Aluminum Cylinder Head Specification Example for Three-Wheelers: Sealed Unit
Aluminum Cylinder Head Specification Example for Three-Wheelers: Sealed Unit
This is a worked specification for aluminum cylinder head in a sealed unit 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 sealed unit version exists because the duty cycle on three-wheelers 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 | Aluminum Cylinder Head |
|---|---|
| Application | Three-Wheelers |
| Version | Sealed Unit |
| Base material | Kevlar Composite |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | powder coated |
| MOQ | 1,000 pieces per specification |
| Sampling | 7 working days, 5 days per revision |
| Compliance | SGS |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Kevlar Composite, 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
- die casting
- sintering
- assembly line testing
- precision stamping
- gravity casting
- rubber vulcanisation
Where this example applies
Programmes that run sealed unit most often specify this build for three-wheelers. Related applications include off-road bikes, construction equipment, long-haul trucks, export programmes, boat 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 SGS-compliant build instead of a fresh interpretation.
What is the minimum order quantity?
The standard MOQ is 1000 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
How long does sampling take?
Samples leave the factory in 7 working days, and each revision round adds about 5 days once you have seen the first piece.
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.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



