Nissan L18 Engine: Everything You Need To Know

The Nissan L-series four-cylinder engine is an excellent replacement. These engines are less costly, are commonly accessible in both the United States and Australia, and are part of a bigger engine family than the Nissan A Engine. 

On the exterior, they are essentially similar from L13 to L18. Although the L20B 2-liter engine is a tall-block version, it may still fit under the hood without altering the sheetmetal. The Z-series Engine is similar, but includes a crossflow cylinder head that provides improved torque and fuel economy all-around. 

Finally, the KA engine, found in the Navara/D22 and USA S14, replaced the Z with a 16-valve head. These engines all have the same size and engine mounts.

What are Nissan L18 Engines? 

The Nissan / Datsun L18 is a straight-4, four-stroke gasoline engine with a 1.8 liter (1,770 cc, 108.01 cu in) carbureted displacement from the Nissan L-family. The Nissan L18 engine was manufactured from 1972 to 1976. 

The Nissan-Datsun L18 engine produces smooth, steady power thanks to OHC valves, a wedge-shaped combustion chamber, an aluminum cylinder head, and a completely balanced five-bearing crankshaft. Eight balancing weights are used in the L18 engine. The cylinder block is cast as a single piece with substantial skirting. The engine has a single, two-barrel, downdraft carburetor.

Engine Specifications and Design: 

  • Production Run: 1972 – 1976
  • Cylinder Head Material: Aluminum
  • Cylinder Block Material: Aluminum
  • Configuration: Inline 4
  • Bore: 85.0 mm
  • Stroke: 78.0 mm
  • Valvetrain: SOHC two valves per cylinder
  • Displacement: 1.8 L (1770 cc)
  • Compression Ratio: 8.5
  • Weight: 250 lbs.
  • Maximum HP: 103 HP at 6,000 RPM
  • Maximum Torque: 108 lb-ft at 3,600 RPM

Engine Design: 

The L18 engine with SU twin carburetor, known as the L18T, was also available. This engine had greater compression pistons, smaller combustion chambers, a higher compression ratio, and more power and torque. 

The L18 engine has a cylinder bore of 85.0 mm and a piston stroke of 78.0 mm, with a compression ratio of 8.5. It developed 103 horsepower at 6,000 rpm and 108 pound-feet of torque at 3,600 rpm.

Cylinder Block

The cylinder block of the Nissan L18 engine is made of cast iron. The five-bearing-support system is used in the cylinder block, which has a monoblock unique casting construction. 

Cooling jackets surround the cylinder bores, which are machined directly in the block. The oil ways in the block are configured so that the full-flow oil filter is immediately coupled to the block’s right side.

The crankshaft is forged from an unique steel. It produces smooth, steady power at high speeds when fully balanced. Oil injected via the main oil gallery and the oil holes that run parallel to the cylinder bores lubricates the main bearings.

The pistons are made of an unique aluminum alloy and feature two compression rings and one combined oil ring to limit thermal expansion. The piston pin is a hollow steel shaft with a specific shape. It is press-fit to the connecting rods and fully floating to the piston. The connecting rods are made of forged special steel.

Cylinder Head

The cylinder head is built of a lightweight and sturdy aluminum alloy with high cooling efficiency, and it has wedge-type combustion chambers. The intake valve has a specific aluminum bronze valve seat, while the exhaust valve has a heat resistant steel valve seat. All of these components are hot press-fitted. 

The camshaft is composed of unique cast iron and is housed under the rocker cover. The camshaft is supported by four aluminum alloy brackets. Camshaft bearings are lubricated via oil holes that feed to the cylinder head’s primary oil gallery. The cam mechanism directly activates a pivot type rocker arm in the valve system.

The dual-type valve springs are used in the Nissan L18 engine. The intake valves have a diameter of 42 mm and the exhaust valves have a diameter of 35 mm. The intake valve has a duration of 240° and a lift of 10.0 mm; the exhaust valve has a length of 248° and a lift of 10.5 mm. 

A double row roller chain powered by the crankshaft drives the camshaft. A chain tensioner, which is actuated by a spring and oil pressure, controls the tension of the chain.

