Jump to content
SAU Community

Recommended Posts

Hey guys

I have a standard RB25 that is laughing at my 300rwkw. (Loves the water meth though). It has some small problems, like the sump gasket leaking, and the synchros need a service etc. Engine and gearbox have to come out to fix these problems, so while they are out, lets just put a RB30 back in there? lol.

So what I want to do, is install a standard built RB30 and sell off my Complete RB25.

What I have:

RB25 complete head, lightly ported.

RB30 NA Block complete Still built, only head off, only 160,000kms, hone marks still in bore.

GTR Oil Pump

Ok so here is my plan:

1. RB30 block dissasembled, acid bathed, xrayed, honed and decked slightly. Maybe a little more to raise the compression a tiny bit.

2. Drill and tap hole for New tensioner.

3. Head cleaned and reconned.

4. Grub Screw VCT oil feed in head, and do the internal VCT oil feed mod, block rear oil feed, 1mm restrictor in front feed.

5. GTR oil pump cleaned and checked.

6. Get crank checked. Fit crank collar.

7. Assemble RB30 Block with original pistons, rods, and crank. New Rings, main and big end bearings.

8. Bolt head on with Head gasket (not sure what I use yet)

9. New Water pump, timing belt, RB25 Harmonic balancer.

10. Screw cleaned up, milled, and sealed china copy side mount intake manifold onto head.

11. Install Injectors, Water meth, throttle body.

12. Install Exhaust manifold.

13. Install Turbo (GT3037) with a 0.82 rear housing.

14. Have exhaust modified, and intake piping fixed. Install big ass f**k off stupid twirly, duck whistle, fluttering blow off valve so women take their clothes off and jump into the car. Install Factory BOV, and plumb back.

15. Drop engine back into car.

16. Install Gearbox.

17. Run in on dyno, maybe just on the street.

18. Drive around.

19. Run 11's down the quarter.

20. Post a thread on SAU about it.

Questions:

1. What rings should I buy for the standard pistons? - Can anyone recommend any?

2. What bearings, and what clearances should I run?

3. Have I missed anything stupidly important or worth mentioning?

Car has Nismo 555's, GT3037, WMI, 600x300x75 IC, 3.5inch exhaust, Powerfc, I tune it, etc.

Currently making an easy 310rwkw+ on 20psi. Been like that for 2 years now, and compression tests are all still consistant and high. Wish I new if it had forgies or not, its a bit of a weird one to be honest with you. I'll have a look when I have the sump off.

Edited by The Mafia
  • Replies 46
  • Created
  • Last Reply

Top Posters In This Topic

I was thinking about it, but do you think that is really necessary for 300rwkw and a povo build? Only be reving it to 7,000rpm, maybe a tiny bit higher if others think its safe to, and if the turbo has enough puff.

Edited by The Mafia

sounds loke a simple but effective engine.

If I was going to build one again, and i probably will shortly, I would use gtr rods prepped and a set of forgies and new rod bolts. but that would be to lean on it harder and shoot for 400rwkw. totally un nessacary power figure but I have all the supporting mods for it.

for your power figure it sounds like a good reliable combo.

my build had less effort put into it and pushes 320rwkw now and shows no signs of trouble. rev limiter set to 6700 now

sounds loke a simple but effective engine.

If I was going to build one again, and i probably will shortly, I would use gtr rods prepped and a set of forgies and new rod bolts. but that would be to lean on it harder and shoot for 400rwkw. totally un nessacary power figure but I have all the supporting mods for it.

for your power figure it sounds like a good reliable combo.

my build had less effort put into it and pushes 320rwkw now and shows no signs of trouble. rev limiter set to 6700 now

you cant use the GTR rods they are too short for a 30.

I was thinking about it, but do you think that is really necessary for 300rwkw and a povo build? Only be reving it to 7,000rpm, maybe a tiny bit higher if others think its safe to, and if the turbo has enough puff.

its not necessary to balance the engine but i got mine balanced when i got it built (for the price i figured i might as well) to +/- 0.05g and the engine feels like it just wants to rev, though it only has a 7400rpm limiter on it at the moment.

hey mate just out of curiousity, are you gonna assemble the bottom end yourself?

Kind of, my mate is a diesel fitter and he's coming over to do it, and I will be assisting.

He's done a couple before, knows what he is doing.

I've since found some bargains:

1. Got a set of ACL duralite Pistons (Stock replacements, but heaps lighter) these are balanced.

2. RB30 rods, Balanced.

The ACL pistons came with rings, should I use these or get better ones? I will have to get the details on them for you all.

