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[Datsun 1200 encyclopedia]

Water pump

From Datsun 1200 Club

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Category: Cooling System

Datsun 1200 used a traditional vane-type water pump, driven by the fan belt. The same pump was used from 1966 Datsun B10 to some 1982 Datsun B310 up through 1994 Nissan 1200 Sunny Truck. However, air conditioning-equipped models used a different hi-performance pump.

See also: Heater Motor Fan



Datsun 1200 style long-nose pump:
20402.jpgAlbum 20402

Heavy-duty (short-nose) H72 pump. Can be interchanged with long pump if used with matching short-nose spacer, pulley and fan.
10737.jpgAlbum 10737

If you use regular water in the engine, it will look like this:
21296.jpgAlbum 21296
Use coolant/antifreeze to to prevent the rust. NOTE: This is mild oxidation, and has not damaged the pump.

Paraut-brand pump


There are two basic water pumps for A-series engines, each of which uses a different pulley and fan. 11095.jpgAlbum 11095

NOTE: Both setups are exactly the same length block-to-fan, so they interchangeable as a set along with the pump.

Long-nose VS short-nose pumps
5681a.jpgAlbum click to view

1. Short pump with short pulley, spacer and high offset fan
20400.jpgAlbum 20400

2. Long pump with long pulley and low-offset fan
20435.jpgAlbum 20435

You can't mix and match these parts, as the short pump uses a different bolt pattern (the spacer is an adapter allowing the fan to bolt up).

  • Datsun 1200 is long shaft, large pulley (spins slower)
  • Newer is short shaft with spacer, small pully (spins faster)
  • Note that the pulley bolts are wider apart in the newer pump
  • Newer pump has studs for the spacer
  • Some aftermarkets pumps have a sheet-metal impeller, smaller but more agressive
  • Genuine Hitachi and Atsugi pumps (both A12 and A15) have a cast iron impeller

Cast iron vs. stamped steel impellers. Cast iron shaped impeller is superior at high RPM.
174_659ceddcb15a4.jpgalt:[ 5681 498161]

Datsun 210

The heavy duty H72 water pump was installed on all 210s (North American B310) starting with 1980 model year vehicles (late September 1979 production).

from engine serial number A14-433246-B  
* HLB310-693967
* KHLB310-563501
* WHLB310-047416
from engine serial number A15-028246
* KPLB310-201907
* WPLB310-021027 
from engine serial number A12A-112069
* LB310-0211047
* LB310-044592

Factory Air Conditioning

NOTE: Dealer-installed Aircon may have any sort of fan, pump and pulley. For example, 1200s may be fitted with flex fan or metal fan (neither of which are Nissan parts).

Factory A/C used the H72 style (short-nose) water pump, with either a fixed-blade fan or clutch-fan.


Datsun 1200 pickup (B120) used the H72 aircon water pump & pulley, but with a fixed-blade fan:

21060-N0110 FAN 7804-8109 <0,0> 21060-G1210 [330 mm ?]
21060-G1210 FAN 8110-
21064-G1660 SPACER-FAN 7804-7907 <0,0> 21064-G1615
21064-G1615 SPACER-FAN 7908-
21051-H7200 PULLEY
21010-H7225 WATER PUMP 7804-8109 <0,0> 21010-H7227
21010-H7227 WATER PUMP 8110-
11720-H7200 BELT 7804-8109 L=970
11720-H7201 BELT 8110- L=990


B310 Air Conditioning (also 1977-1978 B210.A14)
26418.jpgAlbum 26418

Matched set: Water pump, pulley, fan and clutch

Part Numbers

* Standard Duty (type 180) long nose
* Heavy Duty    (type H72) short nose
  used on most factory A/C models (starting 1977)
  used on all 210s (A/C and non-AC starting 1980)
B110 Water Pump Part Numbers
21010-18003 (BA010-M6626) ASSY-PUMP WATER B110 $45.67
21010-18026 ASSY-PUMP WATER WITH GASKET -0770 rebuildable
21010-18027 ASSY-PUMP WATER WITH GASKET 0870- > 21010-18026
21010-H1025 ASSY-PUMP WATER WITH GASKET 0971-1072 (1972 model year) 
* interchages with <> 21010-H18027
* 08120-62010 BOLT-HEX FIXING FAN (4)
* 21069-21000 WASHER-COCK FIXING FAN [bend-tab lock strip]
Gasket (new and old style use same gasket)
* 21014-H1001 GASKET-WATER PUMP USD $4.13
* fits A10, A12, A13, A14, A15, A12A
* Beck/Arnley 1310366 $34 Short type
10737.jpgAlbum 10737
21010-H5025 (BA010-M6626) ASSY-PUMP WATER WITH GASKET 1172- $45.67 USD
* Used through 1982 model years B110, B210, B310
* Bosch 96005 with 1.970" fan pulley bolt pattern.
B210, B310 OPTIONAL Aircon A14 From 0876
  From 0876 Optional A14 $57.17
* Bosch 96024 with 2.362" pulley bolt pattern


Casting marks
* Hitachi 13 long (smooth shaft): TO
* Atsugi 13 short (ribbed shaft): X11
Datsun 1200 Pump vs Short Pump
* pulley flange bolt centers:            1.970" vs 2.370"
* pulley flange diameter:                 2.42" vs 2.95"
* pulley flange center locating hub:      0.85" vs 1.24"
* Height of flange outer face from block: 2.38" vs 1.98"


Datsun 1200 uses a tough plastic 4-blade fan of 310 mm diameter (12.2 inch). 330mm fan was Datsun 1200 OPTION FOR TROPICAL USE.

