2.0 Liter Gasoline Engine

GENERAL INFORMATION

This section of the manual describes repair procedures for 2 L engines that are performed with the engine installed in the vehicle. If the engine has been removed from the vehicle and disassembled, all preliminary disassembly operations are omitted.

It should be noted that, although it is possible to overhaul components such as the connecting rod and piston assembly without removing the engine, this work usually cannot be performed as a separate independent operation. Repair of the crankshaft, connecting rods, and other mechanisms generally requires additional preparatory work (for example, cleaning of parts and flushing of oil passages is mandatory). For this reason, such work is included in the list of main engine overhaul procedures.

Engine Description: The 2 L engine belongs to the SR series installed on Nissan vehicles.

The engine has 16 valves, overhead camshafts, four cylinders in-line, and two camshafts. The engine is mounted transversely in the front of the vehicle. The transmission is installed on the left side of the engine.

The crankshaft has 5 main bearings. Crankshaft end play is adjusted by selecting thrust half-washers installed adjacent to the upper bearing shell of the center (3rd) main bearing.

The connecting rod bearings consist of two bearing shells installed in the connecting rod and the connecting rod cap parallel to the crankshaft axis. The connecting rods are attached to the pistons with piston pins, which are press-fitted into the connecting rod small end and secured in the piston with snap rings. The pistons are made of aluminum alloy and each piston has three rings: two compression rings and one oil control ring.

The cylinder block is made of cast iron, and the cylinders are bored inside the block. On engines of this type, the cylinder bores are sometimes called "dry sleeves".

The intake and exhaust valves are closed by coil springs and move inside valve guides pressed into the cylinder head together with the valve seats. If the seat and guide are excessively worn, they can be pressed out independently of each other and replaced with new ones.

The camshafts are driven by a chain and operate the 16 valves through rocker arms. The rocker arms are installed directly under the camshafts. Valve clearances are adjusted automatically by hydraulic lash adjusters. The lower camshaft journal bearings are the bores machined in the cylinder head bosses.

The engine lubrication system uses an oil pump driven from the front end of the crankshaft. Oil passes through the oil strainer with coarse filter and through the full-flow oil filter screwed into the cylinder block, from which it is directed through oil passages inside the cylinder block and crankcase to the crankshaft main bearings and the camshaft journals. The connecting rod bearings are lubricated under pressure through holes in the crankshaft; the camshaft journals are also lubricated under pressure. Cam lobes, valve stems, and other engine components are lubricated by splash. Some models are equipped with an oil cooler designed to maintain the oil temperature at a constant level under extreme operating conditions.