HeilSatanWorshipDoom

im sure it has been asked its 2am ive been helping people for the last 2 days so im shot so dont hound on me for not finding anything.

will aftermarket rb26 internals work in a rb25 like cams valves pistons. (im a virgin to the rb series motor) its a non neo rb25

just figure i ask before i start ordering parts.

smoked240

Rb26 factory pistons, rods and crank fit in the rb25. If you use rb26 crank you must use rb26 pistons. Rb25 crank rb25 pistons. Rods are interchangeable and it's been said the gtr rods are beefier. Cams I don't believe are. Depends on head really. It's non neo so either series 1 or 2. It really depends on how it's being built. Rb25det engine assembly is what you're working with correct?

Rawbrokerage.com has just about everything you will need. Search for which engine you're working with. I'm currently swapping rb26 stock internals into my series 2 rb25. Which will make it a 2.6L because of the wrist pin height is different between the rb25 and rb26 pistons. Hence why you must match pistons to crank. If you swap one you will have to get the block decked or piston decked. You could even have the rod shortened it's all been done. You're looking for aftermarket pistons, well I would bore enough to increase it to a 2.7 or 2.8 stroker depending on power goals and personal preference.

Info's all out there it's just picking out what's right and what's trolls haha. Have any more questions I'm sure others will chime in. Search on here: RB FAQ. There is a lot of info in that thread and if you have the time you'll fine anything you need to know. Good luck.

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HeilSatanWorshipDoom

thanks yea power isnt my focus, im focusing on response and balance. only building it to 400 whp max. thanks a lot again i appreciate it

smoked240

If you're planning on 400whp a stock rb25det engine has handled that all day(with new turbo and supporting mods of course)but I would build it a little for reliability, which is what I'm doing. The rb25det has a couple weak points you should address before making 400whp in my opinion. First is the short oil drive snout, a gtr rb26 crank already has the long snout. You can also have a collar fitted to the rb25 crank. Search under Extended crank collar. The ringlands are also an issue after 350ish. Aftermarket pistons will fix this.

I would suggest just swapping in the complete rb26 rotating assembly. That's exactly what I'm doing and going to push 500whp. Might as well get arp head studs, mains and rod bolts while you're in there. Around 500hp the head supposedly starts to lift and that will blow your head gasket.

Glad to help anytime man.

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HeilSatanWorshipDoom

yea i had a friend tell me to grab a 1jz because of the oil snout, but yea like i said reponse balance and reliability. rather do it right the first time then blow stuff up im far from rich. i got my 95 s14 for $650 usd (had to sell one of my rifles) clean just no motor so working on getting that first

smoked240

1jz is an awesome engine but I wouldn't put it in a nissan, just personal preference. I wouldn't choose jz over rb just for the oil snout issue. It's really easy to fix by removing the crank and having a machine shop fit the collar. Your best bet will be pretty much what I'm doing. Bullet proof at 500whp all day. Could probably even push 800 if you feel ballsy enough. Since you're not as long as you use good oil and change regularly you'll be set.

We're one in the same in builds haha. I've been working on my rb for almost 5 years now and finally am getting it complete.

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supersayianjim

ive also been working on my car for 5 years and iam finally getting to paint, and spare built block. and op you can just buy a awd neo. it's as close to a rb26 ad you are going to get.

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fliprayzin240sx

If you're not a purist, go 1JZ. I'd like not to worry about big turbo clearance with the damn brake mastercylinder in the way.

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silviaNC

That be silly to change swap type because a BMC imo.

Sent from my SCH-I535 using Tapatalk

smoked240

You could do a BMC delete which I might do just for simplicity. Also if you've noticed on some manifolds the turbo flange is offset forward for those chasing 900hp+

There's better reasons to go jz. I plan to own one I just hope it's in a supra instead of a ae86. I had a sick 86 in my possession in HS but I sold that foolishly.

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Sforteen

unless your shooting for over 1k whp turbo sizes up till that point are all easily fitted to the BMC side... Even over that its not a huge obstacle.

Sforteen

Shortened rods... LOL seriously

smoked240

LOL yeah bro shortened rods. You act like someone with machining back ground and a CNC mill, fuck even an upright manual mill will get the job done, wouldn't be able to shave a few MM off to make clearance. It's not easy don't get me wrong, I would do it if I absolutely had to if I needed to clear 2-3mm(depending on rod, you might be able to do more).

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fliprayzin240sx

Eh, just dont wanna risk cooking/melting the damn reservoir. Just figured they both have the same HP potential, pretty much cost the same to swap, and you'd need the same stuff to swap in (mount kit, wiring harness, custom driveshaft), so why not get the 1JZ for clearance reason.

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smoked240

It's really personal preference and what works best for the swap. If you had a rhd you would swap in the rb then?

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Sforteen

Im not saying it cant be done, i have never seen it performed, but i think id rather just have custom pistons made..

The only way to shorten a rod is machining the big end.. taking material off a rod is risky and unnecessary.

smoked240

If you know how to machine it's rather simple. If you have $800-1200 to spend on pistons then by all means. Some don't have that fortune. If I had a mill I could do it for free, why spend so much money for such little clearance.

Flip side though if it's too much and going to effect performance I wouldn't do it. Some rods have more material then others so it's really a "calls for only" mod to be real.

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