Techniques for Replacing Bearings on a Single-Cylinder Diesel Engine

When a single-cylinder diesel engine experiences bearing failure and seizure, the bearings can be replaced using the following method, with shaft resurfacing if necessary. This method is simple and easy to perform, requiring no disassembly of the cylinder head and piston-connecting rod assembly, nor adjustment of valve clearance, saving both time and effort.

1. If the crankshaft cannot turn, first remove the drive belt from the flywheel, pry flat the flywheel nut locking plate, then place a special flywheel removal wrench on the flywheel nut and tap the wrench handle clockwise with a hammer. Generally, the flywheel will then turn.

2. Remove the gear chamber cover, gears, and rear cover, unscrew the flywheel nut, and pull out the flywheel.

3. Use a suitable bent-end socket wrench to loosen the connecting rod bolts. After decompression, rotate the crankshaft until the piston is at top dead center. Then remove the main bearing cap bolts, push out the main bearing cap, reach under the rear cover and unscrew the connecting rod bolts, remove the connecting rod cap, pull the crankshaft out from the engine side, and secure it with a wire threaded through the bolt hole on the connecting rod big end. 4. Determine the repair method based on the corrosion condition of the crankshaft journal and replace the bearings accordingly.

5. After installing the main bearings as usual, install the crankshaft. Rotate the crankshaft to make the crankshaft crank backward, then pull the wire tied to the connecting rod big end to move the piston-connecting rod assembly to its lower dead center until the connecting rod big end and connecting rod journal are in contact. Then, insert the upper bearing plate from the rear between the connecting rod big end and journal, while the lower bearing plate is pressed into the connecting rod cap. Then, tighten the connecting rod bolts by hand and install the main bearing caps.

6. After tightening the connecting rod bolts to the specified torque, reassemble all the disassembled parts.