Engine Piston Ring Set Specification Example for City Buses: Two-Piece Construction
Engine Piston Ring Set Specification Example for City Buses: Two-Piece Construction
This is a worked specification for engine piston ring set in a two-piece construction 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 two-piece construction 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 inconsistent hardness between lots.
Example specification
| Item | Engine Piston Ring Set |
|---|---|
| Application | City Buses |
| Version | Two-Piece Construction |
| Base material | Semi-Metallic Compound |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.1 mm |
| Finish | painted |
| MOQ | 500 pieces per specification |
| Sampling | 10 working days, 3 days per revision |
| Compliance | TUV |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Semi-Metallic Compound, 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
- powder coating
- precision stamping
- CNC machining
- sintering
- cold forging
- laser cutting
Where this example applies
Programmes that run two-piece construction most often specify this build for city buses. Related applications include construction equipment, city buses, fleet maintenance, workshop replacements, courier fleets.
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
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 3 days once you have seen the first piece.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the TUV-compliant build instead of a fresh interpretation.
What is the minimum order quantity?
The standard MOQ is 500 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
Ask for the current catalogue and the specification sheet for this line.
