The 4.6L Cadillac Northstar engine, a 90-degree V8, utilizes a specific firing order optimized for smoothness and balance:
Firing Order: 1-2-7-3-4-5-6-8
Cylinder Bank Identification:
- Left Bank (Driver Side USA): Cylinders 1, 3, 5, 7
- Right Bank (Passenger Side USA): Cylinders 2, 4, 6, 8
Sequence Breakdown:
- Ignition starts at Cylinder 1 (Left Front).
- Next spark occurs at Cylinder 2 (Right Front).
- The sequence then fires Cylinder 7 (Left Rear).
- Followed by Cylinder 3 (Left Center-Front).
- Then Cylinder 4 (Right Center-Front).
- Then Cylinder 5 (Left Center-Rear).
- Then Cylinder 6 (Right Center-Rear).
- Finally, Cylinder 8 (Right Rear) fires.
Why this Order?
This sequence (1-2-7-3-4-5-6-8) minimizes vibration and ensures optimal crankshaft rotation balance for a 90-degree V8 engine. It spaces ignition events evenly across both cylinder banks and alternates firing between banks where possible. The crankshaft design, with specific journal angles, physically dictates this firing sequence.
Key Feature: The Northstar engine complements its firing order with sophisticated counter-rotating balance shafts to achieve exceptional smoothness.