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Hi guys,

I realise that this is right up there with "how long is a piece of string" or 'how long will my rb last", but I thought I'd post the question as I've always been curious, and i seem to get so many different options and opinions when searching, that i'm not sure what is most appropriate.

I've got an internally stock RB25DET in my S1 R33 GTS-T. Just the usual bolt ons, PowerFC, front mount, 480cc, z32, splitfires, and a KKR560 that i'm replacing with a GTX3071.

My car has 160,000km on the clock, but like all imports, i have no idea if that is genuine or not, or how hard the previous owners drove it/maintained it.

Anyway, I've always wondered: how much would a rebuild cost if something went wrong with my engine?

Obviously i could get a very basic/stock rebuild, or i could go totally crazy, and each rebuilder would charge differently, so i realise these won't be perfectly accurate quotes, but what would you guys recommend for the following. It's a street car that maybe will see the occasional drift/drag/track day but i've been saying that for 2 years and haven't gotten around to a single event yet :P

[] "Stockish" rebuild to handle 275rwkw

[] Slightly tougher build for 300-325kw

I know that the "safe limit" for stock internals is around 275kw, so i'm guessing a basic rebuild, being a brand new engine rather than a 17 year old, would be able to handle at least that. Going for "value for money" and only spending where it needs to be spent, what more would I get to handle 300 to 325 kw. I know I can go insane and get new intake and exhaust manifolds, cams, and everything else, if money is no object, but what's recommended for these power levels? I'd more want "responsive street car" rather than "peaky screamer" as i'm over the lag from my current turbo, I'd pretty much just be looking for whatever the maximum a GTX3071 could safely deliver on 98 fuel, which should be similar to a GT3076.

Am I an idiot if I get a rebuild and don't get cams? Exhaust manifold? Intake manifold? RB30 bottom end :wub:?

I guess I'm just looking for peoples experiences and how happy they were with the money spent.

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Yogi, RB30DET gives me boners!

When I first read about them, a few years ago, I thought it was just a "bolt RB25 head onto RB30 bottom end and your done" type thing, which sounded awesome, so I looked more into it and realised that there was much more to it than that, so I kinda forgot about it. Guess I'll hit that search button now and see what i can find :)

it depends i used to be an engine rebuilder. i built a rb30 with Hbeam conrods crow cam forged pistons acl race series bearing port and polish etc. for 350kw i would get forged pistons acl race series bearings and race series gasket set. prob no need for the rods but while you have it apart why not because eventually your going to want more power once you get the bug. with the cams read my recent post on whether its worth changing cams or not. should give you a good idea but the mains things i would do would be forged pistons acl race series bearings and gasket set and if you hae a little extra cash maybe get a port and polish.

Why is the limit of stock internals 275rwkw?

Had them safely running at 375rwkw for ages.

There is no difference between an engine build for 250rwkw and 350rwkw. Basically you can choose forged rods etc but if you put them in regardless all up you'd be looking at around $10k for that type of build with all the parts supplied

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I stroked my RB25 to 26 retaining the 25 head.

Head Decked with new valve springs and replacement $1450 Cash

Nissan OEM RB26 Crank $1450

Machine Block & ARP Studs $1700

Forged Piston and Spool Rod Rebuild Kit RB26 ( including Bearings and Head Gasket ) spoolimports.com $2250

Nissan OEM Engine Gasket Kit $375

Labour at mates rates about $700 to $1000

$8225

If you machine your crank about $500 so I went new

http://www.proengines.com.au

Nissan RB25/RB26 short engines.

This is a completely remachined and assembled short engine.

Engine is stripped and chemically cleaned

Block rebored and torque plate honed

Head gasket surface CBN milled to suit MLS gaskets

Crankshaft balanced, micropolished and fitted with screw in oil gallery plugs

Oil pump drive collar supplied and fitted

Connecting rods resized, fitted with new bolts and pin bushes and balanced

Short engine assembled using new forged pistons and rings, ACL race series bearings, new N1 oil pump, seals, painted and fitted with oil & water plugs.

