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RB25 Crankshaft Differences

LjB123

By LjB123,
in R Series (R30, R31, R32, R33, R34)

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LjB123 Enthusiast

LjB123

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Posted

Hello. Was wondering if the RB25 crank shafts were same/similar across the range? What are the differences? 
 

I couldn’t find a definitive answer, and have a Neo series motor and needed a new crank. I can find plenty for sale but obviously want to make sure there isnt any difference between one from say an R33, and my current one

 

Also out of curiosity, is there a difference between the RB25DET blocks themselves from an R34 and R33?

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GTSBoy Grand Master

GTSBoy

Posted
Posted

They're all essentially the same**. Although you have to differentiate between "block" and "bottom end", because Neos have different pistons and rods to vanilla 25s.

I won't speak to whether there were oil pump drive changes to take into consideration, as that can be fixed anyway.

LjB123 Enthusiast

LjB123

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Posted
6 hours ago, GTSBoy said:

They're all essentially the same**. Although you have to differentiate between "block" and "bottom end", because Neos have different pistons and rods to vanilla 25s.

I won't speak to whether there were oil pump drive changes to take into consideration, as that can be fixed anyway.

Thanks heaps. So basically, bare block, very very similar. And cranks are the same

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted
12 hours ago, GTSBoy said:

won't speak to whether there were oil pump drive changes to take into consideration

Both NEOs I bought had short oil pump drives on them, even though internet legend has it they introduced longer collars on them.

However, it's true NEO motors used N1 sized oil pump gears and not the same ones found in the R33 RB25 motor.

Block wise, NEO has the front head VCT drained blocked off, but you can easily remove that.

LjB123 Enthusiast

LjB123

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22 minutes ago, Dose Pipe Sutututu said:

Both NEOs I bought had short oil pump drives on them, even though internet legend has it they introduced longer collars on them.

However, it's true NEO motors used N1 sized oil pump gears and not the same ones found in the R33 RB25 motor.

Block wise, NEO has the front head VCT drained blocked off, but you can easily remove that.

Thanks. So crank is the same, stroke and everything is the same? Im getting crank collar installed anyway

 

I have heard this internet myth as well, but ive had a few unopened Neos as well and no long nose crank. Supposedly it may have been a series 2 thing? The ones I had were from series 1’s. No idea haha

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted
19 minutes ago, LjB123 said:

Thanks. So crank is the same, stroke and everything is the same? Im getting crank collar installed anyway

Correct :)

And whatever you do, don't use an oil pump gear, especially the one that starts with the same letter as Santa and the last letter ends with the same first letter as Lagoon. Get a proper oil pump, like a Nitto, Tomei, etc. and make sure you invest in a big fk off sump.

Won't go into too much detail, but I am sure it caused my previous built motor to go bang.

TurboTapin Proficient

TurboTapin

Posted
Posted
39 minutes ago, Dose Pipe Sutututu said:

Correct :)

And whatever you do, don't use an oil pump gear, especially the one that starts with the same letter as Santa and the last letter ends with the same first letter as Lagoon. Get a proper oil pump, like a Nitto, Tomei, etc. and make sure you invest in a big fk off sump.

Won't go into too much detail, but I am sure it caused my previous built motor to go bang.

No issues here with my PRP gears in an OEM pump housing. I did confirm all housing clearances were to spec prior though. Cheers. 

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LjB123 Enthusiast

LjB123

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On 11/12/2024 at 11:42 AM, Dose Pipe Sutututu said:

Correct :)

And whatever you do, don't use an oil pump gear, especially the one that starts with the same letter as Santa and the last letter ends with the same first letter as Lagoon. Get a proper oil pump, like a Nitto, Tomei, etc. and make sure you invest in a big fk off sump.

Won't go into too much detail, but I am sure it caused my previous built motor to go bang.

Well my freshly rebuilt RB25DET Neo went bang 1000kms in, completely fried big end bearing in cylinder 1 so bad my engine seized. No knocking or oil pressure issue prior to this happening, all happened within less than a second. Had Nitto oil pump, 8L baffled sump, head drain, oil restrictors, the lot put in to prevent me spinning a bearing like i did to need the rebuild. Mechanic that looked after the works has no idea what caused it. Reckoned it may have been bearing clearance wrong in cylinder 1 we have no idea. Machinist who did the work reckoned it was something on the mechanic. Anyway thats between them, i had no part in it, just paid the money

Curiosity question, does the oil system on RB’s go

sump > oil pump > filter > around engine?

If so, if you had a leak on an oil filter relocation plate, say

sump > oil pump > filter > LEAK > around engine

would this cause a low oil pressure reading if the sensors was before the filter?

 

TIA

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