Cylinder Head Repair Specification Example for Assembly Programmes: High Performance
Cylinder Head Repair Specification Example for Assembly Programmes: High Performance
This is a worked specification for cylinder head repair 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 assembly programmes is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually lead time that slipped twice before bulk started.

Example specification
| Item | Cylinder Head Repair |
|---|---|
| Application | Assembly Programmes |
| Version | High Performance |
| Base material | ABS Plastic |
| Controlled dimensions | 5 key dimensions, recorded per lot |
| Tolerance band | ±0.5 mm |
| Finish | zinc plated |
| MOQ | 3,000 pieces per specification |
| Sampling | 7 working days, 5 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 — ABS Plastic, 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
- injection moulding
- heat treatment
- precision stamping
- sintering
- anodising
- laser cutting
Where this example applies
Programmes that run high performance most often specify this build for assembly programmes. Related applications include long-haul trucks, rental motorcycles, scooter fleets, racing teams, agricultural trailers.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 2.5 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 SAE J431-compliant build instead of a fresh interpretation.
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.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 3000 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.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