Main: Fan


USA dealer option flex-fan
842.jpgAlbum 842


These are the common pulleys:
- Datsun B110: 129 mm (~5.05") diameter, 2.33" high, locating hub 0.85"
- Datsun B310: 107 mm (~4.21") diameter, 1.74" high, locating hub 1.98"

Use a matched set of pulley and water pump. Both sets end up the same distance from the radiator.

1. Long pump with long pulley and low-offset fan
20435.jpgAlbum 20435

2. Short pump with short pulley, spacer and high offset fan
20400.jpgAlbum 20400

These are not mix-and-match parts, as the short pump uses a different bolt pattern (the spacer is an adapter allowing the fan to bolt up).

16639.jpgAlbum 16639
The long pump (B110) uses a fan with positive offset. The short pump (B310) uses a fan with negative offset, but with a spacer. The overall height of fan from block face is the same for both models.

21051-18000 PULLEY-FAN & WATER PUMP 
* Original Style: 1.970 inch bolt centers
* A10, A12, A13, A14, A12A
* B10, B110
* B210 (with spacer)
* B310 to 0779 (with spacer)
11720-18002 BELT-FAN L=838 [For B110]

B310 North America pulley (for short nose pump, use with spacer):

* New style: 2.362 inch bolt centers. 
* Spacer has 1.970 holes on the fan end
* B310 from 0879  
* A12A, A14, A15
11720-H9910 BELT-FAN(987) A12A Cal From 0879 [For B310]
* replaced 11720-77701 BELT-FAN(980)
26417.jpgAlbum 26417

The two combos of pump/fan/spacer interchange as a whole combo. The newer type allows the fan to be unbolted while the radiator is still in the car.

Presumably the A-series moved to a small diameter pulley to slow down pumping flow, perhaps to prevent cavitation at high speeds.

A third pulley is the B310 Aircon setup:

21051-H7200 PULLEY-FAN & WATER PUMP (D=103)
* B310
* OPTION A14,A15, JAP.A12,A13 
* No spacer, but instead a clutch 
* 7-blade fan (350 mm)
11721-H7210 BELT-FAN(970)(FOR AIR-CON)

A fourth pulley is:

21051-H8500 (appears to fit long-nose pump, with no spacer)
smaller diameter than the 180 type pulley?
* B120 8910-
* B310 JAPAN.(A14S.S,K+A14E) -7909
* B310 JAPAN.A14S.S,K.MT 7910-

Billet Pulley
Custom made
16997.jpgAlbum 16997 16996.jpgAlbum 16996 16995.jpgAlbum 16995 16991.jpgAlbum 16991

28579.jpgAlbum 28579 28580.jpgAlbum 28580


Main: Fan belt


Leaking? Time to replace the pump
23591.jpgAlbum 23591

After unbolting
23594.jpgAlbum 23594

Clean the gasket surfaces carefully. Remove all traces of prior gasket
23595.jpgAlbum 23595

Use the thin paper gasket, and torque the bolts to spec. It should not be very tight, these are small bolts.


1200 water pumps made after August 1970 are non-serviceable.

Up to July 1970, a kit was made to repair the pump
26753.jpgAlbum 26753

Early Datsun B10 pumps were rebuildable. Seal and seat with gasket.

Electric Water Pump

Water Pump delete cover plate
14312.jpgAlbum 14312 23394.jpgAlbum click to view 13419_545ca00e231ca.jpgPost 461016

Datsun 1200 spec is 12 liter/minute @ 5 meters. Outlet is 1 inch inside diameter. It requires the maximum flow at peak HP, so it depends on how much HP you will build in, and the radiator size/efficiency.

23203.jpgAlbum 23203

For drag racing, you can turn off the pump while accelerating. For street use, an electric water pump decreases the reliability (because the standard mechanical pump is virtually 100% reliable).

lamb_daiquiri: I've got an 80lpm Davies Craig pump on my A15 with a pump controller. Most of the time it just pulses (when I can hear it). The controller replaces the thermostat for regulating coolant flow by adjusting pump speed based on a temperature sensor. Once up to temperature I don't see the needle move at all. Don't ever run the pump dry, they have ceramic seals in them that don't like to be run dry.

I've also got a electric fan switched off a 70C thermo switch mounted on the radiator outlet. Comes on when it needs to.

cp4678800517011537614.jpg 24818.jpgAlbum 24818 

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