Tomei Oil Orifice

[krayton]

http://www.tomei-p.co.jp/_2003....html

so these lil things bring the oil gallerys down to 1.5 from the stock 2.0

supposdly to reduce over oiling the head and starving the bottom end.

last question on the other thread i had, was how many and why? do you install 2? or do you install 1 and block the other oil gallery.

fyi i read off the aussie boards that the stock is 2.0, the n1 block is 1.8, and then people install these which are obviously 1.5

[Stealth-Z]

I ran into what you are questioning a few weeks back. Here is a nice chart. Much of it has to do with what your intentions are with the car and the type of oil pump being used.

My RB30/26 head combo will be using the N1 oil pump with the 1.5mm restrictor. Also the rear orifice will be blocked off.

[krayton]

damn, suggests 1mm for my application w/ block off

nice lil pdf stealth. whered u get this from?

also what are u guys doing to block off the rear gallery?

[Stealth-Z]

The chart was on Skylines Australia.

As for what I am using to block it off? What ever my machinist recommends.

[Darius]

Please share that with us because I don't know the proper way this should be blocked off. I can think of a few ways to ghetto rig it though.

[98birdls1]

I'm still weary of blocking and using the restrictor. Hyrdualic lifters need oil to function, I worry about blocking it off so much as to where there isn't enough oil in the head to keep them functioning properly during normal/spirited driving.

My motor will mostly be for drag, I doubt I'll ever make it an autox event. So I won't be in high rev's for very long, I'm debating about leaving the back one unrestricted. OR use a restrictor in both. Wish there was some better research.

Luke

[Darius]

I'm going to look tonight but I'm assuming the hydraulic lifters are supplied via a passage that runs along the outside of each side of the head (between the valve lifters and exterior). The hole on the side of the lifter should point towards this oil passage to provide oil through to the top of the lifter to lube the cam lobe. This oil passage is pressurized so it should provide equal oil to all lifters especially under acceleration. With an N1 oil pump going in, I don't think I'll have to worry about a lack of oil in the lifters.

Someone correct me if I'm wrong, but I've been looking at this for a month or so and haven't found a reason why it wouldn't work.

[krayton]

http://www.skylinesaustralia.c...&st=0

so they say block the front one, and put the restrictor in the rear.

but for the circuit races they also suggest a bit more....

looks like a lot of work. still trying to find more info

[Joe]

what about using an accusump system guys?

[krayton]

what about using an accusump system guys?

http://www.livermoreperformanc....html

for people who havent seen it.

[Stealth-Z]

http://www.skylinesaustralia.c...&st=0

so they say block the front one, and put the restrictor in the rear.

but for the circuit races they also suggest a bit more....

looks like a lot of work. still trying to find more info

You sure it is not the rear one you want to block? I know for a fact the rear on the RB26 is blocked.

[krayton]

if u look at your pdf, the rb25s with vvt block off the front.

rb26s and rb20s do it the other way.

im not sure why. maybe cause of the vvt oil feed?

[Stealth-Z]

Sorry, did no know you had a RB25. Never dealt with them. The VVT adds a different dimension to them.

[Darius]

My question about that table was which RB25 are they referring to that doesn't have VVT? I thought all RB25DET's had VVT?

[jdmser]

The series 1 and 2 have VCT. I believe the Neo motor is the one with VVT. The VCT only control the timing of the intake cam, were VVT controls cam timing and lift of both cams.

[krayton]

My question about that table was which RB25 are they referring to that doesn't have VVT? I thought all RB25DET's had VVT?

i think they are referring to the NA rb25. since i believe some of those guys were using those with a rb30 build up

[Darius]

I'm having a few oil passage blockers made up at the machine shop. I'm having him match the dimensions of the Tomei orifice, but without the hole. If anybody is interested in one, let me know.

[themadscientist]

When I block passages I tap the hole and thread in pipe plugs. A friction fit cylinder of metal should be adequate though.

[Carl H]

When I block passages I tap the hole and thread in pipe plugs. A friction fit cylinder of metal should be adequate though.

which is an excelent idea incase you ever need to remove them, allen key plug is much easier to remove than one with smooth face and is pressed in...

[Darius]

Both ways sound like they will work for blocking the passage, and I was thinking that you could drill out the friction fit one if you ever wanted to remove it.

To clarify the table for the RB25DET, I believe it is the one with VVT (right column) so the front oil feed will be blocked and the rear feed will get the smaller orifice. I say this because all RB25DET's had the same NCVS system on the intake cam including the NEO.