Has anyone succesfully used an rb25 vvt head on an rb30 block with an external oil feed? I know it can be done, Keen to know if someone beat me to it...

Do you mean, where they tap the feed into a T piece on the oil sender outlet, so you can retain the oil pressure sender and also feed the VVT? Mick

Have a look around on the skylines downunder forums. I think it may be covered over there in a bit of detail. Might be wrong though Some original photos have not been recovered yet.

Yeah I'm fairly sure its been done. I just think people avoid it and take the easier more convenient option.

can sum1 post up some pics of the RB25DET ,RB25DE,and RB25 VVT if theres turbo also and can they label which is which please. Some original photos have not been recovered yet.

http://www.rbforums.com/specsEnginesRb25s.php Sorry about the Errors on the sides, I'll get them fixed up asap.

Quote: Originally Posted by bextor84 Yeah I'm fairly sure its been done. I just think people avoid it and take the easier more convenient option. whats that?

Getting the other head that lines up with the rb30 oil galleries. I'm fairly sure thats why..

onnce past the basic mods, the VVT usually is disabled anyway. i woudltn worry about it.

can sum1 show me the difference on the head by looks or somthin??

I'm doin' this now! The RB25 head needs to be welded at the front left to give enough metal to seal the water gallery on the RB30 block and the oil gallery drilled, tapped and a grub screw put in. I had a 1/8" BSP (i think) brass fitting drilled and tapped into the gallery with a 1/4" bundy tube fitting on the other end. I'll get some pics and post 'em later.

External VCT feed...... Some original photos have not been recovered yet.

Out of interests sake what oil pump did you decide to use on your motor MonstaS4? Looks as though you managed to use the RB25 dipstick too, did the old one pull out of the block easily or was it a bitch? Mick

I bought a complete R33 RB25DE and used it's oil pump but used a washer under the pressure bypass valve spring to give it more preload. Hopefully this will give slightly more oil pressure. The dipstick took about 30 secs to punch out from underneath. Some original photos have not been recovered yet.

Sounds sweet. Buying the complete motor is the way to go as well, makes life 10x easier, having access to all required parts in front of you. Mick

Quote: Originally Posted by MADDNEZ onnce past the basic mods, the VVT usually is disabled anyway. i woudltn worry about it. Have you done this Maddnez? Unless you're putting in lumpier cams, why would you disable it? The lumpy cams will then make it idle rough and be fairly rough down low in order to gain HP up top. VCT is the best of both. The low overlap at idle and low revs will make the car smooth as silk down low but will still have plenty of stomp up high. For a daily driver, i know what i'd prefer.

The VCT on the RB25's was mainly designed for emissions and economy, thats why it is disabled in a lot of cases. I guess with an aftermarket ecu you could use one of the outputs on the ecu to trigger the solenoid at a specific RPM to give a performance gain. ill see if i can find a link to the discussion about the VCT and exactly how it operates as nissan inteded it, in no way a performance measure.

Quote: Originally Posted by MonstaS4 External VCT feed...... just asking wat is the 2 prong plug there??? i dont think i have that on my RB25DET head???? im sure i dont and can u take a pic 4 me str8 on showing both cam gears and all if its possible thankz man Some original photos have not been recovered yet.

87calais: So how about getting cams specificly to gain performance out of the vct? I think the same thing occured with the M3: Early 90's model M3 had more aggressive cams, single VCT, where as the later models have less agressive cams and twin VCT. The later models have far more power though, abiet the weight factor increasing.

Hybrid VL, The 2 prong plug is the VCT solenoid. This varies the inlet cam timing by 20 degrees, duration is 240. The advanced timing (solenoid on) is inlet opens 20 BTDC, closes 40 ABDC. The retarded timing (solenoid off) is, inlet opens at 0 TDC, closes 60 ABDC. The cam is retarded at idle for just about zero overlap, it is fully advanced at around 1,500 RPM, and again fully retarded above around 4,200 RPM. These timings give a low RPM torque boost of around 5% on the RB25DET, probably 20 - 40Nm on the RB30DET at a guess. In the process of sourcing a timing belt atm. Probably use a Gates with 2 tensioners in the lower positions. Some original photos have not been recovered yet.