About the 4G93 Engine
The 4G93 engine is a four-cylinder, 1.8-liter gasoline engine produced by Mitsubishi Motors. It belongs to the Mitsubishi 4G9 engine family, which has been in production since the late 1980s. The 4G93 engine is known for its reliability, performance, and fuel efficiency. It has been used in various Mitsubishi models, including the Lancer, Mirage, and Galant, as well as in some Proton and Hyundai vehicles. One important aspect of maintaining this engine is ensuring proper torque specifications for the head bolts, which play a crucial role in the engine’s overall performance and longevity.
Head Bolt Torque Specifications for the 4G93 Engine
To ensure the proper sealing and integrity of the engine’s cylinder head, it is essential to tighten the head bolts to the correct torque specifications. The following table provides the recommended torque values for the head bolts of the 4G93 engine:
| Head Bolt | Torque Specification (ft. lbs.) | Torque Specification (Nm) |
|---|---|---|
| 1 | 22-25 | 30-34 |
| 2 | 22-25 | 30-34 |
| 3 | 22-25 | 30-34 |
| 4 | 22-25 | 30-34 |
| 5 | 22-25 | 30-34 |
| 6 | 22-25 | 30-34 |
| 7 | 22-25 | 30-34 |
| 8 | 22-25 | 30-34 |
Procedure for Torquing the Head Bolts
To properly torque the head bolts of the 4G93 engine, follow these steps:
1. Start by cleaning the threads of the head bolts and the bolt holes in the engine block using a suitable cleaning agent and a brush.
2. Apply a small amount of engine oil to the threads of each head bolt.
3. Begin tightening the head bolts in a specific sequence. It is crucial to follow the correct tightening sequence to ensure even distribution of the clamping force. The recommended sequence is usually provided in the vehicle’s service manual.
4. Use a torque wrench to tighten each head bolt to the specified torque value in a clockwise direction. Gradually increase the torque in multiple steps, following the recommended torque sequence.
5. After reaching the final torque value, allow the engine to sit for a few minutes to allow for any relaxation of the bolts.
6. Repeat the torque sequence and tighten each head bolt to the specified torque value once again.
7. Double-check that all head bolts are tightened to the correct torque specification.
8. Finally, recheck the torque of each head bolt after the engine has gone through a heat cycle, typically after a few hundred miles of driving.
Following the proper torque specifications and tightening procedure for the head bolts of the 4G93 engine is crucial to ensure a secure and leak-free seal between the cylinder head and the engine block. This helps maintain the engine’s performance, reliability, and longevity.