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Rb26 Crank In A Rb25

dori34

By dori34,
in Engines & Forced Induction

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  • 2 months later...
Turbo_Knuff Enthusiast

Turbo_Knuff

Posted
Posted (edited)

Hello

I wonder what bearings do I need to use if I put an rb26 crank in a rb25 block? Should I use rb25 or rb26 bearings?

Im also wonder if anyone know what the C/R would be with the rb25det head and rb26 internals in the bottom? I want a C/R like 9:1 what should I do to get that?

Edited by Turbo_Knuff
  • 3 months later...
fomby639 Enthusiast

fomby639

Posted
Posted (edited)

^^^ i would also like to add, can you use rb25 crank with new rb26 rods and forged rb25 pistons? what hp/rpm is standard rb26 rods good for? is it cheap to go this path than a set of aftermarket rb25 rods?

cheers

Edited by fomby639
zebra Grand Master

zebra

Posted
Posted

By the time you prep a set of 26 rods (resize, linish etc) you are nearly at a set of Eagles or Spool H-beams.

most people rate the factory 26 rods at ~400rwkws, there are the same length as 25 rods, just beefier.

DR 32R Rising Star

DR 32R

Posted
Posted
^^^ i would also like to add, can you use rb25 crank with new rb26 rods and forged rb25 pistons? what hp/rpm is standard rb26 rods good for? is it cheap to go this path than a set of aftermarket rb25 rods?

cheers

A lot of internet specials around atm such as rb26 cp pistons and forged rods 1k us dollars. You need the rb26 pistons with an rb26 crank.

Aberax Grand Master

Aberax

Posted
Posted
Hello

I wonder what bearings do I need to use if I put an rb26 crank in a rb25 block? Should I use rb25 or rb26 bearings?

Im also wonder if anyone know what the C/R would be with the rb25det head and rb26 internals in the bottom? I want a C/R like 9:1 what should I do to get that?

Would also like to know which Main Bearings to use. The ACL part numbers for the Rod Bearings are the same (6B2960H, 6B2960HX) for RB25 and RB26 Rods. However the Main Bearings for RB25 are 7M2395H/HX - Flange, and 7M2394H/HX, the RB26 part numbers are 7M2428H/HX - Flange, and 7M2429h/HX.

The difference on ACL's website says the RB26 Bearings are slightly longer

RB25 RB26

7M2395H/HX - 1.061in / 26.95mm 7M2428H/HX - 1.063in / 27mm

7M2394H/HX - 0.7528in / 19.12mm 7M2429H/HX - 0.7874in / 20mm

My guess would be to use the RB25 Bearings as it is going into a RB25 block, as long as the crank is the correct diameter where you bolt the crank down, I suppose :ermm: .

  • 7 months later...
boz_soljah Mentor

boz_soljah

Posted
Posted

Alot of good info here

here is what i have and what im planning to do

ive got a bare 25 block

ive got R32 gtr crank

26 h-beam rods

still lookin out for pistons, i want to oversize them

i still dont no what bearing to usee....

do i have to modift the oil pump or upgrade it, or will the 25 one be good

im aiming for 400+kw maybee 500,,

ive got 2x t67 turbos, i dont no if i should twin turbo it or just get a Big single,,, dont want it too laggy

ive also heard people have done 2.8 with the gtr internals,, anyone no about this???

Aberax Grand Master

Aberax

Posted
Posted

still lookin out for pistons, i want to oversize them

Take your pick, there are plenty of brands out there. You will either want 86.5 or 87mm pistons. I went with CP 86.5 so if I need to rebuild again I can go to 87mm.

i still dont no what bearing to usee....

RB26 Bearings as you are using a RB26 crank. Use ACL Bearings, they are Aussie made :thumbsup:

do i have to modift the oil pump or upgrade it, or will the 25 one be good

im aiming for 400+kw maybee 500,,

Upgrade it, you are spending the money on a rebuild and the oil system is the life of it...it is one thing you don't want to skimp on. If it fails/breaks, the outcome could be catastrophic.

If you are aiming for 400kw+ then definitely upgrade the oil pump.

ive got 2x t67 turbos, i dont no if i should twin turbo it or just get a Big single,,, dont want it too laggy

Twin turbo RB25...too much hassle to make the manifolds etc, do a search on SAU. I think a few people have done it on here, but its a PITA.

And in regards to the thread you started that got locked, look here, I am currently doing this build and documenting it a bit.

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