Four-Stroke Engine Specification Example for City Buses: High Performance
Four-Stroke Engine Specification Example for City Buses: High Performance
This is a worked specification for four-stroke engine in a high performance programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The high performance version exists because the duty cycle on city buses is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually packing that arrived crushed at the port.
Example specification
| Item | Four-Stroke Engine |
|---|---|
| Application | City Buses |
| Version | High Performance |
| Base material | Nylon 66 |
| Controlled dimensions | 5 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | anodised |
| MOQ | 1,000 pieces per specification |
| Sampling | 7 working days, 5 days per revision |
| Compliance | DOT |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Nylon 66, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.
Processes involved
- surface grinding
- precision stamping
- cold forging
- robot welding
- electroplating
- shot blasting
Where this example applies
Programmes that run high performance most often specify this build for city buses. Related applications include passenger cars, utility trailers, scooter fleets, trailer axles, agricultural trailers.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the DOT-compliant build instead of a fresh interpretation.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 1000 pieces per line.
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
What testing is included?
Standard lots ship with dimensional and hardness reports. DOT documentation is issued with the shipment when your market requires it.
Ask for the current catalogue and the specification sheet for this line.
