F-cam for NB8C (later model Sr-2) BP VVT Mazda MX-5 Miata

Duration Lift HLA Base diameter
IN252° 10.8mm Special lifter needed 33mm
EX256° 10.0mm Special lifter needed 33mm

F-cam Intake New Version VVT for Solid for NB8C (with VVT)

F-cam Exhaust New Version for Solid For NB8C (without VVT)

Solid lifter set (16 pieces/set)

Cap shim

From 2.65 to 3.65 mm there is a set up every 0.05mm.
For one lifter you need 16 pieces.

Thanks to the controlled oil pressure the variable valve timing actuator (cam pulley on the Intake manifold side) and the phase of the camshaft on the intake side change continuously and we can get a suitable valve timing at any operating state.

The oil circulated from the engine block reaches the cam pulley through the oil orifice at the tip of the camshaft while being controlled by the oil control valve (OCV/solenoid valve)

When removing the oil, the oil pressure switch on the oil cartridge side is being diverged.
Through the pipe we can send oil to the cam easily.

The oil orifice at the camshaft’s tip is a 2-way type (makes the cam timing advance or retard).
The valve timing becomes suitable by pouring oil from two ways by OCV and by controlling the advance and retard continuously.

As mentioned above at the tip of the camshaft an oil orifice has been installed and at the cam tail a ring that makes the sensor pick up the cam position with accuracy has been set up.

Through the cam tip’s oil hole the oil can get to the variable pulley.
The protuberance of the tail ring becomes the trigger of the pulse.
Thanks to it the cam’s position can be determined.

The special metal mold and new processing are the reasons for a higher cam price.

Furthermore while repeating the advance and the lag we tested the genuine cam on engine bench and chassis dynamo tester and after getting all the data, we managed to set up an effective high cam.

Usually it doesn’t slide this easily when you try to turn it manually.
This is a picture taken after removing the fixed pin that is locked by a spring.
When the oil pressure arises the pin gets pushed back and the lock is lifted. After this, the pulley changes according to the ECU controlled oil pressure.

Tests on the engine bench and chassis dynamo.
We spent a lot of time on developing this cam for the variable valve.

The newly released camshaft is the first in the case of Miata/Mx-5 with adjustable variable valve timing.

The lift on the intake side is 10.8mm and it contributes to the improvement of torque power.
The 10.8 mm lift can respond to the genuine valve spring, that’s why it’s easy to set it up.
There is not even need for head undercut.
Furthermore, the clearance of the valve/piston that is in the variable range is very easy and you don’t have to worry about meddling.
While securing the lift amount, the base circle is being squeezed to 33mm and set with a special lifter and cap shim.
(It is the same method as in the case of NB8 early models) The cam’s tip doesn’t meddle with the lifter hall’s brim.
It is a type with no modification and its installation is easy.

The F-cam can be used together with a genuine ECU.
The sales point of the F-cam is the stable idling and a good feeling of acceleration.
Furthermore, it becomes a more effective item used together with full computer controls like Freedom or 4-throttle injection systems.

For further information feel free to consult us.


Maruha Motors Co., Ltd.
Ushizuma 2095-6, Aoi-Ward
421- 2106 Shizuoka city, Shizuoka prefecture
TEL: 0081-54-294-0076
FAX: 0081-54-294-1312
E-mail: info@maruhamotors.co.jp