RB25DET NEO into R33 Conversion

[inmaniac]

Hey all.

Been a very long time since I posted here but I wanted to share some info in case it is useful. I've learnt so much on SAU so I need to pay it back!

I recently blew the motor in my R33 - not sure what happened, maybe just age and stress, but it exploded the piston and rod in cylinder 5 very good. In the process it also bent a valve and caused some other damage. In my situation, I decided I would just hunt down a long motor and swap it in. I managed to find a NEO motor for a good price and decided to have a crack. It turned out to be pretty straightforward and runs great.

 
The old motor. I didn't place the rod like this, when I took off the sump it greeted me

 
NEO waiting to go in
 

There's been a bit of discussion that I've found in a few threads in this forum about what you need to do to get a NEO motor into an R33, and specifically if you were going to use the R33 (in my case a series 2) intake and exhaust manifolds. I'm going to list here what I did to get this to work. Hint: it wasn't much.
 

HERE IS WHAT I DID TO GET A NEO MOTOR IN MY R33 USING THE INTAKE AND EXHAUST FROM A SERIES 2 MOTOR:

• You must swap the VCT Solenoid plug to the "New Nissan" style. I got mine from EFI Solutions here.
   
  Old plug won't fit the NEO solenoid
  
   
  New plug was straightforward to wire. Pro tip: make sure you get the right crimp tool (you need one that does non insulated crimps)
   
• You need to swap the CAS wiring if you have the old style metal-cased CAS. (I was lucky, as I have a 40th anniversary R33, my CAS is the same as the NEO CAS, so no change needed). My understanding is the wiring is reversed, but check yourself.
• I used all accessories from the S2 motor. All brackets fit without modification.
• I used the S2 Harmonic Balancer, as it has a 2-rib design which matches the power steering pump pulley from the S2
• I swapped the entire intake. 
  • On the head there are 2 studs for the intake manifold, 1 on either end, to mount the intake along with the bolts. I used the S2 studs as they match the manifold. The ones in the NEO weren't long enough.
  • I was informed that the NEO head has smaller ports. When I did a direct comparison, the difference was basically negligible, and the intake gasket part number is the same between S2 and NEO, so it can't be that different. Nonetheless I did some very slight porting with a die grinder and I haven't noticed an issue.
• I swapped the exhaust manifold, turbo, etc and it was a direct swap.
• I added NEO Splitfire Coilpacks - these mount differently than S2 so I couldn't reuse my originals ones, in the NEO they mount directly to the head and not via brackets as seen in the S2.
• I used my S2 flywheel but they are the same as NEO
• I swapped to my S2 valve and valley covers, they were a direct swap. This wasn't a must-have.
• I used the timing belt cover and back plate from the S2 motor
  • On the NEO, the timing belt back plate has a hose that you don't need. Although not a must-do, I swapped to my S2 back plate and cover.
• I used the S2 thermostat housing
  • The NEO housing is a smaller diameter and overall different dimensions. You could use it find but would need to find the right hose. I simply swapped to S2 and it was bolt on.
• All cooling and vacuum hoses swapped over without modification
• Added S2 engine mount brackets
  • These are the same as NEO but new motor didn't come with them.

 

I think this is everything really. There honestly wasn't much to it, when I got everything plumbed it fired up without issue and without touching tune. The biggest change for me was a VCT plug which was nothing, then it was just little bits to make sure it all goes together nicely. As for the end result, you can see a comparison below along with some pics. I did all of this in my driveway basically solo  

 

 
Old motor, RB25DET S2, 238xxx kms. ARP Studs, Cometic HG, Kelford Springs, Hypergear G3 21U, E85 - 300.4 rwkw
 

 
New motor, RB25DET NEO, 250xxx kms, ARP studs, Hypergear G3 21U, E85 - 310.8 rwkw
 

 
It wasn't fun in a cold a dusty driveway covered by bunnings gazebos
 

 
New motor coming together. New water pump, pulleys and belt
 

 
Motor in the car

 

I hope this provides some useful info and helps some of you.

Cheers.

Josh.

 

 

Edited July 3, 2021 by inmaniac
Formatting

[discopotato03]

Congrats on having a go and it being a success .

These are a few things to note if you ever decide to run the Neo inlet manifold and electrics .

The idle air control valve housing is totally different and it's solenoid uses a different plug . Work around is to get one from early N14 Pulsars , or the NA Neos solenoid which use the R33 type loom plug .

Other PITA is if you want to mount the R33's TB/TPS on the Neo turbos plenum - so you can fit up the R33s J pipe and plug in the native TPS . The Neo's bolt pattern is the same but the R33's mount flange is differently shaped so you can't just slap the 33's TB on the Neo plenum . To make it work simply make up a sandwich plate cut to the R33s shape . I was given an old 33 plenum so I cut the TB mount flange off and machined the back flat/square in a lathe .  

