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[Datsun 1200 encyclopedia]

Crankshaft Pulley

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Category: Engine Mechanical

Datsun 1200 Crankshaft Pulleys came in single-belt and double-belt type of the V-belt type. There was also a triple-belt type for other A-series engines.




Datsun A-series crank pulleys are just pulleys. They are not a Harmonic Balancer — the A-series engine is so well balanced it doesn't need one. The pulleys may or may not have balancing holes drilled on the back side or on the front side. These are to ensure the pulley is also balanced (the pulley is zero-balanced). NOTE that A-series engine are internally balanced, so all flywheels and crank pulleys interchange.

#Single Belt early: triangular holes. Late: round holes
20598.jpg 20602.jpgAlbum 20602

#Double-belt: Four kinds of front pulley: small, medium, large adjacent and & large skip



  Outside Diameter
Stock A-series:        139 mm (5.4 inch)
Nismo Option 1:        101 mm (4.0 inch)
Nismo Option 2:         75 mm (3.0 inch)
B122 aircon pulley 129 mm, 22 mm groove pitch 12303-G1615

Single-groove pulleys

1200 early pulley (1966-1972) has a single timing mark. Identified by the triangular holes.

1200 late pulley (1972-up) has multiple timing marks. Identified by the round holes.

All A-series
#Single-groove pulleys PULLEY-CRANKSHAFT
12303-18002 1966-1972 [Has multiple timing marks for early cover]
12303-H1001 -8109 [Has single timing mark for later Timing Cover]
12303-H1002 8110-8910 > 12303-H1001
12303-H8501 8910-
12303-H8500 B310.A14.S,K -7909
12303-H8501 B310.A14.S,K 7910-8010


Type 180 Single Belt triangular holes- Pre-1972 (multiple timing marks) 650g
20598.jpgAlbum 20598 17768_5365a14a253b6.jpgUpload click to view


Type H10 Single Belt round holes - Post-1972 (single timing mark) 740g

* From 1972.02

15885.jpgAlbum 15885 20602.jpgAlbum 20602 20601.jpgAlbum 20601 8262.jpgAlbum 8262


Type H85 used by Sunny Truck A12. Looks similar to #H10 but with a slightly larger hub/smaller triangular holes

120mm 600g

28573.jpgAlbum 28573 28572.jpgAlbum 28572

28577.jpgAlbum 28577 28576.jpgAlbum 28576

Twin-groove pulleys

dual-pulley/twin-groove/double sheave/W-pulley (for aircon use)
174_656fb5271eb3d.jpgPost 498094 9764_4fbb295d6b146.jpgUpload click to view

Type G16 129/129 mm with large center
Type H50
Type H72
Type H8900
Type H8905

Wプーリー W pulley

#Twin-belt pulleys (for factory cooler)
12303-M0110 7804-7907
12303-G1615 7908-
12303-H8900 B310 -8002
12303-H8905 B310 8003-, all A15
12303-H8905 C22 -0988
12303-G2511 C22 0988- <> 12303-G2512

Small W Pulley

Small center with puller holes
Large/small sheaves
28578.jpgAlbum 28578 20596.jpgAlbum 20596 20080.jpgAlbum 20080 28571.jpgAlbum 28571

The rear sheave is the basic 129/130mm size and the front one is the smallest.

Very similar looking to the 'large' W pulley, but has puller threads in the face of the pulley.

Small type has threads tapped into the face for a puller tool. This is the only size that has these extra holes.

Medium W Pulley

8-hole center (the only double-sheave that has perforations in the hub)

Diameter: 129mm
174_656ff3d564a8e.jpgPost 498095 174_656ff5350819a.jpgPost 498095 174_656ff543bd5f2.jpgPost 498095 174_656ff5ac6c19c.jpgPost 498095 174_656ff5d768ba6.jpgPost 498095 174_656ff5e6e4adc.jpgPost 498095 174_656ff5f6e85d5.jpgPost 498095

Pulley has the usual single timing mark to match the 1972-up Timing Cover
174_656ff3b044d4f.jpgPost 498095

Large W Pulley

Large/medium sheaves
25112.jpgAlbum 25112 28568.jpgAlbum 28568

The rear sheave is the basic 129/130mm size and the front one smaller (but larger than the other types)

Very similar looking to the 'small' W pulley, but has no puller threads in the face of the pulley like the small type

174_6570d204ce60f.jpgPost 498096 174_6570d25cb7862.jpgPost 498096

X-large W Pulley

G16 129mm - Sunny Truck from 7908
Large center
Large/large sheaves
174_656fb65abcab6.jpgPost 498094 174_656fb65abcab6.jpgPost 498094 20597.jpgAlbum 20597 28570.jpgAlbum 28570

Triple-groove pulleys

May or may not have indentations drilled on the back side. These are to ensure the pulley is balanced.

