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Discussion Starter · #1 ·
Im having a engine rebuild on a R32 GTR. Im wondering if any one has any comments regarding the Tomei - Oil Gallery Orifice and wether they are a good thing or bad thing. Description borrowed from the Nengun web site is :-

Orifice controls amount of flowing engine oil that is delivered to lubricate the parts in a cylinder head, and to cool down the engine body. However, stock oil-gallery orifice has given inadequate diameter so that too much oil is delivered to the cylinder head and problems listed below would occur.

(1) Too much blow-by Gas,
(2) Blowing engine oil,
(3) Leaking oil from valve guide,
(4) Insufficient oil delivery to the crank journal, (5) Miss-breathing air from oil pan under the horizontal G


Design of TOMEI oil gallery orifice is based on the experience of developing N1 endurance and drag racing engine. And by limiting diameter of orifice to diameter 1.5 (2.0 Normal), we succeeded in securing enough lubrication to the camshaft and valve while gaining amount of oil in the oil pan, and suppressing these problems. (To prevent blow by, we recommend using TOMEI 3D profile piston.)

- Combine with STD orifice to use
For RB25&20, ONLY solid type


So what do you guys think?
TIA
Kevin
 

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I have one in mine, as do many others. The RB26 does seems to dump a large amount of oil into the head, and this can cause big problems. There seems to be enough oil flow even with the restrictor, so probably a good mod especially for an upgraded engine/track use.

The only danger is the fact that a 1.5mm hole is more easily blocked than a 2mm one. It is the only source of oil to the head, so were it to become blocked, you can kiss your head goodbye. I guess this situation is rare though.
 

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Nismo made a restrictor that was even smaller, 1.2mm. Can't hurt to get one though I guess - they come free with a Tomei head gasket, $5 otherwise :p Anyways, you can see the difference between the stock 2mm and the Tomei just by eyeballing it.
 

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Discussion Starter · #4 ·
cheers guys, guess I'll play safe and have one fitted.
 

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Have it,no probs,so seems to work fine.
 
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