Экспертное руководство: FAW Crankshaft And Flywheel Assembly for the CA4251P66K24T1A3E5 Tractor

Welcome to this expert guide on the FAW Crankshaft And Flywheel Assembly, the complete rotating mass at the heart of the engine for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This system is the final link in the power-generation chain.

This assembly is responsible for converting the reciprocating motion of the pistons into smooth, usable torque and delivering it to the transmission. The FAW Crankshaft And Flywheel Assembly comprises the crankshaft itself, the massive flywheel, the harmonic damper, and all associated seals, шестерни, and pulleys.

This guide is a critical resource for professional engine builders, technicians, and parts managers. We will deconstruct the entire FAW Crankshaft And Flywheel Assembly into its smallest serviceable units, from the front-most damper bolt to the rear-most pilot bearing, to ensure precision service and diagnostics.

The Flywheel Assembly (1005120-73Д) and Pilot Bearing (60305)

The ‘Flywheel Assembly’ (1005120-73Д) is the largest component in the FAW Crankshaft And Flywheel Assembly. This is a massive, heavy-duty cast iron disc. Its primary function is to store rotational energy (inertia). This inertia smooths out the violent, individual power pulses from the six cylinders, resulting in a steady rotation that is usable by the transmission.

The large-diameter face of the flywheel is also the primary friction surface for the truck’s clutch. This surface must be perfectly flat and free of heat cracks to ensure smooth clutch engagement. The ‘Flywheel Assembly’ is secured to the crankshaft flange by 12 ‘Flywheel Bolts’ (1005071-81Д). These are critical, high-strength, single-use TTY (torque-to-yield) fasteners that must be replaced any time the flywheel is removed.

Pressed into the dead center of the flywheel is the ‘First shaft front bearing’ (60305), which is commonly known as the pilot bearing. This small but vital bearing supports the end of the transmission’s input shaft, ensuring it remains perfectly centered with the FAW Crankshaft And Flywheel Assembly‘s axis of rotation. A failed pilot bearing will cause severe shifting difficulty, clutch chatter, and eventual transmission damage.

Crankshaft Sealing System: Передний (1005050-53Д) & Задний (1005060-53Д)

The FAW Crankshaft And Flywheel Assembly is sealed on both ends by two critical components. At the rear, the ‘Crankshaft Rear Oil Seal Assembly’ (1005060-53Д) is installed in the engine block *before* the flywheel is mounted. This is one of the most important seals in the engine. It is a large, cassette-style seal with a specialty dust lip and a Teflon-based main lip that prevents oil from the crankcase from leaking out and contaminating the clutch assembly. A failure here is a major repair.

At the front of the engine, behind the main pulley, is the ‘Crankshaft Front Oil Seal Assembly’ (1005050-53Д). This seal performs the same function, preventing oil from leaking out the front of the engine and contaminating the serpentine belt. Both of these seals are “wear items” and are typically replaced during any major engine overhaul to ensure the long-term reliability of the FAW Crankshaft And Flywheel Assembly.

The 12 ‘Flywheel Bolts’ (1005071-81Д) are essential for this sealing system to work. They must be tightened in a specific star pattern and to a precise torque-plus-angle specification. This ensures the flywheel is perfectly flat and “clamped” against the crank flange, which is necessary for a leak-free seal and for the proper function of the entire FAW Crankshaft And Flywheel Assembly.

Crankshaft Main Gears: Oil Pump (1005015-81Д) and Timing (1005037-81Д)

The parts list shows the ‘Crankshaft with oil pump gear assembly’ (1005015-81Д). This is the crankshaft itself, the core of the FAW Crankshaft And Flywheel Assembly. This forged, hardened steel component is the backbone of the engine, featuring precision-machined journals for the main bearings and connecting rod bearings. This specific part number indicates that the crankshaft comes as an assembly with the main oil pump drive gear already installed.

Adjacent to the oil pump gear is the ‘Crankshaft timing gear’ (1005037-81Д). This gear is the “master” gear for the entire engine. It is keyed or heat-pressed onto the crankshaft’s “snout.” Its teeth mesh with the idler gears that, по очереди, drive the camshaft(s) and the high-pressure fuel injection pump. The timing of this gear is absolutely critical for engine operation. A single tooth of misalignment in this part of the FAW Crankshaft And Flywheel Assembly will result in bent valves, damaged pistons, and catastrophic engine failure.

Also listed is the ‘Main drive gear and flywheel dowel pin’ (1005031-29Д). This small, hardened steel pin is pressed into the crankshaft flange. It ensures the flywheel can only be mounted in one specific orientation. This is critical for indexing the timing marks on the flywheel and for maintaining the precise rotational balance of the entire FAW Crankshaft And Flywheel Assembly.

Silicone Oil Damper Assembly (1005195-81Д)

At the very front of the FAW Crankshaft And Flywheel Assembly is the ‘Silicone oil damper assembly’ (1005195-81Д), also known as the harmonic damper or balancer. A diesel engine’s violent power strokes do not create a smooth spin; they cause the long crankshaft to twist and “кольцо” like a bell. This is called torsional vibration, and it can destroy an engine.

This damper is a heavy outer inertia ring that is bonded to a central hub via a thick layer of viscous silicone fluid. This assembly is “tuned” to the engine’s specific resonant frequency. As the crank twists, the outer ring “lags” behind due to inertia, and this shearing action through the silicone fluid creates friction, which converts the harmful vibration into simple heat. A high-quality damper is essential for the smooth operation of the FAW Crankshaft And Flywheel Assembly.

A failing damper (НАПРИМЕР., leaking silicone, or the outer ring slipping on the hub) is a critical failure. It will cause a severe, new engine vibration and will quickly destroy main bearings, snap accessory brackets, or even fatigue the crankshaft itself. The entire FAW Crankshaft And Flywheel Assembly relies on this part for a long service life.

Front-End Pulleys and Fasteners

The front-end of the FAW Crankshaft And Flywheel Assembly is a busy hub of components. The ‘Poly-V belt pulley’ (1005046A81D) is bolted to the front of the harmonic damper. This is the main pulley that drives the engine’s serpentine belt, powering accessories like the alternator, водяной насос, and A/C compressor.

A complex set of fasteners secures this entire front stack. The ‘Silicone oil damper assembly’ is secured to the crankshaft hub by eight ‘Damper bolts’ (1005048-53Д). The ‘Poly-V belt pulley’ is then secured to the damper using 12 ‘Hex flange bolts’ (Q1841020). And the entire hub assembly is often held onto the crankshaft snout by a single, massive central bolt, the ‘Hex flange bolt – enlarged series’ (Q1862040(полупансион)).

Each of these bolts is a high-tensile, critical fastener that must be torqued in the correct sequence to ensure the entire FAW Crankshaft And Flywheel Assembly spins true, without wobble. A loose or improperly torqued pulley can shear its bolts, leading to a total loss of engine accessories.

FAW Crankshaft And Flywheel Assembly Parts List

The following table provides the complete, detailed breakdown of all components identified in the ‘Crankshaft and Flywheel Assembly’ diagram for the FAW CA4251P66K24T1A3E5 tractor. Using genuine parts for your FAW Crankshaft And Flywheel Assembly is crucial for ensuring proper balance and reliability.

Technical Specifications and Assembly Context

The specifications for the FAW Crankshaft And Flywheel Assembly are centered on its critical role as the main rotating mass of the engine, designed for maximum durability and balance.