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[Datsun 1200 encyclopedia]

Crankshaft Pulley

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Category: Engine Mechanical

Datsun 1200 Crankshaft Pulleys came in single- and double-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. They may or may not have balancing holes drilled on the back side or on the front side. These are to ensure the pulley is balanced (the pulley is zero-balanced). NOTE that A-series engine are internally balanced, so all flywheels and crank pulleys interchange.

#Single-groove pulleys PULLEY-CRANKSHAFT
12303-18002 1966-1972 [Has multiple grooves for early cover]
12303-H1001 -8109 [Has single groove 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 
#Twin-belt pulleys (for factory Aircon)
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
#Triple-belt pulleys
12303-M7061 N10.A14.POWER-STEERING
12303-G5110 C22 A/C + Power Steering

#Single Belt early: triangular holes. Late: round holes
20598.jpgAlbum click to view 20602.jpgAlbum click to view

#Double-belt: Four kinds of front pulley: small, medium, large adjacent and & large skip
9764_4fbb295d6b146.jpgUpload click to view

20595.jpgAlbum click to view

Single-groove pulleys

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

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


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


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

* From 1972.02

15885.jpgAlbum click to view 20602.jpgAlbum click to view 20601.jpgAlbum click to view 8262.jpgAlbum click to view


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

120mm 600g

28572.jpgAlbum click to view 28573.jpgAlbum click to view

28576.jpgAlbum click to view 28577.jpgAlbum click to view

Twin-groove pulleys

dual-pulley/twin-groove/double sheave

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

G16 - Sunny Truck from 7908
Large center
Large/large sheaves
PULLY-1.jpg PULLY-2.jpg 20597.jpgAlbum click to view 28570.jpgAlbum click to view

Small center with puller holes
Large/small sheaves
28578.jpgAlbum click to view 20596.jpgAlbum click to view 20080.jpgAlbum click to view 28571.jpgAlbum click to view pulley_dual-1.jpg pulley_dual-2.jpg

Large/medium sheaves
25112.jpgAlbum click to view 28568.jpgAlbum click to view

Holey center
pu1.jpg pu2.jpg pu3.jpg

Triple-groove pulleys

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

Triple-Belt C22 with power steering
20595.jpgAlbum click to view 28569.jpgAlbum click to view


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


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.)

8084.jpgAlbum click to view 20601.jpgAlbum click to view 27103.jpgAlbum click to view 27104.jpgAlbum click to view

Woodruff Key

12316-30000_.jpg 12316-30000-.jpg

Fasteners -- ALL A-series
* 12316-30000 KEY-WOODRUF 5X16 - $1.13
  two used, one for engine crankshaft pulley, one for lower timing gear
  Buy at Bprojects
  key FITS: 
  * All A-series
  * J-series
  * E1 engine (from Datsun 320)
 Width: 15mm
 Height: 6mm
 Thickness: 4.8mm

Comparison: L16 key 00926-51600 5x16 Woodruff Key is NOT the same part number

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 click to view

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


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