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Hey guys,

I'm back with another tutorial that I made (thanks to isolation). This is on a how to swap the RB25 bottom end to a RB30 bottom end with a 25 head in a R34 (R33s and R32 should be kinda similar i think) that I did last year. I had to split the tutorial into 3 parts (each part is like 15mins). It starts with preping the RB30 block, to taking out the RB25, and then putting in the RB30/25 and starting it.

The reason why I did an RB30 swap was not because of an upgrade but because my RB25 was showing up bad results on the comp tests and there were cheap RB30s going around (I actually made money out of selling parts from the RB30 that I didn't need lol). The goal for this car is only to be a daily responsive streeter on pump fuel (won't ever take it to the track). 

It's my first time ever doing something like this (I had no help, did this on my own), so take it as a guide line. If I were to do this again, I would definitely use a proper engine crane and take the whole engine out including the gearbox next time, but yeah... this was a real poor mans job and it got the job done and I've been driving this RB30/25DET Neo everyday to and from work as my daily and I've never had a problem with it (have been clocking 5000+ Kms on it as of 10/4/2020). 


Here's the videos:

Part 1:

Part 2:

Part 3:

I'm really happy with the outcome. Considering I knew nothing about RBs or any engine before I bought this R34. I learnt everything from researching (a shit load) on these forums, so thanks SAU, here's me giving back. 

The car ended up making 323.8 HP on the dyno with my OP6 highflow turbo which is a bit too small for this engine. So I will go with a bigger one in the near future.

List of mods on my car previously that I brought over to the RB30 swap:

  • HyperGear G2 RB25DET OP6 highflow turbo with ballbearing
  • 3" turbo back exhaust
  • 100mm thick FMIC
  • Splitfire coil packs
  • Xspurt 525cc injectors
  • Nistune ECU
  • Z32 AFM
  • Walbro 255lph fuel pump (hard wire mod) 98RON
  • Exedy HD clutch
  • External oil cooler
  • Koyorad all aluminum radiator


Just something to add here on the side if anyone was interested (kinda like a build page, but I might as well put it here). This was my whole budget explained:

So the total amount that I spent on this build/recon/swap was $3415.

I bought a complete RB30 engine (without the box) for $150. Apparently this engine was used in a TAFE course for mechanic students to practise timing stuff on, so the pisons had heaps of screw driver marks on. A recon was in the picture anyways because I want this engine to last for ages. So I only wanted to keep the block, crank and rods. I sold everything els (head, alternator, ecu ect) for $240. That's already a profit of $90 lol! The reconditioning of the RB30 block and RB25 head was the most expensive out of the whole budget costing $1420.

The recon from Harris Engines in Perth:

  • $400 - Bore and torque plate hone
  • $190 - Face block
  • $180 - Machine and fit crank collar
  • $90 - Acid bath
  • $90 - Face/deck RB25 head
  • $50 - Acid bath head
  • $90 - Face flywheel
  • $150 - Fitment of pistons to rods
  • $180 - Balance rotating assembly

All other things:

  • $270 - 1mm oversized Hypatec RB30ET set of pistons + Hastings Rings
  • $253.45 - RB25 ARP Head stud kit (202-4301) from wolf racing
  • $261.25 - RB25DET Neo genuine nissan gasket kit
  • $106.49 - RB30 ACL race main STD bearing set 
  • $88 - RB30 ACL race conrod STD bearing set
  • $30 - RB30 small end rod bushes/bearing set
  • $99 - RB crank collar from Lewis Engines
  • $38.75 - RB oil restrictors (one 1.5mm and one blank one)
  • $38 - RB30 brass welsh plugs
  • $13.71 - RB spigot bush
  • $38.98 - RB genuine nissan timing belt fastner kit
  • $41.5 - genuine nissan thermostat
  • $78.14 - Genuine nissan R34 pull type thrust bearing
  • $110.5 - Genuine nissan RB25 exhaust manifold fastner kit
  • $43.2 - Dayco 94407 (T866) timing belt
  • $72.11 - Mamba RB30/25 turbo water braided line kit
  • $81.59 - Braided -4AN hose + fittings for the external VTC feed from Enzed
  • $330 - Dyno tuned car by C-Red in Perth

All of the labour except for the recon and tuning was done by me. 

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Hey mate just watched all your vids. I spent hours looking for a decent writeup and this beat all my expectations. I'm slowly making preparations to do exactly the same thing, thanks for the inspiration and help!

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