Applications of Nissan L13 Engine: 

  • 1971 – 1976 Nissan Bluebird
  • 1971 – 1976 Datsun 180B
  • 1971 – 1977 Nissan 160B sedan (610)
  • 1973 Nissan Bluebird
  • 1973 Datsun 1600 SSS (P510)
  • 1973 Datsun 610
  • 1974 Datsun 620 truck
  • 1974 Datsun 710
  • 1979 – 1981 Datsun 180SX
  • 1980 – 1986 Datsun 720
  • Datsun 810

Engine Potential:

You’ll have a lot of trouble getting an L-series (2 or 2.2 liter) to produce 200 horsepower at the wheels; I don’t think it’s possible naturally aspirated. It’ll be prohibitively expensive, and the motor will be strung out like a taut rubber band on the verge of snapping. 

It won’t be terribly streetable, though, because it’ll probably overheat, have a terrible idle, and only run nicely at 6500 rpm. 13:1 compression ratio, fully ported heads, cam, valves, pistons, and rods. After that, everything will have to be massaged to perfection, and the engine will have to be driven constantly on race gas.

Due to the poor flowing heads, the L-series prefers to create all of their torque down low and then fizzle out as the RPM climbs. If you’re dead set on the L and have a lot of cash, get a longblock made by Rebello or another race engine shop, because that’s exactly what you’re looking for: a complete race motor. 

The L-series was a great engine in its day, and it’s still going strong now, but times have changed drastically. You’ll need to EFI it, use a standalone, perhaps construct your own manifold, and possibly rebuild it if you want to turbo it, and it’ll still be slower than a stock SR20DET in a 510.

The search for the perfect L turbo has been difficult, but that’s because there are a few out on the market. You know what they say: if you can’t beat ’em join em. 

Regardless of your decision-making process when it comes time to buying this part – which will be entirely dependent upon how much power and torque we want, make sure not only do I have all bases covered in terms or reliability as well as cost effectiveness; don’t forget about other factors such like longevity due from parts replacement too.

The twin carburetor system is not responsible for vapor lock as was previously thought – heat shields can be purchased but tuning them requires expertise which only few possess. This leads most owners feeling frustrated when trying get optimum performance from the car at times due in part due its antiquated design features like sync switching needles between carbs ;although there some who understand how.

You may opt not to go through the 510 learning curve stage, save some money and a lot of time by changing your engine right away. A VG, KA or SR appear popular alternatives but you could change anything you want into it! The engines indicated above will produce 200 HP at back wheels much simpler than an L series while driving just as well too.

Problems Surrounding Nissan L18 Engine: 

The Nissan L18 engines may be old, but they’re still a sought-after treasure. These durable workhorses will get you 500k trouble free miles if maintained properly and provide an excellent driving experience for years to come – even at 400+ horsepower.

Some consumers reported wide range of issues, however this was mainly due to, yes you guessed it – age, mileage, and overall condition.

Among the other concerns are:

1. Crankcase Ventilation Issues

There are reports from some owners that the crankcase ventilation tube pops out after the engine begins to idle and eventually dies out after a few minutes. Some of its manifestations include intermittent engine breakdown and engine dying out. 

It can also be caused by a bad ignition. 

2. Valve Cover Gasket Leaks

The oil is spilling from the valve cover vent hose. Because you have a Weber, it should be linked to the air filter. The block vent pipe or the hose connecting it to the PCV valve is broken or missing, and oil is leaking onto the header.

Summary

The Nissan L18 engine has a certain appeal to it that you can’t put your finger on. It’s not just nostalgia, there are other factors at play here and we need look no further than how long these cars last for before they become obsolete.

There seems like some kind of magical imperative involved as well: when one becomes old enough in age – at least 20 years, then this will happen – its powers over time seem limitless – unless something drastic happens first.

Japanese cars from the 1970s are much more sporty than before. The second reason is that they come with a lower price tag which means you can afford one! It’s also easy to find parts for them in case anything goes wrong on your own accord, making these vehicles super reliable and affordable too. 

And last but not least – Datsun engines were built like tanks, in terms of strength, so even if something does happen during usage it’ll probably be okay because there aren’t many competitors at this level. 

What the Datsun executives did under the sun for this engine is very remarkable. It’s amazing that how only a few people nowadays tune these kinds of journeys.

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