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[Datsun 1200 encyclopedia]

Japan Emissions

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Category: Emission Control And Tune-Up


Note 保安基準適合 means Safety Standards.



自動車排出ガス規制 automobile exhaust gas emissions regulations, the automobile of the internal combustion engine.

* 単体規制 Single Regulation (type regulation)
  applied to new models by the manufacturer 
* 車種規制 Vehicle Regulation
  constant regulation
1966 CO under 3%
1967 16-item inspection 
1969 CO under 2.5%
1970 CO inspection 5.5% idling
1972 CO inspection 4.5% idling
1973 testing
1974 NOx
1975 first sticker used

1976 sticker (Left: Used, Right: New with peeling cover)

排出ガス対策済 ステッカー, 排出ガス対策済, 般社団法人日本自動車工業会 (JAMA)


Nissan developed a stratified-charge cylinder head (a la CVCC) in 1973-1974. It was reportedly 2.1 liters, and from a photo looked like it might be an L-series engine. However in the end they were able to meet 1975 emissions standards by using NAPS instead.

Engine expected to meet U.S.-Japan smog rules

TOKYO - Nissan Motor Co., manufacturer of the Datsun automobile, Wednesday announced development of a low-pollution engine expected to meet Japanese and American auto-emission standards... Outgoing Nissan president Katsuju Kawamata admitted his company's NVCC technology might conflict with Honda's CVCC process it terms of patent right. But he said he would conferwith Honda to settle disputes that might arise.

Phoenix Arizona Republic October 25, 1973 pg A-10
Nissan Drops Engine Plans

Nissan Motor Co, Tokyo, Japan, said it has decided to suspend a commercial production plan of its "NVCC" (Nissan vortex-controlled combustion) engine.

Des Moines Register August 1, 1975 pg 17


S48 (1973) 昭和48年

First applies to B210 1973- (not B110 1970-1972)
* Sealed Fuel Tank with Flow Guide Valve for ventilation
* Flow Control Valve 14920-H5000 (mounts on #1 intake runner)
* Anti-diesel Valve (or Run-on Solenoid for A12T)
* Idle compensator in Air Cleaner
* Distributor D411-89


Exhaust gas countermeasures completed
anti-emissions devices of the ignition timing control system


"H" is the 1975 (50年度) emission standards. Also in 1975 in the United States similar regulations came into effect.


* H-B210 meets H-level emission standards
* H-B120 from 1975 uses NAPS-A engine A12
23894.jpgAlbum 23894

B210 EGR

All B211 (from December 1975) and VB210 (from October 1975) used EGR Exhaust Gas Reduction. This included Vans which were not fitted with catalytic converters.

B210 Catalyst

Nissan system's of exhaust gas cleaning by catalyzed oxidation (NAPS) adopted. A 2-way catalytic converter converted carbon monoxide (CO) and unburned hydrocarbons (HC) to produce "harmless" carbon dioxide (CO2) and water (H2O). It was only later than CO2 was acknowledged to be a pollutant itself. NOTE: In 1980 the 3-way converter introduced a 3rd reaction to reduce the third major pollutant NOx.

To enable efficient conversion, extra oxygen is introduced into the exhaust system by use of Nissan A.I.S. (Air Injection System), using a passive air induction (tuned pulse-flow) system. It used a cylinder head with an air passage drilled from front to back.

23097.jpgAlbum 23097

No feedback was used to control the fuel system. A carefully tuned carburetor was sufficient to meet the 1975 emissions target.

* JAPAN B211 A12.S,K 7512-
* JAPAN HB211 A14.S,K 7512-
* JAPAN GB211 L16 7602- (51 year standard)
* not used on Van

Because the very hot converter is located under the passenger seat:

  • a temperature warning system is fitted
  • seat mounting is modified. 1976-1977 Passenger seat clears the bulge in the floor

Exhaust Temp warning lamp on dash 排気温度警告灯ランプ排気温度警告灯ランプ

Relay#25230-89915 floor sensor relay

Seat for converter-equipped B211
28710.jpgAlbum 28710

Unleaded Fuel

無鉛 Unleaded petrol only

14807-89910 STICKER-FUEL 7510-
* placed on assistant's window
Buy at Bprojects
無鉛  無鉛ガソリンを
14806-89901 LABEL-UNLEADED FUEL ONLY 8910-
* placed inside fuel door
触媒 無鉛に限る Catalyst - Limited to Unleaded


1976 regulation including NOx

Applied to the 1200 October 1975

* Automatic Choke to reduce emissions during startup


"E" 1978 emission standard (Showa 53 Year) 53年度排出ガス規制適合車

1200 Choke Warning

* Choke warning lamp added to Dash#Late April 1978
 レエン、ワーニング ランプ (アート チヨーク レンズ)
  LENS-WARNING LAMP 24250-H2500 (Auto Choke Lens)

The dash 'Auto Choke' looks like a blank plate for the choke cable knob hole. Does it actually light up?

Brown mid-model dash
27038.jpgAlbum 27038 174_5d65ee6af3492.jpgPost 492391

Grey late dash
27181.jpgAlbum 27181

1200 EGR

* EGR comes to the 1200 for NOx reduction. See EGR#1200


L - 1981 regulations was the reason for the B122 model change.

23169.jpgAlbum 23169

Spark Delay

1200 EGR with VVT

EGR refined with a VVT valve

Main: EGR#1200


R - 昭和63 1988 regulations were applied to the late B122 (R-B122) which arrived in 1989 October.

25511.jpgAlbum 25511

* placed under bonnet
Buy at Bprojects
26019.jpgAlbum 26019

1200 Catalyst

  • NOx reduction via 3-way Catalytic Converter. A carburetor with mixture control (ECU-controlled carb + Oxygen Sensor) is used to make the converter more efficient by keeping the mixture close to 14.7:1
  • Exhaust Temp warning lamp on dash 排気温度警告灯ランプ排気温度警告灯ランプ
  • Electronic Ignition to keep the tune longer (thus limiting emissions)

Oxygen Sensor on the 95W Exhaust Manifold
manifold-late.jpg 95W1.jpg

Temp Sensor on converter Exhaust_Piping#Converter
27041.jpgAlbum 27041 27181.jpgAlbum 27181

Exhaust Temperature 'EXH TEMP' warning lamp on Dash#Late
27036.jpgAlbum 27036 27037.jpgAlbum 27037 

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