Valve springs

Revision as of 02:55, 21 November 2015; view current revision
<-Older revision | Newer revision->

The A12 engine in the Datsun 1200 uses traditional coil springs for each valve. The A12GX Engine uses dual springs on each valve.

Specs and Testing

* Free Length: 46.5 mm (1.831 in)
* Valve Closed: 38.7 mm at 23.9 kg (1.524 in at 52.7 lb)
* Valve Open: 30.2 mm at 58.5 kg (1.19 in at 129 lb)

1. Measure the free length and the tension of each spring. If the measured value exceeds the specified limit, replace the spring.
2. Check each spring for deformation with a square. Any springs with a deflection of 1.6 mm (0.0630 in) or more must be replaced.

Part Numbers

Nissan Part Numbers
* 13203-H1000 SPRING-valve, outer ALL except GX
* 13205-18000 SEAT-valve spring ALL except GX
* 13209-H2301 RETAINER-valve spring ALL
* 13210-73400 COLLET-valve
* 13210-H1000 COLLET-valve (from 72-2)
* 13210-U0100 COLLET-valve (from 71-10)
** All three collet PNs interchange
* 13219-H1000 SHROUD-valve, inner ALL except GX

GX-specific
* 13203-H2300 SPRING-valve, outer GX
* 13203-H2301 SPRING-valve, inner GX
* 13205-H2300 SEAT-valve spring GX

Valves & Seals

See main article: Valves

Racing Valve Springs

For RPMs in excess of stock (higher than 6400 RPM) use racing valve springs

* Stock springs are good to 6000 rpm
* Factory GX springs are good to 6400 rpm
* Tomei
* Iskenderian 455-JA-006 needs dual spring retainers, MAX RPM 10,000

Photo Index