To complete the Honda Accord models under consideration, two versions of 2.3 liter engines are used. The F23A5 series engine is the basic version, while the F23A1 and F23A4 series are essentially the same design, equipped with one of two variations of the valve timing adjustment device (VTEC) (see Section Removal, condition check and installation of rocker arm assembly).
The descriptions of most of the procedures under consideration are based on the assumption that the power unit remains in its regular place in the engine compartment of the car. In view of the above, if the engine has already been removed and installed on a workbench or mounting stand, many of the described steps should be omitted.
All 4-cylinder engines under consideration are equipped with a single overhead camshaft (SOHC) and controlling the functioning of 16 valves (4 for each cylinder). The engine has a compact design, the main component of which is the block and cylinder head made of lightweight aluminum alloy. The design of the unit includes two balancing shafts, the main purpose of which is to reduce the level of vibrations resulting from the reactive forces applied to the pistons and the crankshaft.
The crankshaft is seated in main bearings, the covers of which are attracted to the block by means of a common bridge. The fourth main bearing is thrust and additionally controls the axial play of the shaft.
The pistons are equipped with two compression rings and one oil scraper ring. Semi-floating piston pins are pressed into the upper ends of the connecting rods. Replaceable connecting rod bearing shells are located in the lower heads.
The engine is liquid-cooled based on a centrifugal rotary pump driven by a toothed belt. The coolant circulates through the internal galleries of the engine, washing the cylinders and combustion chambers, and also runs through the channels equipped in the intake piping.
Lubrication of the internal components of the engine is provided by a gear oil pump located at the front of the engine under the timing belt cover. The inner gear of the pump is driven directly from the crankshaft. Oil is drawn in through a strainer type from the oil pan, then passed through a full flow cartridge type filter mounted on the side of the power unit facing the rear bulkhead of the engine compartment.