Connecting rod in a two stroke marine engine is used to connect the crankshaft and the piston (via crosshead and piston rod) for transmitting the piston force to the crankshaft.
In 2 Stroke engines, the con-rod is one of the most stressed part as it undergoes high compressive forces.
The 2 stroke con-rod is constructed in round section with flat palm at both ends to accommodate bearings.
Material
Connecting rod are forged from mild or medium steel (UTS- 500 MN/ sq.m), which is strong and light in weight, to keep the inertia forces low.
2 Stroke Marine Engine Connecting Rod arrangement with piston rod and Crankshaft
Reasons Behind Failure of Connecting Rod
As connecting rod is one of the most stessed components in the marine engine, the failure of connecting rod can be due to:
- Very high peak pressure inside the combustion chamber
- Water inside the cylinder while starting the engine
- Crankpin bearing seizure
- Piston or liner seizure due to lack of lubrication or cooling
- Wrong or loose assembly of connecting rod parts
Inspection of Con-Rod
When doing the inspection of connecting rod, check for the following:
- Cracks in the body of connecting rod
- Connecting rod bolts locking arrangement
- Fracture sign in the body
- Buckling of con-rod
