12000-ZZ3-405ZA Honda BLOCK ASSY., CYLINDER *NH8* (DARK GRAY)

Engine Design
Cylinder, Valve And Injection Pump LocationBore ... 137.2 mm (5.40 in)Stroke ... 152.4 mm (6.00 in)Number and Arrangement of Cylinders ... V-8Firing Order (Injection Sequence) ... 1,8,4,3,6,5,7,2Rotation of Crankshaft (when seen from flywheel end) ... counterclockwiseRotation of Fuel Pump Camshaft (when seen from pump drive end) ... counterclockwise Front end of engine is opposite to flywheel end.Left side and right side of engine are as seen from flywheel end.No. 1 cylinder is the front cylinder on the left side.No. 2 cylinder is the front cylinder on the right side.
Fuel System Schematic
(1) Fuel tank. (2) Tank shutoff valve. (3) Direct injection adapter. (4) Fuel manifolds. (5) Fuel injection pump housing. (6) Bleed orifice. (7) Fuel inlet line from secondary filters. (8) Fuel inlet line from primary filter. (9) Check valve. (10) Fuel transfer pump. (11) Secondary fuel filter. (12) Primary fuel filter. (13) Fuel priming pump. (14) Fuel transfer pump relief valve.Fuel System
There is one fuel injection pump and one fuel injection valve for each cylinder. The fuel injection pumps are located in the fuel injection pump housing. The fuel injection valves are located in direct injection adapter (3).When the engine is running, fuel is pulled from the fuel tank through the fuel supply line and primary fuel filter (12) by fuel transfer pump (10). The fuel is then pushed to secondary fuel filters (11), and into the fuel filter housing. A bleed orifice (6) in the fuel filter housing cover vents air in the system through a line back to fuel tank (1). Fuel from the fuel filter housing goes through inlet line (7) to fuel manifolds (4) in fuel injection pump housing (5). The fuel manifolds supply fuel to each fuel injection pump.Individual fuel injection lines carry fuel from the fuel injection pumps to each cylinder. One section of line connects between the fuel injection pump and an adapter on the valve cover base. Another section of line on the inside of the valve cover base connects between the adapter and the fuel injection valve in direct injection adapter (3).The fuel filters and priming pump are located in a compartment at the front of the fuel tank. The fuel transfer pump is mounted on a drive adapter on the fuel injection pump housing, and is driven by a shaft connected to the fuel injection pump camshaft. Fuel transfer pump relief valve (14) is located in the cover of the pump.Fuel priming pump (13) is used before the engine is started to put pressure in the fuel system and to vent air from the system. A check valve (9) located in the fuel transfer pump adapter housing will let fuel go around the fuel transfer pump when the priming pump is in use.There is no bleed orifice or valve installed on the fuel injection pump housing to vent air from this part of the fuel system. Air trapped in the fuel injection lines can be vented by loosening all of the fuel injection line nuts where they connect to the adapters in the valve cover base. Move the governor lever to the low idle position. Crank the engine with the starter motor until fuel without air comes from the fuel line connections. Tighten the fuel line nuts. This procedure is necessary because the fuel priming pump will not give enough pressure to push fuel through the reverse flow check valves in the fuel injection pumps of a direct injection system.
Location Of Fuel System Components
(4) Fuel manifolds. (5) Fuel injection pump housing. (7) Fuel inlet line from secondary filters. (8) Fuel inlet line from primary filter. (10) Fuel transfer pump.
Location Of Fuel System Components
(1) Fuel tank. (6) Bleed orifice in cover. (11) Secondary fuel filters. (12) Primary fuel filter. (13) Priming pump.An automatic timing advance unit is mounted on the front of the fuel injection pump camshaft. It is driven by the engine camshaft gear inside the front timing gear housing. The automatic timing advance unit gives easier starting and smooth low speed operation. It will also advance timing as engine speed increases to give correct engine operation efficiency.Fuel Injection Pump
The rotation of the lobes on the camshaft (12) cause lifters (9) and pump plungers (5) to move up and down. The stroke of each pump plunger is always the same. The force of springs (6) hold lifters (9) against the cams of the camshaft.The pump housing is a "V" shape (similiar to the engine cylinder block), with four pumps on each side.When the pump plunger is down, fuel from fuel manifold (1) goes through inlet passage (2) and fills the chamber above pump plunger (5). As the plunger moves up it closes the inlet passage.The pressure of the fuel in the chamber above the plunger increases until it is high enough to cause check valve (3) to open. Fuel under high pressure flows out of the check valve, through the fuel line to the injection valve, until the inlet passage opens into pressure relief passage (4) in the plunger. The pressure in the chamber decreases and check valve (3) closes.The longer inlet passage (2) is closed, the larger the amount of fuel which will be forced through check valve (3). The period for which the inlet passage is closed is controlled by pressure relief passage (4). The design of the passage makes it possible to change the inlet passage closed time by rotation of the plunger. When the governor moves fuel racks (8), they move gears (7) that are fastened to plungers (5). This causes a rotation of the plungers.
Cross Section Of The Fuel Injection Pump Housing
(1) Fuel manifold. (2) Inlet passage. (3) Check valve. (4) Pressure relief passage. (5) Pump plunger. (6) Spring. (7) Gear. (8) Fuel rack (left). (9) Lifter. (10) Link. (11) Lever. (12) Camshaft.The governor is connected to the left rack. The spring load on lever (11) removes the play between the racks and link (10). The fuel racks are connected by link (10). They move in opposite directions (when one rack moves