About the 4M40 Engine
The 4M40 engine is a diesel engine commonly used in Mitsubishi vehicles. It is a four-cylinder, turbocharged engine known for its durability and reliability. The 4M40 engine has been used in various Mitsubishi models, including the Pajero, Delica, and Canter. This engine is known for its excellent torque output and fuel efficiency, making it a popular choice for both commercial and recreational vehicles.
Head Bolt Torque Specifications
To ensure proper installation and sealing of the cylinder head, it is crucial to torque the head bolts to the manufacturer’s specifications. The head bolt torque for the 4M40 engine is as follows:
| Head Bolt | Torque (ft. lbs.) | Torque (Nm) |
|---|---|---|
| Bolt 1 | 22-25 | 30-34 |
| Bolt 2 | 51-54 | 69-74 |
| Bolt 3 | 51-54 | 69-74 |
| Bolt 4 | 22-25 | 30-34 |
| Bolt 5 | 22-25 | 30-34 |
Procedure for Torquing Head Bolts
To properly torque the head bolts on a 4M40 engine, follow these steps:
1. Start by cleaning the threads of the head bolts and the bolt holes in the engine block. Remove any dirt, oil, or debris that may affect the torque readings.
2. Apply a small amount of engine oil to the threads of each head bolt. This will help ensure proper lubrication during the torquing process.
3. Begin by torquing all the head bolts to 22-25 ft. lbs. (30-34 Nm) in a crisscross pattern. This initial torque will help evenly distribute the load on the cylinder head.
4. Next, torque bolts 2 and 3 to 51-54 ft. lbs. (69-74 Nm) in the same crisscross pattern. These bolts typically require a higher torque due to their location and the forces they experience.
5. Finally, torque bolts 1, 4, and 5 to 22-25 ft. lbs. (30-34 Nm) in the crisscross pattern. This will complete the torquing process and ensure the cylinder head is properly secured.
6. After torquing all the head bolts, it is recommended to perform a final pass at the specified torque values to ensure they are properly tightened.
Importance of Proper Head Bolt Torque
Properly torquing the head bolts is crucial for the integrity of the engine’s cylinder head. Insufficient torque can lead to head gasket failure, coolant leaks, and loss of compression. On the other hand, over-tightening the head bolts can cause damage to the cylinder head or even result in bolt failure.
By following the manufacturer’s specified torque values and the correct torquing sequence, you can ensure a secure and leak-free seal between the cylinder head and engine block. This will help maintain the engine’s performance and reliability over time.
In conclusion, the 4M40 engine is a reliable and efficient diesel engine commonly used in Mitsubishi vehicles. When it comes to torquing the head bolts, following the manufacturer’s specifications is essential to ensure a proper seal and prevent any potential issues. By carefully torquing the head bolts in the correct sequence, you can maintain the integrity of the engine and enjoy its performance for years to come.