1. Got a set of ACL duralite Pistons (Stock replacements, but heaps lighter) these are balanced.

2. RB30 rods, Balanced.

The ACL pistons came with rings, should I use these or get better ones? I will have to get the details on them for you all.

I have heard the ACL pistons are not as good as the stock ones from Nissan maybe be something to check out.

Kind of, my mate is a diesel fitter and he's coming over to do it, and I will be assisting.

He's done a couple before, knows what he is doing.

I've since found some bargains:

1. Got a set of ACL duralite Pistons (Stock replacements, but heaps lighter) these are balanced.

2. RB30 rods, Balanced.

The ACL pistons came with rings, should I use these or get better ones? I will have to get the details on them for you all.

balancing should be done as a package not individually.

As MBS206 said i would not touch the bottm end, just bolt the head on. Unless your going to bore it and use nissan rings or better, i dont think you will get as good seal as the stock motor/rings.

I had a stocker bottom endwith over 300,000kms on the vl it came from in a r32 it made 312rwkw for couple of years before i decided to build a 4wd forged motor. Trick is to keep revs to 7000rpm or under.

As MBS206 said i would not touch the bottm end, just bolt the head on. Unless your going to bore it and use nissan rings or better, i dont think you will get as good seal as the stock motor/rings.

I had a stocker bottom endwith over 300,000kms on the vl it came from in a r32 it made 312rwkw for couple of years before i decided to build a 4wd forged motor. Trick is to keep revs to 7000rpm or under.

did you freshen the bottom up, with new bearings and rings, or just slap a head on it?

if you wanna be really right and not buy proper restrictors then you can seal up the standard one (seen a pop rivet used) and drill a smaller one next to it

you should use ACL race series bearings. a set of arp rod bolts and chuck it together with the stock nissan pistons with new standard rings. they are much better then the acl pistons you have mentioned.

balance it as well, rb30's dont like to rev at the best of times so a quick cheap balance will do some good.

as long as you keep detonation away from the engine then it will be fine for over 300rwkw

straight motors are easy to balance as they are rarely out of balance and if they are its never much. but if they are out of balance, 0.01 grams at 750 rpm can become 0.5grams at 5000rpm or more i forgot the exact maths, but end result bigger vibrations creating unneeded wear and tear

though your list does have pretty much everything thats needed

for a cheap cheap job you could just drill the hole for the tensioner new timing belt, gaskets etc, and whack it all together

though better to use the rb25 pistons and king bearings

if your in sydney send it to my machine shop

Edited by Gerg_R31
though better to use the rb25 pistons and king bearings

Doesnt that lower the compression to some stupidly low CR?

Also, i read in another thread that balancing the crank is bad because of something to do with it being nitrided?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Sounds like you've got an interesting adventure ahead here with local support if you have trouble! My guess is that, unboosted, you will be OK with a small upgrade like -9. What will happen is that once the stock ECU sees more airflow than it expects it will add a heap of fuel and pull a heap of timing to be safe because it can't understand how it could get that much air without there being an issue. You will see clouds of black smoke and it won't pull hard through the midrange and top end. So, overall it will be a bit frustrating but should be OK. If you are still nervous set the base timing back 2o through the CAS, but it will be even more sluggish everywhere. As said above through...this is not my guarantee your engine won't be blown into a million pieces, leaving you looking for very hard to find parts A better idea is get a computer with logging ASAP, wire in a wide band O2 sensor and a use remote tuner. I've done multiple cars this way and while it is not as good as a specific tune on a dyno they can get it 90% right. I'd suggest if you can afford an R33 GTR these days you can afford an ECU and tune. And if you can't afford that you sure won't be able to afford the rebuild if it goes bad in the meantime,.  
    • Yeah it would be nice if someone took the time to put that sort of information together, but there are a lot of variations in looms. I think you are making this way hard for yourself if you just want to get it running....sourcing an SR20 with the right wiring will be a billion times easier than matching the RB loom to an S15 chassis. If you do end up going this way, you just need to trace every wire in the loom with a multimeter, 95% of them will go to a location you can confirm at the ECU.....and then post it up for the next person who needs it  
    • Just top it up with water, and keep a general idea of how much you added. It is normal for water to be pushed into and pulled out of the reservoir through the cap, and it should not be more than half full or it will be likely to overflow when hot. Any decent mechanic can do a pressure test of the cooling system to confirm if you have a leak. Keep in mind if it is only leaking a little and when hot it may well evaporate before you see it hit the ground
    • I'd ask the shop what they used and use that. Mixing coolants is sometimes OK, sometimes not, and you have know the details of each coolant to know whether it's a good idea or not.
    • Is it alright to top up with just another green coolant?
×
×
  • Create New...