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[Datsun 1200 encyclopedia]

Valve springs

From Datsun 1200 Club

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Category: Valvetrain

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



Datsun dual springs are installed a special direction. The close-coil end goes next to the cylinder head
132d.jpg 27459.jpgAlbum 27459

GX springs use the standard valve retainer with a special stepped seat
504.jpgAlbum 504 27458.jpgAlbum 27458

Specs and Testing

15332.jpgAlbum 15332

* 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 excess deflection must be replaced.
* Squareness deformation limit: 1.6 mm (1.3 for dual springs)

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 [all after 1973]
* 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
* 13203-H2300 SPRING-valve, outer GX
* 13203-H2301 SPRING-valve, inner GX
* 13205-H2300 SEAT-valve spring GX
  174_5666a42e95c11.jpgPost 474291

collets (half-circles) lock the valve assembly to the valve stem
2602_60415dcc23848.jpgPost 496255 2602_60415dd51dcd8.jpgPost 496255

Valves & Seals

Main: Valves

1501.jpg 23353.jpg

Racing Valve Springs

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

 V I D E O  resorte de valvulas filmado a 9200 rpm valve spring (click to view)
  • Stock springs are redlined at 6400 rpm, and will often go to 6800 RPM
  • Factory GX springs are good to about 7500 rpm (higher than the points distributor will rev)
  • Tomei

Dual Valve Springs

Large valves work best at high RPM. When revving over 6000 RPM, dual valve springs are called for. The stock A12GX springs are good for 6600 RPM (and some report higher RPMs).

Racing/aftermarket dual springs are usually good for 9000 RPM and shouldn't be used in a street engine as they cause accelerated wear on the valve guides.

19821.jpgAlbum 19821 21686.jpgAlbum 21686 21687.jpgAlbum 21687 23378.jpgAlbum 23378 23647.jpgAlbum 23647 23648.jpgAlbum 23648 23649.jpgAlbum 23649 23734.jpgAlbum 23734

Triple Valve Springs

18703.jpgAlbum 18703

  • Iskenderian 455-JA-006 needs dual spring retainers, MAX RPM 10,000


Toyota Dyna inner valve springs
L14 dual valve springs
L-series is slightly taller, 
and compresses slightly more
* L-series 1.98" free length, 1.524" at 52.7 lb
* A-series 1.83" free length, 1.575" at 46.9 lb
Holden Six dual valve springs
ISKY 455-D/JA-006
MAX RPM 10,000
Outer     455-D
  O.D.   1.210"
  I.D.    .925"
Inner    JA-006
  I.D.    .635"
Spring rate 225
Coil bind .850"
installed height   1.500"
Max net valve lift  .450"
1.500"  79 lbs
1.200" 145 lbs

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