Sheave diameters
130, 134, 138 mm

Triple-Belt C22 with power steering
20595.jpgAlbum 20595 28569.jpgAlbum 28569

#Triple-belt pulleys
12303-M7061 N10.A14.POWER-STEERING
12303-G5110 C22 A/C + Power Steering

Part Numbers

Buy at Bprojects


B110 - 34.5mm OD, 0.64 in (16.2mm) ID, 8mm thick
* 12303-18002 PULLEY-CRANKSHAFT -0272 
  A10 & early A12 engines (multiple timing marks) 
* 12303-H1001 PULLEY-CRANKSHAFT 0272- B110 $37.66 
  (single timing mark)
B210 - all with single timing mark
* 12303-H1001 PULLEY-CRANKSHAFT 0272- B210 with A13 
* 12303-H5010 PULLEY-crankshaft (for cooler) B210 A12, A14 except USA (dual groove)
* 12303-H7201 PULLEY-CRANKSHAFT USA B210 with A14 (dual-groove) 
* 12303-H1001 same as B110
* 12303-H1002
* 12303-H8500 single pulley
* 12303-H8501
* 12303-H8900 dual pulley
* 12303-H8905 dual pulley

Pulley Bolt

12308-H1000 WASHER-PULLEY BOLT 1 A12 - $1.29 
12309-78200 BOLT-CRANK PULLEY 1 A12 - $5.73 
* M16 x 1.50 (fine) pitch 
* 15mm diameter 
* 27mm long 
* The head is 27mm hex and about 15 mm thick. 
* Torque: 15-16 kg/m (108-116 ft. lb.)
Bolt Supersessions
12201-B3090 12201-T0190 12308-18000 12309-18000 12309-71200
* A-series, E-series, H20
* possibly LD20, SD-series
bolt is 5mm longer
12309-21000 bolt M16x1.5x32 head hex 27mm
* L-series engine, Z-series, and newer engines
* Nissan Rogue, NV200
~15mm longer and smaller hex head
12309-V0800 280ZX Turbo

8084.jpgAlbum 8084 20601.jpgAlbum 20601 27103.jpgAlbum 27103 27104.jpgAlbum 27104

Woodruff Key

A woodruff key (also called a half-moon key) is a partial half-circle where the round part goes into the shaft and the flat length goes into the keyway of the pulley. As can be seen from the photos here, they are not exactly half the circle, but (like most automotive keys) are a bit less than half.

Fasteners — ALL A-series
12316-30000 KEY-WOODRUF 5x16 $1.98 (2023)
174_6571429bedb95.jpgPost 498098
two used, one for engine crankshaft pulley, one for lower timing gear
Buy at Bprojects
This key FITS: 
* All A-series engines
* J-series
* E1 engine (from Datsun 320)
Width: 15mm
Height: 6mm
Thickness: 4.8mm

NOTE: L16 key 00926-51600 5x16 Woodruff Key is not the same part number, but being 5x16 should be the same exact part. 926 is "semi-circular key"

  • L-series
  • VG-series
  • VQ-series
  • E-series
  • CA-series
  • etc.

174_657142b3b656c.jpgPost 498098 174_657142aa8d826.jpgPost 498098

5 x 15.7 x 6.5mm per DIN 6888
29069.jpgAlbum 29069

Underdrive Pulley

For high-RPM usage (above 8,000 RPM), move to a small diameter crankshaft pulley. This slows down the alternator and the water pump. Reducing the water pump flow is important to prevent cavitation at high speeds. And it also reduces friction, as faster spinning accessories take more power to drive.

Matsuoka 100/90mm twin-groove pulley (18mm spacing)
28581.jpgAlbum 28581

Note that this will not prevent overcharging, as the Voltage regulator does that (if the VR is not working correctly, the alternator may overcharge even at 1100 RPM). On the contrary, a slower spinning alternator is likely to undercharge until the revs come substantially above idle.

Nissan Competition Pulley Set

Nissan Competition sold two small diameter crankshaft pulleys, which runs the accessories slower, so is suited for extra high RPM usage. For normal street use, it may run the accessories to slow for reliable usage.

Small Diameter

    • Degreed to 40 degrees and has a diameter of 101mm/4.0". Can be used with stock alternator and w/p pulleys.

Extra-Small Diameter

The pulleys below must be used as a set and require the special belt (99996-H8020) due to their unique groove design.

    • Degreed to 45 degrees and has a diameter of 75mm/3.0"
  • 21051-H5720 WATER PUMP PULLEY
    • Pulley has a diameter of 100mm/3.9"
    • Pulley has a diameter of 90mm/3.5"
  • 99996-H8020 SPECIAL BELT

サニー A型ダブルクランクプーリー


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