Building a RB30

[1FSTKR]

Hi all,

just a few quick questions.

Im in the process of building me a RB30, with GTR head and T78. I have sorted out what rods to use but have no idea what forged pistons to use

Can anyone please give me some help with some part numbers or specification as to what forged pistons i should be using?

I appreciate all your help

thanks

[blk180]

i think u would find the answers in the sticklyed RB 30 thread up the top of this page

[drunkenmaster]

C'mon guys, someone must have done this conversion before :wassup:

[1FSTKR]

you refering to the thread with 82 odd pages.... dont think my boss would appreciate me too much if i was to read it all at work.

has anyone done this conversion before?

[GTR-Ben]

Do a search in that thread.. it has been discussed.

I am using stock pistons in my RB30 with GTR head.

[discopotato03]

1FSTKR it all depends on the intended use of the engine and the budget you have . If this thing is a flat out drag engine it could just about use the T78 . If you look at Garys (SydneyKid) posts it appears there are two levels of build .

1) 450 odd ATW HP: Std RB30E block crank rods pistons water pump and maybe

oil pump . RB30 water pumps are designed to move lots of water at relatively low revs , most are using RB26 pumps wich allow you to extend the rev range upwards without pump cavitation . The RB30 water pump is the cheapest new one but plenty of good 2nd hand RB26 ones around . All the R32 series and early R33 RB25 oil pumps fit the RB30 crank . I am using a good 2nd hand R32 RB26N1 pump , the only diff between this and std RB 26 is the relief valve spring tension . The RB30 is the only block without piston oil squirters - best solution is to ceramic coat your piston crowns . Using RB30E (NA) pistons with RB 4 valve heads gives around 8.2-8.3 CR , using RB30ET (Turbo) pistons from memory gives 6.8-7.0 CR .

4 valve heads are around 63-64cc chambers , the 2 valve heads were less and gave 9 and 7.8 CR .

For engines in this power range 8.5-9.0 CR makes the engine crisper , (more torque off boost and better drivability and fuel consumption at part throttle) . Some say they're achieving this by using Arias forged high top pistons , others are using JE VG30DETT pistons (larger 22mm insted of 21mm gudgeon pins and + 1.5mm or 87.5) decking the block around 1mm to get approx 8.6 CR . More can be had by more decking plus a smidge off the piston up to around 9.0 CR . It is VERY important to achieve 25-40 thou piston to head clearence to get effective squish or quench to lessen the chance of detonation . 25-30 thou is considered very good .

RB26 heads use larger diameter bolts so block holes to be re-drilled and tapped .

RB26 440cc injectors supposed to be good for 400-420hp .

Using cast Nissan pistons will require the timing and air fuel ratios be correct because if they are detonated they break ring lands .

2) The 900hp version needs good rods ie Carillo , better valves retainers springs cams rod bolts head fixings main cap studs and nuts and probably an O ringed block . I think all this is aimed at coping with higher rpms and power loads . Some are using 86.5mm pistons to leave a little more meat in the block . I have been advised not to use the RB26 N1 water pump as it is designed not to cavitate in constant high rev environments but does not move enough water at road speed revs to cool effectively .

This is only a brief overview and I think it is correct but you need to be sure so double check .

Hope this helps cheers A .

[discopotato03]

I forgot to add Nissan main crank bearings are up to the task but the big ends can suffer . Most seem to use Nissan mains and Nizmo big ends or all ACL race series bearings .

Again check this as I am no Swami Guru and get it wrong sometimes .

Cheers A .

[1FSTKR]

discopotato03 thanks for your advice