Description
Product Overview
The plunger pair is the core precision component of the mechanical fuel injection pump that generates high-pressure fuel. The cam drives the plunger to reciprocate and slide, and the control holes open and close to complete the oil suction, pressure application, and oil return cycle, precisely controlling the fuel injection volume of a single cylinder. Under long-term mining and construction conditions where the engine is subjected to 24-hour high-temperature and heavy-load operations, with impure diesel containing impurities, the outer wall of the plunger is scratched and the sealing gap expands. The supply pressure continuously decreases, and the fuel injection volume of each cylinder becomes unbalanced, causing the engine's power to decline, black smoke to exceed standards, and idle operation to shake. This product features an integrated precision plunger that undergoes comprehensive testing for high-pressure sealing and uniform fuel supply at the factory. The dimensions are standardized, and disassembly and assembly do not require grinding for compatibility. It is suitable for maintenance of direct injection pumps for medium and heavy-duty trucks, agricultural machinery, and large construction machinery.
Unique core advantages of this product
Red cover with transparent independent sealing tube protection, providing comprehensive protection during storage and transportation.
Each plunger is individually encapsulated in a transparent hard plastic tube, paired with a red sealing thread cover, completely isolating dust, moisture, and impact damage to the precise sliding working surface of the plunger. Long-term storage is not prone to rust or contamination with impurities. The components inside the box are intact and undamaged, facilitating maintenance stores to categorize and stockpile.
Multi-stage stepped smooth plunger rod, stable coaxial reciprocating motion
The plunger rod adopts a multi-stage stepped integrated design, with smooth arc transitions between segments. It moves in the pump cylinder without skew or unilateral wear. The supply stroke remains constant during long-term bumpy operations, reducing the difference in fuel injection volume among cylinders, and making idle operation more stable.
Side-side precise oil return drainage holes, linear and smooth oil quantity adjustment
A standard-sized oil return drainage hole is set in the middle section of the plunger, precisely matching the oil quantity adjustment gear ring of the oil pump. Under high and low load conditions, the oil control and pressure relief response is smooth, eliminating acceleration jolts, large speed difference in power, and obvious color differences in exhaust.
Thickened rear end pressure-bearing limit base, resistant to impact and不易变形
The rear end is widened and thickened for pressure-bearing， which can withstand the high-frequency reciprocating impact force of the reset spring. The pressure-bearing area is sufficient， resisting the impact of high-pressure fuel and preventing bulging or deformation. It maintains a micrometer-level sealing gap between the plunger and the pump cylinder for a long time， eliminating internal oil pressure leakage and pressure loss.
Overall nitrided hardened alloy steel， wear-resistant and corrosion-resistant， with a long service life
The entire plunger is processed from high-hardness alloy steel， with surface nitriding hardening + mirror polishing treatment. The outer wall is smooth and wear-resistant， and diesel gums and hard impurities are not prone to scratching or damaging the plunger. It is suitable for harsh operating environments with high dust.
Micro-hole non-scratch oil passage technology，不易积碳卡滞
The inner wall of the oil return drainage holes is mirror polished without processing burrs， making it difficult for diesel impurities and gums to adhere and accumulate. This reduces plunger sticking， oil pump supply interruption faults， and the frequency of frequent disassembly and maintenance. Applicable scenarios
This product is suitable for medium and heavy-duty freight trucks, agricultural tractors, wheeled loaders, and high-power fixed diesel generators equipped with mechanical direct injection fuel supply systems. It is applicable to mining areas, construction sites, and 24-hour full-load, high-temperature, and high-pollution mechanical diesel engines with diesel engine fuel injection pumps. It is suitable for major repairs.
Product basic parameters
Product name: Fuel Injection Pump Piston Pair
Part number: 247726
Main material: Integral nitrided hardened alloy steel
Structural features: Multi-stage stepped piston rod, side-side guide oil return holes, thickened tail pressure-bearing limit base, red cover transparent independent protective tube
Application conditions: 24-hour continuous full-load, long-term high-temperature in engine compartment, outdoor high-pollution medium and heavy-duty mechanical diesel engine fuel injection pump
Product status: New precision piston pair, factory completed with full calibration and testing of clearance, high-pressure sealingity, and fuel supply stroke
Packaging: Each unit is separately packaged in a red cover transparent protective tube. The piston ends are internally equipped with plastic protective plugs to isolate the precise sliding working surfaces from transportation impacts and scratches, supporting single-piece, multi-box batch purchases, and compatible with cross-border small items / full container logistics.