Thanks for the heads up on the crank pulley , I didn't know they were different .

I don't have the finances to do a Neo motor yet but I will do the Neo inlet manifold in the not too distant future . 

Cheers A .

 

 

[Dylank]

Nice write up mate. Collected some good info from all this

😁👌

[Dylank]

Out of curiosity what mods have you got to produce the power out put

[GTSBoy]

On 11/8/2023 at 12:19 PM, Dylank said:

Out of curiosity what mods have you got to produce the power out put

It would be the turbo, and injectors & management required to fuel it.

A fuel pump would be required, and a FMIC would be expected - you wouldn't get there on the stocker. Turbo back exhaust, ditto.

No mods would be required to the engine.

[Stealth82]

On 03/07/2021 at 1:03 PM, inmaniac said:

Hey all.

Been a very long time since I posted here but I wanted to share some info in case it is useful. I've learnt so much on SAU so I need to pay it back!

I recently blew the motor in my R33 - not sure what happened, maybe just age and stress, but it exploded the piston and rod in cylinder 5 very good. In the process it also bent a valve and caused some other damage. In my situation, I decided I would just hunt down a long motor and swap it in. I managed to find a NEO motor for a good price and decided to have a crack. It turned out to be pretty straightforward and runs great.

 
The old motor. I didn't place the rod like this, when I took off the sump it greeted me

 
NEO waiting to go in
 

There's been a bit of discussion that I've found in a few threads in this forum about what you need to do to get a NEO motor into an R33, and specifically if you were going to use the R33 (in my case a series 2) intake and exhaust manifolds. I'm going to list here what I did to get this to work. Hint: it wasn't much.
 

HERE IS WHAT I DID TO GET A NEO MOTOR IN MY R33 USING THE INTAKE AND EXHAUST FROM A SERIES 2 MOTOR:

• You must swap the VCT Solenoid plug to the "New Nissan" style. I got mine from EFI Solutions here.
   
  Old plug won't fit the NEO solenoid
  
   
  New plug was straightforward to wire. Pro tip: make sure you get the right crimp tool (you need one that does non insulated crimps)
   
• You need to swap the CAS wiring if you have the old style metal-cased CAS. (I was lucky, as I have a 40th anniversary R33, my CAS is the same as the NEO CAS, so no change needed). My understanding is the wiring is reversed, but check yourself.
• I used all accessories from the S2 motor. All brackets fit without modification.
• I used the S2 Harmonic Balancer, as it has a 2-rib design which matches the power steering pump pulley from the S2
• I swapped the entire intake. 
  • On the head there are 2 studs for the intake manifold, 1 on either end, to mount the intake along with the bolts. I used the S2 studs as they match the manifold. The ones in the NEO weren't long enough.
  • I was informed that the NEO head has smaller ports. When I did a direct comparison, the difference was basically negligible, and the intake gasket part number is the same between S2 and NEO, so it can't be that different. Nonetheless I did some very slight porting with a die grinder and I haven't noticed an issue.
• I swapped the exhaust manifold, turbo, etc and it was a direct swap.
• I added NEO Splitfire Coilpacks - these mount differently than S2 so I couldn't reuse my originals ones, in the NEO they mount directly to the head and not via brackets as seen in the S2.
• I used my S2 flywheel but they are the same as NEO
• I swapped to my S2 valve and valley covers, they were a direct swap. This wasn't a must-have.
• I used the timing belt cover and back plate from the S2 motor
  • On the NEO, the timing belt back plate has a hose that you don't need. Although not a must-do, I swapped to my S2 back plate and cover.
• I used the S2 thermostat housing
  • The NEO housing is a smaller diameter and overall different dimensions. You could use it find but would need to find the right hose. I simply swapped to S2 and it was bolt on.
• All cooling and vacuum hoses swapped over without modification
• Added S2 engine mount brackets
  • These are the same as NEO but new motor didn't come with them.

 

I think this is everything really. There honestly wasn't much to it, when I got everything plumbed it fired up without issue and without touching tune. The biggest change for me was a VCT plug which was nothing, then it was just little bits to make sure it all goes together nicely. As for the end result, you can see a comparison below along with some pics. I did all of this in my driveway basically solo  

 

 
Old motor, RB25DET S2, 238xxx kms. ARP Studs, Cometic HG, Kelford Springs, Hypergear G3 21U, E85 - 300.4 rwkw
 

 
New motor, RB25DET NEO, 250xxx kms, ARP studs, Hypergear G3 21U, E85 - 310.8 rwkw
 

 
It wasn't fun in a cold a dusty driveway covered by bunnings gazebos
 

 
New motor coming together. New water pump, pulleys and belt
 

 
Motor in the car

 

I hope this provides some useful info and helps some of you.

