BMW typically numbers inline-engine cylinders from the front of the engine toward the rear, starting with cylinder 1 near the timing gear. In V engines, numbering starts with Bank 1 (the bank that contains cylinder 1) and proceeds along that bank, with Bank 2 containing the remaining cylinders (for a V8, 1–4 on Bank 1 and 5–8 on Bank 2; for a V12, 1–6 on Bank 1 and 7–12 on Bank 2).
Understanding this scheme helps with maintenance tasks such as spark plug replacement, fuel injector work, ignition coil placement, and interpreting service documentation. The specific position of cylinder 1 and the bank layout are defined by BMW's engine family and are documented in the workshop manuals for each model. In practice, you should verify using the engine's stamped numbers or service literature for your VIN and engine code.
Inline engines: single bank
Most modern BMW four- and six-cyl engines are inline (I4, I6). In these configurations there is a single cylinder row; numbering runs from the front, where cylinder 1 sits near the timing gear, toward the rear. This simple progression keeps maintenance straightforward.
- Inline-4: cylinders are numbered 1 through 4 from the timing-gear end toward the back of the engine.
- Inline-6: cylinders are numbered 1 through 6 from front to back.
These examples reflect BMW's common practice for inline configurations, but consult the specific engine code for precise layout, as there can be variations across generations or special editions.
V engines: two banks
BMW's V-series engines organize cylinders into two banks. Bank 1 is defined as the bank containing cylinder 1; Bank 2 contains the remaining cylinders. Within each bank, cylinders are numbered sequentially from front to rear along that bank. For a V8, Bank 1 carries cylinders 1–4 and Bank 2 carries 5–8; for a V12, Bank 1 carries 1–6 and Bank 2 carries 7–12.
- V8: Bank 1 cylinders 1–4; Bank 2 cylinders 5–8.
- V12: Bank 1 cylinders 1–6; Bank 2 cylinders 7–12.
Again, the exact front-to-back orientation of Bank 1 versus Bank 2 can vary with model and era, so always confirm with the vehicle’s service manuals or the engine stamping on the valve covers for your specific car.
How to verify cylinder numbering on your BMW
To confirm the numbering for a given model, use one of these methods: consult the factory service information for your engine code, check the label on the engine cover or near the intake manifold, compare spark plug or coil pack positions with the bank numbers, or reference the workshop manual for the exact cylinder map. If in doubt, contact a BMW technician or use a reputable repair database.
Summary
BMW uses a consistent rule: inline engines count cylinders from the front (cylinder 1 at the timing-gear end) toward the rear; V engines designate Bank 1 as the bank containing cylinder 1 and number that bank 1 from 1 upward, with Bank 2 carrying the remaining cylinders (e.g., 5–8 for a V8, 7–12 for a V12). Always verify with the engine code and official documentation for your specific model, as there can be exceptions across generations and special editions.