Why Vehicle Manufacturers Use Different Firing Orders: The Case of Chevrolet, Ford, and Dodge

Introduction

Vehicle manufacturers use different firing orders for their engines, and one common example is the small block Chevrolet, Ford, and Dodge V8 engines. These engines employ distinct firing sequences that contribute to engine performance and balance. In this article, we'll explore why these different firing orders exist and whether one is better than the other.

Air Compressor Example with a 302 Ford Small Block

Years ago, my uncle purchased an air compressor that utilized a 302 Ford Small Block engine. The engine was configured in a unique way, with half of the cylinders used for air compression and the other half for engine operation. This fascinating setup is a perfect illustration of how engines function in a similar manner to air pumps.

Firing Order Basics

A firing order is a sequence that ensures even distribution of power among the engine's cylinders. In a V-8 engine, for example, the firing sequence is typically 1-8-4-3-6-5-7-2. The sequence starts with the front-most cylinder on the right side, as seen from the front of the engine, and alternates in pattern across the banks of cylinders.

For modern inline engines, the firing order alternates front to back. On a Honda inline-four, for example, the sequence is 1-3-4-2, which can also be visualized as 3-4-2-1. Regardless of the specific order, the goal remains to maintain balance and reduce vibrations.

Engine Balance and Firing Sequences

The firing order is intricately linked to the design of the crankshaft. Most V8 engines are designed with a crossplane crankshaft that provides good secondary balance, but it requires heavy counterweights to smooth out the primary imbalance caused by pistons moving at different times in their strokes. In contrast, a flat plane V8 resembles two inline-four engines put together, offering good primary balance but with more pronounced secondary imbalance and greater vibration.

A crossplane V8 is smooth but requires more mass for stability, while a flat plane V8 is lighter and freer revolving but more "buzzy". These distinctions impact engine performance and balance, leading to varied firing sequences.

Conclusion

In summary, the choice of firing order in vehicle engines is driven by engineering considerations like balance and performance. Whether a vehicle's engine uses a crossplane or flat plane crankshaft, the firing sequence is designed to provide the best possible balance. While one firing order might not be inherently better than the other, they each offer distinct advantages in different applications.