Cheers.

Jos

On 03/07/2021 at 1:03 PM, inmaniac said:

Hey all.

Been a very long time since I posted here but I wanted to share some info in case it is useful. I've learnt so much on SAU so I need to pay it back!

I recently blew the motor in my R33 - not sure what happened, maybe just age and stress, but it exploded the piston and rod in cylinder 5 very good. In the process it also bent a valve and caused some other damage. In my situation, I decided I would just hunt down a long motor and swap it in. I managed to find a NEO motor for a good price and decided to have a crack. It turned out to be pretty straightforward and runs great.

 
The old motor. I didn't place the rod like this, when I took off the sump it greeted me

 
NEO waiting to go in
 

There's been a bit of discussion that I've found in a few threads in this forum about what you need to do to get a NEO motor into an R33, and specifically if you were going to use the R33 (in my case a series 2) intake and exhaust manifolds. I'm going to list here what I did to get this to work. Hint: it wasn't much.
 

HERE IS WHAT I DID TO GET A NEO MOTOR IN MY R33 USING THE INTAKE AND EXHAUST FROM A SERIES 2 MOTOR:

• You must swap the VCT Solenoid plug to the "New Nissan" style. I got mine from EFI Solutions here.
   
  Old plug won't fit the NEO solenoid
  
   
  New plug was straightforward to wire. Pro tip: make sure you get the right crimp tool (you need one that does non insulated crimps)
   
• You need to swap the CAS wiring if you have the old style metal-cased CAS. (I was lucky, as I have a 40th anniversary R33, my CAS is the same as the NEO CAS, so no change needed). My understanding is the wiring is reversed, but check yourself.
• I used all accessories from the S2 motor. All brackets fit without modification.
• I used the S2 Harmonic Balancer, as it has a 2-rib design which matches the power steering pump pulley from the S2
• I swapped the entire intake. 
  • On the head there are 2 studs for the intake manifold, 1 on either end, to mount the intake along with the bolts. I used the S2 studs as they match the manifold. The ones in the NEO weren't long enough.
  • I was informed that the NEO head has smaller ports. When I did a direct comparison, the difference was basically negligible, and the intake gasket part number is the same between S2 and NEO, so it can't be that different. Nonetheless I did some very slight porting with a die grinder and I haven't noticed an issue.
• I swapped the exhaust manifold, turbo, etc and it was a direct swap.
• I added NEO Splitfire Coilpacks - these mount differently than S2 so I couldn't reuse my originals ones, in the NEO they mount directly to the head and not via brackets as seen in the S2.
• I used my S2 flywheel but they are the same as NEO
• I swapped to my S2 valve and valley covers, they were a direct swap. This wasn't a must-have.
• I used the timing belt cover and back plate from the S2 motor
  • On the NEO, the timing belt back plate has a hose that you don't need. Although not a must-do, I swapped to my S2 back plate and cover.
• I used the S2 thermostat housing
  • The NEO housing is a smaller diameter and overall different dimensions. You could use it find but would need to find the right hose. I simply swapped to S2 and it was bolt on.
• All cooling and vacuum hoses swapped over without modification
• Added S2 engine mount brackets
  • These are the same as NEO but new motor didn't come with them.

 

I think this is everything really. There honestly wasn't much to it, when I got everything plumbed it fired up without issue and without touching tune. The biggest change for me was a VCT plug which was nothing, then it was just little bits to make sure it all goes together nicely. As for the end result, you can see a comparison below along with some pics. I did all of this in my driveway basically solo  

 

 
Old motor, RB25DET S2, 238xxx kms. ARP Studs, Cometic HG, Kelford Springs, Hypergear G3 21U, E85 - 300.4 rwkw
 

 
New motor, RB25DET NEO, 250xxx kms, ARP studs, Hypergear G3 21U, E85 - 310.8 rwkw
 

 
It wasn't fun in a cold a dusty driveway covered by bunnings gazebos
 

 
New motor coming together. New water pump, pulleys and belt
 

 
Motor in the car

 

I hope this provides some useful info and helps some of you.

Cheers.

Josh.

 

 

I'm just wondering how you went on with a ECU I just blown my motor cylinder 1 brought a forged neo just starting to take the engine out and wanting to use a link ECU but which do I order do I order a neo and do they even slot into my original or would I need a adapter for the plug I have a series 1 loom am I better buying a series 2 loom