of the fourth main bearing.
The groove on the rear camshaft journal is machined to accommodate a thrust plate to secure the shaft against axial movement.
A shank with an internal thread is machined at the rear end of the camshaft for mounting its drive sprocket.
The camshaft rotates by means of a gear that meshes with the crankshaft gear.
The entire valve train is assembled in the timing gear housing.
The pistons are made of aluminium alloy.
The combustion chamber is machined in the piston crowns.
To install the piston correctly in the cylinder, an arrow is marked on the top surface.
The piston is installed so that the arrow faces the front of the engine.
Three rings are fitted to the pistons: two compression rings and one oil control ring.
The top ring is trapezoidal in shape.
The second compression ring has a groove. The ring must be installed with this groove facing downwards.
The oil control ring consists of a cast ring and an expander.
The piston is connected to the connecting rod by a floating piston pin.
The pin is retained against axial movement by circlips in the piston bosses.
To cool the pistons, nozzles connected to the oil gallery are installed in the lower part of the cylinder block.
Oil from the nozzles is sprayed onto the piston skirts.
The connecting rods are made of forged steel.
A tin bronze bush is pressed into the upper connecting rod eye.
The connecting rod cap is secured with two bolts.
The cylinder numbers are stamped on the connecting rod caps. The caps and the connecting rods are machined as one piece and must not be interchanged. Connecting rod bearings are inserted into the lower connecting rod eye.
The flywheel is made of cast iron, with a steel ring gear. It is attached to the crankshaft with eight bolts.
The gearbox input shaft support bearing is pressed into its central part.
The engine lubrication system is combined: the most heavily loaded parts are lubricated under pressure, and the rest either by directed splashing or by splashing of oil flowing from the clearances between mating parts.
The pressure in the lubrication system is created by the oil pump, installed in the front cover of the cylinder block and driven from the front end of the crankshaft.
The pump draws oil from the engine oil sump through the oil strainer and delivers it through the oil filter to the main oil gallery.
Oil supply passages branch off from the main gallery to the crankshaft main bearings.
Nozzles are installed in the main bearing saddles, through which oil is sprayed onto the cylinder walls and piston crowns.
Oil is supplied to the connecting rod bearings through passages machined in the crankshaft body.
An oil supply passage branches off from the main oil gallery to the camshaft bearings.
Part of the oil is diverted through a hose to the turbocharger and then returned to the sump.
Excess oil drains from the cylinder head to the oil sump through drain passages.
The above materials describe the design and technical specifications of the Cummins ISF3.8 engines (CM2220, CM2220 AN, CM2220 LAN): general layout, cylinder block, cylinder head, valve train, crankshaft, pistons, connecting rods, flywheel and lubrication system. The material is intended for studying the design, diagnostics and repair of the engine.
