Description

Nissan L20A, L24 Service Manual – What You Need on the Workbench

I have watched guys hang a head gasket because they trusted a third-party torque chart off a forum. That is a four-hour job turned into a new head. If you are working on an L20A or L24 engine, you need the actual factory data, not someone’s guess. This Nissan L20A, L24 Service Manual is the exact publication that Nissan issued to its dealer techs. 190 pages of specs that were verified on the assembly line. No abbreviations left to interpretation. No wire colors that fade into guesswork. Open it, and you get the same information that the factory put on the test bench.

Engine General Coverage and Main Specs

Section EG starts with an external view of the L24 engine showing the SU carburetor setup. That matters because a vacuum leak on those carbs can fool you into chasing a fuel problem. Main specifications live on page EG-4 – bore, stroke, displacement, compression ratio. Vehicle reference data tells you which engine went into which chassis. If you do not know whether your car has the L20A or L24, the unit serial number location is right there in Section EG-6. You also get the recommended lubricants, gasoline, and coolant on EG-5. I have seen coolant types swapped on these engines and cause heater core corrosion. The manual calls for specific ethylene-glycol formulations. Use what is written.

7 Systems Covered: From Tune-Up to Emission Control

The Quick Reference Index lists nine sections, but seven are actual vehicle systems: Engine General, Engine Tune-Up, Engine Mechanical, Engine Lubrication, Cooling, Fuel, and Engine Electrical. Emission Control gets its own section (EC). Each section is indexed to the factory part numbers you will find in the DATSUN 240Z and 2000 parts catalogs. That means no aftermarket interchange confusion. Need the proper ignition timing procedure? Section ET. A compression test spec? Section EM. This manual treats each system as a separate job. You do not flip through overlapping chapters hoping to find the data.

What Torque Values Are Listed in the Manual?

Torque is where most shortcuts fail. The manual lists main bearing cap torque, connecting rod nut torque, cylinder head bolt torque sequence and values. These numbers are not the same for every L-series build. The L20A and L24 have different head bolt specs because of the bore size and gasket design. If you are assembling a short block, you need the exact values from this manual. Page EG-4 gives the base specs, but the torque procedures are spread across the mechanical and tune-up sections. I always lay out the torque page next to the work. You will not find a generic range like “50-60 ft-lbs.” The manual gives one number. That is what the factory wanted.

Cooling System and Fuel System: Factory Procedures

Section CO covers the cooling system – thermostat location, water pump disassembly, hose routing. These old Nissans are prone to air locks if you do not follow the refill procedure. The manual tells you to open the bleeder on the thermostat housing. Section EF handles the fuel system, including the mechanical fuel pump and carburetor adjustments. Float level, idle mixture screw turns, throttle linkage. If you are rebuilding the SU carburetors, the specification for the dashpot oil is in there. I rebuild those carbs with the manual open to the float height page. It keeps you from bending the float arms by guess.

Get the Electrical System Right the First Time

Section EE is the engine electrical system – starter, alternator, ignition coil, distributor. Wiring colors are printed as they left the harness plant. No “black with trace” that someone adapted. The manual shows the exact routing for the L20A and L24 engine harnesses. If you have a no-start condition, the diagnostic flow starts with ignition coil resistance checks. Specs are given in ohms at 68°F. Do not trust your multimeter reading against a generic number. Use the factory value. I had a customer’s L24 that would crank but not fire. Coil resistance was 0.3 ohms above spec. New coil fixed it. The manual had that spec on the electrical section page. Saved four hours of chasing.

Source Authenticity: OEM vs. Aftermarket Documentation

This is a factory-issued Service Manual, printed by Nissan Motor Co., Ltd. in Tokyo. The part number is 99999-20015. Aftermarket reprints often miss the factory bulletins that updated torque values or carburetor settings. The foreword specifically tells you to check the SERVICE JOURNAL and SERVICE DATA AND SPECIFICATIONS for the latest revisions. That is the kind of detail you do not get from a CD-ROM sold at the parts counter. If you want to keep your L20A or L24 reliable, use the source that the factory wrote. This is not a Chilton or Haynes condensation. It is the full 190 pages of engineering data. Pair it with the Nissan L20A, L24 Service Manual – Factory Specs for Engine Overhaul for a complete engine rebuild reference. For other Nissan models, the Nissan Xterra 2005 Service Manual – OEM Factory Spec and Nissan 60 1967 Service Manual – Original Factory Bulletin are also available with real factory data. For an overview of how OEM manuals differ from generic ones, you can read the Automotive Industry Overview and also see Automotive Industry Overview.

Frequently Asked Questions

Does this manual cover the L20A and L24 engines only?

Yes. It covers only the L20A and L24 series engines. It does not include L28 or later engine data. If you need L28 data, look for the specific L28 service manual.

Can I use this for a Datsun 240Z with an L24?

Absolutely. The manual references the DATSUN 240Z Sports Service Manual and the 2000 Service Manual. This engine section works with those chassis manuals to give you the complete picture.

How many pages is it?

190 pages.

Are the torque specs in imperial units?

The main specifications are given in ft-lb. The manual also lists metric equivalents, but the primary values are in the unit system used by the original factory. I always work in ft-lb on these engines and the manual gives those directly.

You have spent enough time guessing on an L-series engine. The factory put the answers on paper. Access the Factory Manual and keep it within arm’s reach of your toolbox. When the bolt has to be at exactly 58 ft-lb, the manual tells you. When the carb float height is 0.472 inches, the manual tells you. Do not waste another Saturday on a mistake that the factory already solved.