Rb25/30 Rb30det Vvt Internal Oil Control

[fletch rb30]

the head oil gallery you are feeding it from has 2 direct feeds from the oil filter.

[urtwhistle]

Hi Jason, did you ever pull that ball bearing thing out? I'm about to tackle this converson on my car also. stupidly i have always assumed that Neo heads were the same as the VVT R33 heads. ooooops

Regards

Chris

[The Mafia]

I've done this, but the car won't be on the road for a month or two yet.

I'll you you all know how I go.

[Dorifta]

I han't done a Neo head.. but I'm guessing that Nissan didn't stray too far from what they already know works.

Please take another pic, up close and front on, just like mine so everybody can see what your looking at.

Top work on the mod. Im about to embark on this procees, Where did u get the replacement plug, Did u press it back on or hammer

Thanks

[fletch rb30]

I have had a look at the neo head and it has a bearing feed running off the head gallery and a seperate feed just for the vvt.

You wont be able to pull the plug out and drill it like the r33 head.

Im appears the vvt solenoid blocks the oil pressure when the vvt is off and when engaged, it pressurises the vvt solenoid. when disengaged the oil pressure bleeds back through the solenoid instead of the constant loss

[boost is good]

I have had a look at the neo head and it has a bearing feed running off the head gallery and a seperate feed just for the vvt.

You wont be able to pull the plug out and drill it like the r33 head.

Im appears the vvt solenoid blocks the oil pressure when the vvt is off and when engaged, it pressurises the vvt solenoid. when disengaged the oil pressure bleeds back through the solenoid instead of the constant loss

just doing the conversion atm.. looking at drilling through the bucket gallery into the vct gallery between the first cam journal and first lifter bore then plugging the entry point back up.. anyone know what the original neo oil restrictor size is for the vct.. I only have a head thanks

[boost is good]

drilled and plugged .. just putting it all together now then in the car to see how it goes.. have pics but cant post em up

[JonnoHR31]

www.photobucket.com

[jarrod83]

Tried this mod whilst doing my rb30 conversion, worked great, was very simple and tidy

drilled out the oil returns in the head and ran a rear head oil drain kit but decided not to restrict or block the oil feeds in the block, but i seem to be losing a hell of a lot of oil still from the breathers. . . i was wondering if anyone has considered drilling out the 1.5mm oil in the brass plug to 2mm, in theory i would think the head would still have enough pressure to engage the vct but also drain more oil when the vct is off in the higher revv range

has anyone tried this? or think it may work?

Cheers

Jarrod

[T04GTR]

thats a cool mod, but why didnt nissan use this mod?

[JonnoHR31]

going to be doing this shortly for my 30det. theres plenty of info around on restrictor sizes with or without vct, but all the info for vct heads include an external oil feed. what size restrictors would work best with this internal feed on a street driven 30det? i ordered a couple off the net and got sent 1x 1.5mm and 1 blocked, worried it might not be enough oil for normal driving?

[The Mafia]

I left the factory restrictors in since I am already robbing oil for the VCT.

Drilled the oil returns too.

WIll post up how it goes.

[JonnoHR31]

factory 30 or factory 25 sizes?

[The Mafia]

good point. Whatever was there - I'd assume the RB30 restrictors then.

Wonder what size they are?

[dkshauno]

I'm building a 25/30 combo but don't want to use the VCT, is it better to have the solenoid off or on?

I'll be doing this mod but only to supply the front cam tunnel with oil.

Has anyone got any info on not using the VCT?

cheers shaun.

[JonnoHR31]

good point. Whatever was there - I'd assume the RB30 restrictors then.

Wonder what size they are?

2mm i think. factory 25 are 1.5mm i think.

i ended going with 2 ~1.6mm feeds, works out a little less than factory 25 by my calculations which should stop any blow by without starving the head

[jarrod83]

Johnno let us know how your engine goes, i think the rb30s have two 1.8mm standard, with leaving them standard i was still getting way too much oil to the head.. a bit of spirited driving would result in quite alot of oil coming out of the breathers... i think im going to 2x1.3mm this time

Jarrod

[jarrod83]

Forgot to mention, thats with a rear head oil drain and all of oil drains drilled out in the head only, and the two factory rear oil drains dremeled out a bit, as well as the smaller restrictors im going to try and stick a descent sized hose from my catch can to the sump to allow both oil to return and the blowby from the engine to escape without clogging up the oil returns in the head

Jarrod

[JonnoHR31]

does anyone have any pics of exactly where to drill out the oil drains in the head?

now you have me wondering if i should make them smaller than 1.5mm, are the standard 25 feed definately 3x1.5mm? because i wasnt getting much blowby at all with the 25 so i figure aslong as i keep it less than standard 25 it should be fine

Edited August 8, 2010 by JonnoHR31

[jarrod83]

With regards to the oil restrictors in the rb25 standard, im not 100% sure to tell you the truth, i have heard conflicting sizes, most people say the two feeds are 1.5mm, but when comparing them to the size of my 1.5mm tomei restrictor they look slightly smaller, i have heard of ppl measuring them up to be 1.3mm, the vct feed i have heard it being anywhere from 1.5-1.9mm =/, when my engine is apart ill measure whats in there now

As for the oil returns, you can see at the bottom of the block what holes go through to drain into the sump, so just follow them through to the head and youll know what to drill.. from memory im pretty sure all the small oil return holes are on the exhaust side, im going to attempt to get the two large holes at the back of the head drilled out more, i know a drifter that claims he drills them out a fair bit.. i only dremeled them up abit as i was afraid of hitting anything important.. ill let you know what gets done, but it wont be until i get my engine pulled back apart next holidays

Jarrod