Crankshaft pulley
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.
Overview
pulley1200
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
#Double-belt: Four kinds of front pulley: small, medium, large adjacent and & large skip
Sizes
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
180
Type 180 Single Belt triangular holes- Pre-1972 (multiple timing marks) 650g
H10
Type H10 Single Belt round holes - Post-1972 (single timing mark) 740g
* From 1972.02
H85
Type H85 used by Sunny Truck A12. Looks similar to #H10 but with a slightly larger hub/smaller triangular holes
120mm 600g
B140
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Twin-groove pulleys
dual-pulley/twin-groove/double sheave/W-pulley (for aircon use)
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
Unknown application A-series H-pulley (skip groove)
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Small W Pulley
Small center with puller holes
Large/small sheaves
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
Pulley has the usual single timing mark to match the 1972-up Timing Cover
Large W Pulley
Large/medium sheaves
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
X-large W Pulley
G16 129mm - Sunny Truck from 7908
Large center
Large/large sheaves
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
#Triple-belt pulleys 12303-M7061 N10.A14.POWER-STEERING 12303-G5110 C22 A/C + Power Steering
Part Numbers
Buy at Bprojects
Pulleys
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)
B310 * 12303-H1001 same as B110 * 12303-H1002 * 12303-H8500 single pulley * 12303-H8501 * 12303-H8900 dual pulley * 12303-H8905 dual pulley
Pulley Bolt
The crankhaft pulley bolt uses a special conical washer.
http://datsun1200.com/uploads/photos/31418.jpg
12308-H1000ᴳ WASHER-PULLEY BOLT 1 A12 - $1.29 12309-78200ᴳ 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 12309-21000ᴳ bolt M16x1.5x32 head hex 27mm * L-series engine, Z-series, and newer engines * Nissan Rogue, NV200 ~15mm longer and smaller hex head 12309-V0800ᴳ 280ZX Turbo
Woodruff Key
A woodruff keyᵂ (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 12316-30000ᴳ KEY-WOODRUF 5x16 $1.98 (2023) 
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 00926-51600ᴳ 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.
5 x 15.7 x 6.5mm per DIN 6888ᴳ
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)
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 too slow for reliable usage.
Small Diameter
- 99996-H1160 SMALL DIAMETER CRANK PULLEY
- 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.
- 12302-H5720 [Extra] SMALL DIAMETER CRANK PULLEY
- 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"
- 23151-A9960 ALTERNATOR PULLEY
- Pulley has a diameter of 90mm/3.5"
- 99996-H8020 SPECIAL BELT
TS pulley set
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