Tomei Oil Galley Orifice / Restrictor - RB20 RB25 RB26 RB30

Tomei 191071 Oil Galley Orifice / Restrictor - RB20 RB25 RB26 RB30

The Orifice controls the amount of oil flow that is delivered to the head to lubricate the parts in the cylinder head and to cool down the engine assembly. However the stock oil-gallery orifice has a hole that is too large which allows too much oil to be delivered to the cylinder head which will cause the problems as listed below. 

(1) Too much blow-by Gas,

(2) Blowing engine oil,

(3) Leaking oil through the valve guides,

(4) Insufficient oil delivery to the crank journal,

(5) Allows air pockets into the system from when the oil pan is under horizontal G-Forces. 

The TOMEI oil gallery orifice was designed from the experience and data we had obtained from the development of our N1 endurance and drag racing engines. By restricting the diameter of the orifice to ?1.5mm (Normal is ?2.0mm) we succeeded in securing enough lubrication to the camshaft and valve while maintaining the correct amount of oil in the oil pan which resolved the common problems. (For added Blow by prevention, we recommend using the TOMEI 3D Profile pistons.)