Une vue éclatée des pièces détaillées: Bloc-cylindres FAW pour tracteur CA4251P66K24T1A3E5

This essential technical guide provides a detailed analysis of the Bloc-cylindres FAW assemblée, a core component of the power system for the formidable FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This document serves as a definitive resource for identifying every part within this critical assembly.

We offer a comprehensive exploded view that deconstructs the major structural components and associated procurement items of the Bloc-cylindres FAW. This analysis breaks the unit down to its smallest serviceable part, from the main cast body and bearing caps to individual dowel pins, lifting bolts, and sealing plugs.

This guide is an indispensable resource for service technicians, parts managers, and fleet owners who require absolute precision for maintenance, repairs, or complete engine overhauls. Understanding the specific assembly and component part numbers of the Bloc-cylindres FAW is fundamental to ensuring the engine’s long-term performance, fiabilité, and structural integrity.

An In-Depth Look at the Cylinder Block Assembly

Le Bloc-cylindres FAW (Partie no. 1002014-99R.) is the foundational chassis of the engine. It is not merely a single piece but a complex assembly of precisely engineered components. This structure houses the cylinders, pistons, and crankshaft, and provides the rigid framework necessary to contain the immense forces of combustion and support all auxiliary components.

This specific block is designed for the high-torque, heavy-duty applications of the CA4251P66K24T1A3E5 tractor. Its design incorporates intricate passages for coolant and lubricating oil, which are essential for thermal management and friction reduction. The ‘Valve Head-Cylinder Body’ (Partie no. 1002023-81D) indicates a sophisticated, multi-part construction, likely optimizing airflow, valvetrain integration, or component access.

Maintenance personnel will note the various plugs listed, such as the ‘Cup Plugs’ (Q72232(HB), CQ72240, CQ72224) and ‘Inner Hex Tapered Screw Plugs’ (Q61902, Q61906). These are critical for sealing the coolant and oil galleries created during the manufacturing (casting) process. Knowing their precise locations and part numbers is vital for preventing catastrophic leaks during a rebuild or major service.

The inclusion of ‘Lifting Bolts’ (1002021-53D) further emphasizes the service-oriented design of the Bloc-cylindres FAW. These designated attachment points are engineered to allow technicians to safely and securely hoist the entire block assembly, which weighs a significant amount, using appropriate shop equipment. This is essential for any major overhaul or replacement, safeguarding both the component and the technician.

Cylinder Block Casting and Core Structure

The architecture of the Bloc-cylindres FAW is a testament to modern foundry and machining processes. Forged from a high-strength, premium-grade cast iron or specialized alloy, the block is designed to offer maximum rigidity while managing weight. This rigidity is paramount; it prevents warping and misalignment of moving parts, such as the crankshaft and pistons, under the extreme temperatures and pressures of a modern diesel engine. The main body (1002014-99R.) serves as the structural backbone, integrating the cylinder bores, the upper crankcase, and all the mounting points for external engine accessories like the alternator, entrée, and manifolds.

The ‘Valve Head-Cylinder Body’ (1002023-81D) is another significant structural component listed. This part, identified as a single unit, likely forms the upper section of the block or a specific, complex housing integrated directly into the main casting. Its function could be related to housing parts of the valvetrain (like lifters or camshafts, in an non-overhead-cam design) or managing the flow of air and exhaust. Its integration directly into the block assembly highlights a robust design philosophy focused on durability and reducing the number of potential gasket failure points.

Analysis of Sealing Components and Serviceable Units

A modern engine block is a complex network of drilled passages for fluids. The ‘Cup Plugs’ and ‘Screw Plugs’ in the Bloc-cylindres FAW parts list are the critical components that seal these passages. During the manufacturing process, sand-casting cores are held in place, and long drill bits create the necessary pathways for oil and coolant to circulate throughout the engine. These processes inevitably leave holes in the casting that must be permanently and reliably sealed.

The parts list shows multiple types and quantities: ‘Cup Plugs’ (Q72232(HB), CQ72240, CQ72224) are typically thin, dome-shaped metal discs that are pressed into a precisely-machined hole. They flatten slightly upon installation to create a tight, friction-based seal. These are often used to seal the ends of coolant passages and the holes left from the casting sand cores. They are sometimes referred to as “freeze plugs.”

Conversely, the ‘Inner Hex Tapered Screw Plugs’ (Q61902, Q61906) are threaded plugs. As their name suggests, they have a tapered thread and an internal hexagonal drive (for an Allen key). This tapered design ensures a tight, metal-to-metal seal as they are tightened into a corresponding threaded hole. These are almost always used to seal the high-pressure oil galleries, which supply lubrication to the crankshaft, arbre à cames, and other vital components.

For a technician, all these plugs are critical serviceable units. During any major engine overhaul, especially one that involves ‘hot tank’ cleaning or crack-testing the block, all of these plugs must be removed to ensure the block is thoroughly cleaned inside and out. Replacing them with new, genuine parts upon reassembly is not optional—it is mandatory. Re-using old, stressed plugs is a common cause of post-rebuild fluid leaks. Having the exact part numbers (like CQ72240, of which there are 11) is essential for ordering the correct service kit for the Bloc-cylindres FAW.

Crankshaft Support: Main Bearings and Caps

A critical aspect of this architecture, and one central to engine longevity, is the main bearing assembly. The crankshaft, which converts the pistons’ linear force into rotational power, is secured to the underside of the block by a series of ‘Main Bearing Caps’ (1002011-81D) and a specific ‘Rear Main Bearing Cap’ (1002012-81D). This parts list identifies six standard caps and one rear cap, typical for an in-line six-cylinder engine. These caps are precision-machined in tandem with the block itself, creating a perfect circle (the bearing bore) for the bearing shells. They are not interchangeable and must be reinstalled in their original positions and orientation.

Precision Fasteners and Alignment

These caps are held in place by 14 ‘Main Bearing Bolts’ (1002013AS3D-S). These are not ordinary bolts; they are high-tensile, critical-fastener components, often of a torque-to-yield (TTY) conception. This means they are designed to be stretched to a specific point upon installation to provide a precise clamping force. Following the factory torque specifications and tightening sequence for these bolts is absolutely essential for a successful engine build. Failure to do so can lead to bearing failure and catastrophic damage to the Bloc-cylindres FAW and crankshaft.

Precision alignment is a non-negotiable requirement in engine building. To achieve this, le Bloc-cylindres FAW assembly relies on multiple ‘Dowel Pins’. We see ‘Dowel Pins’ of various sizes (Q5211020, Q5211232, Q5210814) listed in the parts diagram. These small, seemingly simple components play a crucial role. They precisely locate the main bearing caps, the valve head-cylinder body, the cylinder head (not pictured), and the transmission bell housing *before* the bolts are tightened. This ensures perfect alignment of oil galleries, coolant passages, and the cylinder bores relative to the crankshaft, preventing component stress and potential failures.

FAW Cylinder Block Assembly Parts List

The following table provides a detailed breakdown of the components associated with the Bloc-cylindres FAW assemblée, as specified for the FAW CA4251P66K24T1A3E5 tractor. Using genuine FAW parts with the correct part numbers is essential for ensuring proper fit, function, and reliability during service or repair.

Key Technical Specifications & Contexte

While the Bloc-cylindres FAW is the foundation, its specifications are defined by its role within the complete engine. The parameters below relate to the block and the typical engine it supports, providing essential context for its structural, thermal, and mechanical duties.