RB30 Questions

[CrayZ]

So i just got in contact with "RIPS" and i got a quote for a 600 hp RB30 right at around 10 grand. This sounds doable but i cant help but think i could get it done for cheaper.. i have a buddy with a rb25det second gen for 1500 lying around and this comes with everything i need tranny wiring etc. why not just buy the block and start swapping what needs to be swapped?

 

again i am pretty new to the rb30's is it as easy as slapping a 25 head on a 30 block upgrading fuel and turbo and poof 600 hp? im sure it's not but how close is it?

[synthtk]

From what I understand the RB25 head will go on it but needs a bit of work to make the water/oil passages to line up, an RB26 head pretty much slaps right on but you need to either make sleeves and use RB25 head studs or tap the block for the larger 26 head studs.

 

You would also want to change the rods/pistons because the compression ratio would be way low with just the RB30 bottom end stock (I believe).

 

You also need to get a special timing belt and setup the tensioners differently than how they are stock, some people use a modified tensioner/idler pully setup and others use a twin tensioner setup.

 

Here is a good place to start looking for info, also Skylines AU has quite a bit of info. http://meggala.com/RB30head.htm , http://users.on.net/~sandr/twincam.htm and http://paulr33.skylinesaustralia.com/docs/RB30_DOHC.pdf

 

The hardest thing seems to be finding a piston that will yield a decent compression ratio. Places like SPOOL will sell you Arias or CP Pistons but they might be a custom spec.. RIPS can also provide the pistons you need, as well as the belt, tensioner setup and everything else ya may want if ya wanted to build it stateside.

[rrcredline]

I have done the RB25/RB30 (for a non turbo RB30DE) conversion myself at home using the R33 RB25DE head. Used the RB25DE pistons which gave me 10:1 compression

The easiest head to use is the R32 Skyline RB25 non vvt version. Perfect water gallery alignment BUT slightly smaller intake ports.

The R33 RB25 VVT head only has a minor front water gallery mis-alignment but is so minor most people here in NZ don't worry about it. This head has the bigger intake ports and VVT for slightly better performance.

I modded my slightly at the water gallery in any case...

http://www4.wave.co.nz/~lakewood/Skyline/R33_head.htm

 

The RB26DETT head is the ultimate head to use but for most its to damn expensive to use. This could be the head RIPS is quoting. Also his price will offer very reliable 600hp. Not sure its as easy as just popping a RB25 head on and getting 600hp without a whole lot else than upgrading the fuel and turbo and having it reliable..

 

Nigel

[wax]

if you use the n/a rb30 pistons you will end up at about 8.3:1 this is what i am doing

 

The std rod bolts on an rb30 are bigger than arp 25 bolts so they will be fine the con-rods are massive so you will be fine there.

Really all the bottom needs is a good honest rebuild and away you go.I am using the rb26 head as the triple throttle bodies are way cool and i like the solid lifters as well.

[Careless]

RB30 rods are similar to the W-Series VG30 rods.

Infact, I think they're the exact same dimensions, and also use the same bearings.

 

Not sure what an ARP 25 bolt is, but sizing on the rod bolts is not all that matters.

The ARP2000 rod bolt is much stronger than any nissan rod bolt of that era.

 

Infact, to tell someone to re-use nissan rod bolts is a bad idea. Or even use stock nissan rod bolts for 600hp. The RB25 coughs up rods and pistons at 600+ whp with stock rod bolts.

 

DONT DO IT.

 

Rods can be had for 650+ shipping, and come balanced to within a gram, have brass bushings pressed in, are two-piece cross-grain die forgings, and come with ARP2000 or ARP L19 bolts if you choose.

 

The standard con-rods also weight more than the stronger and better built forged H-Beam and I-Beam counterparts.

 

Consider the X-Beam pauter rods if you're looking for light/strong ratio higher than that of any other rod.

 

Wax, the RB26 uses individual throttle bodies, not 3 throttle bodies. Each pair is grouped, but it's still 6.

[wax]

yeah ok i should have six but it comes off as three

Im using the stock rods and bolts as alot of people here in australia do and are making over 400hp at the rear wheels doing it , thats enough for me

You cant buy arp rod bolts for rb30 rods but i believe you may be able to for the vg rods. Im not sure on that one

[fraz]

yeah ok i should have six but it comes off as three

Im using the stock rods and bolts as alot of people here in australia do and are making over 400hp at the rear wheels doing it , thats enough for me

You cant buy arp rod bolts for rb30 rods but i believe you may be able to for the vg rods. Im not sure on that one

 

 

You need 1 and a half sets of sr20 rod bolts to fit the rb30 stock rods. arp part number 202-6005

 

You can also use vg30 arp bolts but you need to mod the rod a little. I havent seen it done but i think you just have to bore the bolt hole out a fraction.

 

Stock rods and pistons are ok if your expectations are reasonable. Im making 400rwhp on 18psi with stock r33vvt head. My mate is making 450rwhp on a stock r33vvt head. Both motors are stock bottom end, just a hone/head skim, new rings and acl bearings. 550cc injectors, china greddy copy plenum

[fraz]

I have done the RB25/RB30 (for a non turbo RB30DE) conversion myself at home using the R33 RB25DE head. Used the RB25DE pistons which gave me 10:1 compression

The easiest head to use is the R32 Skyline RB25 non vvt version. Perfect water gallery alignment BUT slightly smaller intake ports.

The R33 RB25 VVT head only has a minor front water gallery mis-alignment but is so minor most people here in NZ don't worry about it. This head has the bigger intake ports and VVT for slightly better performance.

I modded my slightly at the water gallery in any case...

http://www4.wave.co.nz/~lakewood/Skyline/R33_head.htm

 

 

Nigel

 

Nice job on the block weld. We did it on our first rb30, but since then, its easier to weld the head then get it skimmed. It is necessary to do as there is only 1mm of head covering the gasket in some places.

Its a 5 min job to get it welded. Just get the stock rb30e gasket, or rb26dett gasket and hold it up to the head and you will see what needs welding.

 

 

There is also a thread on skylines australia in the rb30 section about feeding the r33 vvt from the internal head oil gallery. eliminating the need for the external feed to the head.

 

 

The r34 rb25det neo head is a superior head. The r33 greddy copy front facing plenum bolts up and the head has solid lifters. Also the vvt setup is far better as it is not a constant loss system like the r33 and dumps way less oil into the head when the vvt is not in use

Edited February 13, 2010 by fraz
spelling

[fraz]

From what I understand the RB25 head will go on it but needs a bit of work to make the water/oil passages to line up, an RB26 head pretty much slaps right on but you need to either make sleeves and use RB25 head studs or tap the block for the larger 26 head studs.

 

 

 

You also need to get a special timing belt and setup the tensioners differently than how they are stock, some people use a modified tensioner/idler pully setup and others use a twin tensioner setup.

 

 

You can run the rb25 head bolts or studs in the rb30 block with the 26 head. You need the right washers under the bolts/nuts and thats it. You have to mod the block slightly to take the 2x rb26 head dowels. Any machine shop could do it in a few mins.

 

 

You can run 2x tensioners, then you can move them both and adjust your total cam timing easily. Also, tensioners are cheaper than idlers!

All the information you need is in the skylines australia rb30 section

[kiwi303]

http://www.driftweblog.com/2009/03/rb30-guide-1.html

 

theres 6 or 7 parts to this series.