The Honda Accord models under consideration are equipped with two versions of 2.3-liter engines. 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).
Most of the procedures described here are written on the assumption that the powertrain remains in its original location in the engine bay of the vehicle. As such, if the engine has already been removed and mounted on a workbench or assembly stand, many of the steps described here should be omitted.
All the 4-cylinder engines under consideration are equipped with a single overhead camshaft (SOHC) that controls the operation of 16 valves (4 for each cylinder). The engine has a compact design, the main components of which are the cylinder block and 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 arising from the reactive forces applied to the pistons and crankshaft.
The crankshaft is seated in main bearings, the caps of which are pulled to the block by means of a common bridge. The fourth main bearing is a thrust bearing and additionally controls the axial play of the shaft.
The pistons are equipped with two compression rings and one oil scraper ring. The piston pins, which have a semi-floating fit, are pressed into the upper heads of the connecting rods. The lower heads contain replaceable liners of connecting rod bearings.
The engine has liquid cooling 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 is also driven through channels equipped in the intake manifold.
Lubrication is supplied to the internal engine components by a gear oil pump located at the front of the engine under the timing belt cover. The internal gear of the pump is driven directly by the crankshaft. Oil is sucked through a mesh filter from the oil pan, then passed through a full-flow cartridge filter mounted on the side of the power unit facing the rear bulkhead.
(Based on materials from the website «HondaBook.ru»)