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Combustion ChamberEdit

The combustion chamber is the area of the cylinder head where the intake port terminates and the exhaust port starts. It is also the area where the spark plug is located. There are three general designs of combustion chambers used in L-series cylinder heads.

Open ChamberEdit

The open chamber head has no quench area, but has a larger total volume (45.2 cc) than the other two designs. It is often used to reduce the static compression ratio of the engine. The lack of quench area though has the undesirable side effect of poor flame propagation which can aggravate knocking even while lowering the compression ratio.

Peanut ChamberEdit

The peanut chamber head, so called because of the peanut shape of the chamber, is often the prefered combustion chamber shape for high compression l-series motors. It has superior anti-knock characteristics from its increased quench area and is often used to raise the static compression of engines originally equiped with open chamber heads. The combustion chamber volume for these heads is typically about 41 cc.

Semi PeanutEdit

This is by far the least desirable of the three type of combustion chamber designs. The semi-peanut combustion chamber is commonly found on 210 casting cylinder heads from US market L-16 engines. It has less quench area than the true peanut chambered heads and less combustion chamber volume (aprox. 38.5) than either of the other two designs.

Spray BarEdit

An oil spray bar is used to supply additional lubrication to the camshaft. There are two common spray bars in use on L-Series Engines.

280zx spray barEdit

The 280zx spray bar is integral to the camshaft towers of the L28 engine. It draws its oil supply through the cam towers and will need to be shortened to be used on a 4 cylinder L-series engine.

Nismo spray barEdit

The Nismo spray bar mounts to the inside of the valve cover with two small mounting holes and a larger oil supply hole drilled on the passenger (right) side of the valve cover. It draws its oil pressure from a seperate line which is usually fed from a "T" fitting tapped into the oil pressure sensor port on the passenger side of the block. Most users of this type of spray bar report seeing a lower oil pressure at the oil pressure gauge, but it does not appear to affect engine operation in practice.


Open or closed found on many L-18 and L-20B's. The "domestic" version usually came with open chambers. Many of the "used Japanese import" engines came with the peanut version of this head. Large quantities of these used engines were imported in the 80's, so the peanut version is fairly common. These heads usually have 1.25" intake ports and square exhaust ports. 1.65" intake valves. Exhaust valves can be 1.38" or 1.30" W53 closed (with some exceptions) This head is from the Japanese market.

Some of these castings are for factory fuel injected engines and have notches in the intake ports to accommodate injectors. 1.25" intake ports and square exhaust ports. 1.65" intake valves and 1.38" exhaust valves.

U67 open The stock cylinder head for many L-20B's. 1.375" intake ports, square exhaust ports. 1.65" intake and 1.38" exhaust valves. U60 open Identical to the U67 head, this number has been found on very early L-20B's. It seems to be fairly rare.


The stock 'smog' cylinder head used on 1977 to 1979 620 trucks and 1980 720 truck with the L20B motor. Probably used also on similar year cars. Usually an open chamber design, but the W58 used on the 1979 200sx car, was a closed or P-nut chamber. Both, open or closed, had round exhaust ports with steel liners for burning off emissions. 1.375" intake ports.


Similar to the above W58 open chamber.


Used in L18 injected engine. See Datsun Silvia (S110) sold out U.S.A.


This is the factory casting that came on all US market L-16 motors. It was used on the L-13 motors in other markets. It has the smallest port and valve size of the L-series heads.


This is the original SSS head, as originally sold in non-north American markets. It has larger ports, larger valves and a smaller peanut-shaped combustion chamber.

The true SSS head from imported used engines or ordered from the Datsun competition catalog. Later versions could be ordered from the catalog with a V912 casting. 1.50" intake ports, square exhaust ports. 1.65" intake valves and 1.38" exhaust. These are hard to find. Any of the other closed chamber heads can be "converted' to this design by simply opening up the intake port to 1.50" (if that's desired) Some of these heads are marked "A87" on the side, but have "219" cast at the front of the head, just below the timing chain inspection plate.

The earliest version of the 219 casting as sold by Datsun Comp came with the 1.29 inch exhaust valves as well as the 1.65 intakes.. These where sold between 1970 and 1973 and then went to the 1.38 exhaust valve.. The SSS was an L4 version of the L6 in the early 240Z, and as such all internal parts where the same.

Just to clarify: L16 SSS 219 heads came with the 1.29 exhaust valves just like the 240Z for the stock 83mm bore of those engines, the 1.38 exhaust valves were used on L18 SSS engines and 219 heads..