Engine Piston Ring Set Specification Example for City Buses: Drilled and Slotted
Engine Piston Ring Set Specification Example for City Buses: Drilled and Slotted
This is a worked specification for engine piston ring set in a drilled and slotted 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 drilled and slotted 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 warranty claims traced back to a single lot.
Example specification
| Item | Engine Piston Ring Set |
|---|---|
| Application | City Buses |
| Version | Drilled and Slotted |
| Base material | EPDM Rubber |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.1 mm |
| Finish | as machined |
| MOQ | 3,000 pieces per specification |
| Sampling | 14 working days, 3 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — EPDM Rubber, 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
- anodising
- die casting
- injection moulding
- CNC machining
- precision stamping
- ultrasonic cleaning
Where this example applies
Programmes that run drilled and slotted most often specify this build for city buses. Related applications include city buses, construction equipment, passenger cars, long-haul trucks, off-road bikes.
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 you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
What testing is included?
Standard lots ship with dimensional and hardness reports. SAE J431 documentation is issued with the shipment when your market requires it.
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 is the minimum order quantity?
The standard MOQ is 3000 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.
