Description

Nissan A10, A12 1971 Service Manual – Factory Spec for the A-Series Engine

If you are working on one of these old A-series engines, you know the frustration of trying to find correct data. Backyard blogs and aftermarket reprints get the torque sequence wrong, or they skip a step. That is how head gaskets fail. This Nissan A10, A12 1971 Service Manual is the original factory document from Nissan Motor Co., Ltd., Tokyo. 163 pages, published in 1971, revised February 1971 (P/N 99999-20020). It covers the A10 and A12 engines exactly as they left the assembly line. I have used this manual on the job, and it saved me from guessing which main cap bolts go where.

Engine General: Specifications You Can Trust

Turn to page 2 for the Quick Reference Index. You will see sections labeled EG, ET, EN, EL, CO, EF, EC, EE, SE. Each one stands for a major system. Page 4 gives you the Engine General chapter with main specifications. Here you find the recommended lubricants, coolant type, and even the unit serial number location. If you are doing a periodical inspection on an A10 or A12 engine, the checkpoints are on EG-6. This is not a generic list—it is the same inspection sequence that Nissan techs followed in the 70s.

Does This Manual Cover Fuel and Electrical Systems?

Yes. The Fuel System section (EF) covers carburetor adjustments, fuel pump specs, and emission control tie-ins. The Engine Electrical System (EE) gives you the complete wiring for the ignition, starter, and alternator. Electrical troubleshooting without the factory diagram means chasing shorts by guess. With this manual, you trace the circuit by the schematic that matched the harness from the factory. The Cooling system section (CO) lists the thermostat opening temperature and radiator capacity in quarts—imperial units, as delivered.

8 Sections for Complete Engine Overhaul

The manual breaks the work into eight dedicated sections plus Service Equipment (SE). Engine Mechanical (EN) gives you the head removal sequence, piston ring gaps, and bearing clearances. Engine Lubrication System (EL) covers oil pump disassembly and pressure specs. Engine Tune-Up (ET) includes valve lash settings, ignition timing, and compression test data. Each section has step-by-step repair procedures. You get the torque values—no need to hunt for a third-party spec sheet that might be off by 10 ft-lbs.

Understand the Wiring Before You Touch It

I recommend studying the Engine Electrical System (EE) section first. If you are converting points to electronic ignition or replacing a harness, the schematic on page [DATA NEEDED] shows the exact wire colors and connector locations. Do not skip this. I have seen too many barn-find restorations where someone fried the alternator because they guessed the polarity. The manual also includes the 1971 emission control system (EC) for the A10 and A12—useful if you need to pass a visual smog inspection in a region that still checks classic cars.

That is the difference between a job done right and a tow truck call.

Cooling System: Factory Flow Rate and Capacity

Cooling system maintenance on these engines is critical. The CO section specifies the coolant capacity in quarts (imperial) and the thermostat rating. Overheating destroys A-series heads. The manual gives the correct fan belt tension and water pump inspection points. If you are replacing the radiator, you need the original flow direction and hose routing from this manual—aftermarket radiators sometimes flip the inlet/outlet.

Original OEM Document, Not a Reproduction

This is a scanned copy of the actual Nissan service manual, not a reproduction or a compilation from third parties. The file name is Nissan_A10-A12_1971_Service_Manual_en-22809001948.pdf. You get 163 pages of the original factory print, including the foreword on page 3 that explains how to use the manual in conjunction with the Datsun 1200 chassis manual. Every torque specification, every clearance value, and every wiring diagram is exactly what Nissan published in 1971. I have compared this PDF against a used paper copy I own, and it matches page for page. That matters when you are torquing a connecting rod bolt to the factory spec—if the aftermarket manual says 30 ft-lbs and the OEM says 36, you follow the OEM or the rod cap walks. If you want background on automotive manufacturing standards, check the Automotive Industry Overview Automotive Industry Overview for context. But for A10 and A12 engines, this manual is the definitive source. Do not trust a photocopy from a forum that may have cropped off the torque value column.

Related manuals you might need alongside this one: NISSAN A10 A12 Service Manual (the same), Nissan Xterra 2005 Service Manual – OEM Factory Spec if you work on newer engines, and Nissan 60 1967 Service Manual – Original Factory Bulletin for even older models.

What torque specs are listed in this manual?

Each section lists the factory torque for that component. The Engine Mechanical chapter (EN) includes head bolts (specified in ft-lbs with sequence), main bearing cap bolts, connecting rod bolts, and flywheel bolts. The Engine Tune-Up section gives you valve lash adjustment specs and the correct spark plug gap. The Fuel System section covers carburetor mounting nuts and manifold bolts. All values are in foot-pounds per the original JIS standard. There is also a tightening sequence diagram for the cylinder head—critical to prevent warping. You do not need to hunt for a separate spec sheet; it is all in the manual. The cooling system also lists hose clamp torque, if you want to be thorough.

Can I use this on a Datsun 1200?

Yes, the A12 engine was used in the Datsun 1200.

For DIY owners and shop mechanics, this manual belongs on your workbench. The original 1971 factory data eliminates guesswork. Stop fighting with parts store diagrams that miss the 1971-specific emission controls. Automotive Industry Overview may give you background, but the actual step-by-step procedures are in this manual. Access the Factory Manual now and get the torque data, wiring diagrams, and tune-up specs that Nissan intended.