Starting a Derelict L24 Engine

Over the years, several CZCC members have produced write-ups on the topic of bringing an L24 engine back to life after a long period of storage.  I think this one was the best of the lot, with credit to its Canadian author Phil _ (aka 'Blue', aka '240260280', aka 'Hoover').  I believe that this write-up originally appeared on the 'Atlantic Z-Car' website (still a great resource for how-to articles), but as of 2024 it seems to have disappeared.

STARTING A DERELICT NISSAN L24-SERIES ENGINE –   Author:  'Blue'

Lubrication

·        Take the oil spray bar off and blast all of the holes with the straw of a can of carb cleaner. Spray into each hole then spray into the larger holes where the oil flows in from the cam towers. Do this until the bar is flowing clean solvent. Tilting the bar and flowing down helps.

·        Change the oil and pour extra oil over the valve train. Soak it good!

·        You should probably prime the oil pump. An easy way is to feed a clear vinyl hose into the oil passage behind the oil filter and run the line as far forward in the oil galley as you can. Connect a tight fitting funnel to the open end then hold high and pour oil into the funnel and let it drain into the hose (with the end now above the oil pump).

·        Remove plugs and turn the motor over by hand from the crank to ensure it is not seized.

Electrical

·        If happy, hook up a remote starter and crank motor from passenger fender with valve cover off. Watch for oil coming out of the oiling bar. Make sure all holes are drizzling oil. It may take a while so make sure you have a good battery. You may have to prime pump more if oil does not come out after ~ 1 minute

Spark

·        Once you have oil, check for spark and inspect the electrical system. You should have 12V at the coil when the key is turned to either ‘START’ or ‘ON’. Replacing plugs, distributor cap, and points is a good step, but if you have spark at the plugs, just change them to NGK's for now.

Cooling

·        Drain radiator and flush engine with water and drain a few times.

·        You should change the rad hoses and interior heater hoses and water pump as soon as you can but it is not needed to start. Also look at the hose fittings when you pull off the hoses as they corrode to nothing. You should change the thermostat now.

Fuel

·        Remove air cleaner from carbs (both cover, filter, and back plate)

·        Remove fuel hoses from fuel rail to fuel bowls, and from fuel rail to fuel pump

·        Remove carb bowl covers and make sure the needle valves are working. More carb cleaner will help. Make sure, though, that the needle valves do not have rubber tips (these types may swell up from solvent exposure)

·        Remove carb domes and clean with solvent (no abrasive). Keep front dome with front carb. Drain the oil in the plunger region.

·        Carefully remove piston and needle and clean. Again, no abrasive and be careful not to bend the needle. Keep front piston with front carb.

·        Clean carb body

·        Remove the small hose between the fuel bowl and jet on each carb and make sure they are not collapsed or filled with tar. Replace if required.

·        Unscrew the choke lifting arm from each jet and remove each jet. Use proper fitting screw driver and press in firmly when turning.

·        Clean each jet with carb cleaner (inside passage and outside).  Scrub the brass tube’s outer surface with a Scotch-brite pad until it shines.

·        Clean the passage in the carb body where each jet fits. Test-fit each jet in its passage and make sure it can slide up and down with no binding.

·        Turn the knurled knob under each carb all the way up until it stops. You may need to spray some penetrating oil on these from below to get them loose. You can turn them up and down to work loose. Some carbs have a safety stop underneath that you can remove for the moment

·        Once the knurled knob turns freely and you have turned it all the way up, turn back down 2.5 turns. Use the big bump on the knob to measure turns. You may have to feel for it.

·        Reinstall the safety stop and leave ~ ¼” to ½” between it and the knurled knob.

·        Reinstall the jet and connect the choke rod to it. However, disconnect the choke cables for the moment. Make sure the jets lift all the way up. When you look into both carb bodies the tops of the jets should be seen to be the same distance down in the tube ~ 2.5mm (one turn = 1mm, so 2.5 turns) if you measure the depth.

·        Reinstall the pistons and needles in their proper carb body.

·        Reinstall dome (w/o plunger) while carefully lifting and dropping the piston with the finger of your other hand in the front carb hole. The piston should drop all the way to the bridge with no binding. Try to tighten all 4(or all 3) screws evenly, rather than just 1 at a time. In order to remove piston binding, you may also have to twist the dome CW or CCW as you tighten the screws.

·        Install plungers but no oil.

·        Clean fuel bowls

·        Install new hoses from fuel bowls to jet. Make sure they don't kink.

·        Install fuel bowl lids.

·        Remove hoses to fuel rail and clean the fuel rail by spraying carb cleaner through it. Spray into both delivery and return holes. (Note: The small return line has a fixed orifice at the end and this must not be clogged).

·        Install new hose from fuel pump to fuel rail.

·        Install new fuel filter

·        Install new hose from fuel filter to fuel pump

·        Run two 6' fuel lines from fuel filter (delivery/output) and from fuel rail (return) into a gas-filled jerry can sitting next to passenger wheel.

·        With plugs out, crank the motor to drive fuel pump and send fuel to fuel bowls. Check for fuel in bowls.  Check for no leaks in hoses.  Check for no fuel bowl overflows.

Start

·        You are now ready to test start!

·        Install plugs and have fun.

·        Do a valve adjustment after it heats up.

·        Measure compression to get an idea of how well it is sealing.

·        After it’s run for a while, fill the carb damper tubes with 20W oil (3-in-1 oil in blue container also works fine)

·        Forget about using car’s own gas tank until you remove it and clean it.  It is probably very rusty and varnished inside. You will be left on the side of the road if you try to use the tank.  Also: Replace the flex hoses (and clamps) between the tank and hard lines.  While you’re doing this, splice an in-line disposable fuel filter into the supply-side hose.