6CT Diesel Engine Spare Parts Engine Piston 3929161 3802657

Desc.

Piston

Part No/TC type

3929161 3802657

Brand Name

Man, ABB, PBS, KBB, Napier MET, Weicai, JTH

Other parts

pls contact freely
if you need other P/N

Engine Type

Diesel engine,Gas engine,
Diesel Generators etc.

Spare Type

Cartridge, Nozzle ring , shaft, rotor complete, compressor wheel, diffuser, turbine casing , compressor casing , bearing casing, turbine blades, bearing

Condition:

Original , brand new, OEM, replacement, refurbished

Applicable industry

Marine engines,
Construction works ,oil platform
Energy & Mining etc

Key Word:

Original spare parts
and engine repair tool kits

Trade terms

FOB EXW CIF DDU DDP,

Door to door is available in some countries.

Delivery time:

Most parts are in stock, bulk order based on qty

Payment

T/T, L/C,D/A, Alipay, Western Union, Paypal etc.

Place of origin

China/Germany/South Korea USA/Japan/Sweden /UK/Singapore/Taiwan

Package

Neutral or original packaging

About the product

The piston is a critical component within the cylinder block of an automobile engine that undergoes reciprocating motion. Its fundamental structure can be divided into three primary sections: the top, the head, and the skirt. The piston's top forms a significant portion of the combustion chamber, with its shape determined by the selected combustion chamber design. Most gasoline engines employ flat-top pistons due to their advantage of having a reduced heat absorption area. In contrast, diesel engine pistons often feature various types of depressions, with their specific shapes, positions, and dimensions tailored to meet the requirements for mixture formation and combustion in diesel engines.

### Operating Conditions
The piston operates under extreme conditions characterized by high temperatures, high pressures, high speeds, and inadequate lubrication. Direct contact with high-temperature gases exposes the piston to instantaneous temperatures exceeding 2500K, leading to significant thermal loading while presenting poor heat dissipation conditions. Consequently, the piston operates at elevated temperatures, with the top reaching 600–700K, and the temperature distribution being highly non-uniform. Additionally, the piston's top experiences substantial gas pressure, particularly during the power stroke, where pressures can reach up to 3–5MPa in gasoline engines and 6–9MPa in diesel engines. This results in impact forces and lateral pressure acting on the piston. Furthermore, the piston moves back and forth within the cylinder at high speeds (8–12m/s), with continuously varying velocity, generating considerable inertial forces and imposing significant additional loads on the piston. Under these harsh operating conditions, the piston is prone to deformation and accelerated wear, as well as experiencing additional loads, thermal stress, and chemical corrosion from combustion gases.

### Piston Inspection
Piston inspection primarily involves measurements of the skirt diameter, the height of the piston ring groove, and the size of the piston pin seat hole:
① The selection and matching of pistons should be based on the repair size of the cylinder. Typically, the increased size value is indicated on the top of the piston.
② Within the same series of engines, the structural design of pistons may vary. Therefore, when purchasing pistons, it is essential to select the appropriate type corresponding to the engine model. On the same engine, pistons from the same manufacturer, group, or product code should be used. For the same engine model, pistons with the same product code must be employed to ensure that the differences in piston diameter and mass remain within the range specified by the original equipment manufacturer (OEM). Failure to adhere to these guidelines may result in poor combustion, rough operation, and diminished economic and power performance of the engine. Thus, when selecting and matching pistons, the appropriate type must be chosen according to the engine model.