Price: $5200 including GST

Options:

Price AU$

Spool H-beam connecting Rods- ARP2000 bolts

add $900.00

ARP Main Stud kit- RB20/25/26/30 10mm

add $275.00

ARP Head Stud kit- RB26DETT 12mm

add $493.00

ARP Main Stud kit- RB20/25DET 11mm

add $250.00

i paid around 5-7k for my rebuild

10k will get swallowed up pretty easily.

Its all the small things you dont think about until you need it that makes it expensive.

Yup, things like a new balancer, pullies, fittings a good sump etc all add up, the basic short motor is cheap, but the extras that should go into a build are the expensive bits.

Take my old Rb25 - it had some good gear inside, but all the outside bits kept letting it down that I really shouldve replaced at the same time but my budget didn't allow for.

  • 2 months later...

Hey guys,

I've got all the usual bolt on's and a power FC. Had a KKR560 on there, but Gavin Wood couldn't get more than 250kw out of the car (these turbos are laggy but can do over 300kw)

Just last week I had a GT3076 put on with a 0.82 housing. 50mm external gate on factory manifold. screamer pipe. adjustable cam gear.

Car got tuned again by Gavin, got exactly the same power output of 250kw at 1.1bar

Gav said that the engine isn't making more power with more timing or boost, and that it's probably because it's an old engine (1993) or a carbon buildup. Either way, only way to get more power is an engine rebuild. I know he's playing it safe, because i'm a customer and he doesn't want to blow up my car, but i'm just wondering, if i want to make the most of my 3076, what sort of rebuild do i need? Could I just do a stock RB30 bottom end, clean everything up while it's out, and put on my current head... or would i be forever kicking myself that i didn't spend thousands on all the good parts while the engine is out?

I'm just looking for 300kw for 99% street driving.

No need to rebuilt for that power figure. I've been making 281kw for over a year now and engine is still awesome. No signs of dying.

Neither did Hamish's @ 300rwkw or whatever figure around that. Was fine one day, wasn't the next.

Issue is I think people need to prepare to rebuild at some point.

Motors are what, 15+ years old now. They ain't gonna last forever no matter how good the tune is :)

If you really want to do it on a budget why not just freshen up a bog std RB30 short motor ? I think if you tune an engine properly and its a street car getting more torque is not an issue . A 20% bigger engine doesn't need to run in a real high state of tune to be good enough .

IMO the only significant disadvantage with an RB30E short is the lowish compression ratio with a twin cam head on it . The heads can be decked a little and you may get it up to 8.4-8.5 which is livable on the street .

Anyway on a tight budget its what I'd do , the only extra I'd contemplate is ceramic coating the piston crowns because 30's don't run oil squirters and they are difficult to impossible to fit .

I think the urban myth is that you need 300 RWKW to spin the wheels and it just isn't so , trust me you can do it with a 200 crank Kw RB25det in std turbo trim and as we know power beyond wheelspin is useless .

The extra 500cc's and better rod/stroke ratio makes it better streeter because the extra off boost torque you can use all the time .

Where these cars let you down is that your not going to pull a punchy AWD turbo terror off the line because you can't get all your power to the ground . They are limited two those two rear contact patches and the weight on them .

Anyway IMO a budget 30 will feel better than a more highly strung expensive 25 , it just depends on where "adequate" is for you and how hard you work your street engines .

A .

  • Like 1

The heads can be decked a little and you may get it up to 8.4-8.5 which is livable on the street .

Last time we measured mine + cubes was around 9:1

Lets be serious here. You want to drive it on the street and have good power. The std motor will do that on a reliable tune. It depends on how much work you want to do yourself as to pricing. Are you referring to drop the car off and pick it up, pulling the motor and fitting yourself, or getting the short motor built and fitting the head, or having the parts machined and assembling yourself?

See how complicated it gets?

A motor recondition would be about 3k back to std if you drop the motor off. Get it balanced and thats extra.

Forged pistons add over 1k to that easy, but why do you need them for a street driven car with a good tune?

Think about what you want to do, and stick to it or it will end up blowing 10k easy.

btw, 3k stock rebuild doesnt add fluids, pre and post tune etc so it will blow out easy.

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