Jump to content
SAU Community

Recommended Posts

  • Replies 137
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

With a set of forged rods or getting the stock ones shot peened, how far can the RB30 rev? how far past 7000rpm??? If I spent $750 on a set of rods and bolts for an N/A application I would want to be able to rev its a@s off all day everyday :-)!!!

I don't think its necessarily so much the rods that limit the rpm, when it comes to rb30 blocks i have read that they experience harmonic issues at around 7500 RPM because the block simply wasn't designed for that RPM and doesn't have the strength to brace those vibrations.

You can do whatever you want with the rods but if you want to see high RPM i think you would have to fork out for an RB26 N1 block.

Anyway thats just my 2cents

Much more than 7k you need rods AND an ATI balancer if you want it to hold together.

Its really just like the RB26 and RB25 at 7.5k+ and lots of track work. If you want it to hold together you must throw an ATI balancer at it.

Balancer and rods and 8-8.5k is not a problem. The VLT's back when I owned one were doing it back in their day. Tried and proven if you like.

Regardless how many rev's do you want. 8-8.5k is more than enough especially from the 3ltr. A turbo to suit such airflow requirements is pushing 1000hp. N/A its a different story.

Possibly a 26 is a better bet. ATI balancer, rods and pistons big cams and aim for 10k. :nyaanyaa:

  • 2 weeks later...
  • 2 weeks later...

I have just recently had a 26/30 built up n/a and here are some answers that your chasing are as follows and some prices

Crank:

- If your running the 30 bottom end you'll have a RB30 crank no doubt, now with the RB30 crank there are little plugs in the crank from where holes get drilled through it so these HAVE to be removed if your revving the motor past 6000rpm (have a tendency to fly out, not good!) and have them replaced with grub screws and get them knocked into place with like a centre punch so they definitely won't come out.

- You'll also need a crank collar ($165) if you upgrade the oil pump (I think it is if you replace the oil pump), i'm running a GTS-T oil pump which is more than enough cause the GT-R pumps will give to much pressure for a n/a setup due to the fact that the GT-R's have piston squirters and turbo's.

Rods:

- True the RB30 rods can withstand 250+rwkw (way more power than what you'll see out of a n/a 30) but the thing is taking them past there breaking point and it may only require 50rwkw at 8000rpm and twang there goes a rod so rods are a good idea also, I don't have rods yet and it doesn't mind being taken out to 7000rpm every now again.

Block:

- I'm using 30 rods with 25DE pistons, the block was chopped 50 thou (don't know how many mm that is) and the head was taken back a bit and I think the pistons had some meat taken off them as well from memory, if you want more accurate measurements I can contact people that put the motor together, either way it runs over 12:1 and under 12.5:1 CR. Very Nice!

All the machine work cost a bit under $2G and there is still more to go.

If your not keen on spending a lot of money straight up, then I wouldn't bother with cams and gears at this point in time unless you can get a sweet deal on either items, but seeing as how you have a non-turbo head everything to do with the cams will suit the n/a application.

Unlike myself everything is operating in turbo mode (f***ing annoying), will be getting gears first to dial the cams in a bit better then i'll throw some sticks at it. Hopefully it'll see the 230rwhp mark. :rofl:

  • 3 months later...

Im building my na rb30de for my r34 soon. I plan to run it as stock as possible with an safc to add the extra fuel. Just wondering if anyone can answer some questions.

1.Will the rb25de pistons fit or must i bore it out?

2.what compression will i have by changing to the 25de pistons?

3.to use my original rb25de oil pump will i need a collar?

4.I plan on tappin into the oil pressure sender and plumbing the vct (how is this done?)

5.Do i need to change to a different oil restrictor?

6.What must i do to the head face to bolt it onto the rb30?

7.Is there any extra oil plum bing for the rb25de head?

Thanks

1.) The 25DE pistons will fit without boring (I'm using 25DE pistons)

2.) Don't know what compression you'll have but it'll be far too low for what you need, so you'll have to get the block machined.

3. ) I think you do need to run a crank collar

4.) don't know??

5.) I'm using oil restrictors but you they're not completely necessary but nice to have

6.) do you mean machine the head? or the tensioners?

7.) don't know?

I don't know about that either, but there has been some people on here that have done the twin cam conversion with that head so you should have a look around and ask some that have done it to see what they did or get a 26 head :D

Is anyone doing the RB25/30 N/A Conversion with RB25DE N/A pistons, remembering hearing about this fellow with a 240z who used,

RB30E block, crank and rods, RB25DE N/A pistons and decked the block to get about 10.5:1 compression ratio - using the pistons to get a higher compression ratio as opposed to shaving 2mm of the head would be a better idea wouldnt it?

Has anyone gone down the RB25DE N/A piston route when building there RB25/30 N/A motor?

Lower piston crowns also produce less torque as the piston crown is closer to the crank so you lose leverage on the crank. Nm = force x distance. .

If I were you id look into getting a flat top hyper-eutectic piston made with a deck height of 0. . You can get them custom made with valve notches and to suit the bore size. . its around $900 I think. . (comes with rings, pins etc)

I mean the mating surface of the head, must i modify any oil galleries or water jackets? Im only aiming for 10.5-1 comp...

All galleries and jacket line up.

You will have to machine the suface of the head to ensure its flat.

If you have a warped head it will cause problems with a good seal and could run into head gasket problems down the road.

  • 2 weeks later...

I looked into getting custom cams made at SureCams. . He quoted me 770 but I cannot remember if that was for both or just one :S ill give him call back. .

Just wondering what an ideal lift and duration would be. . I was thinking around 270 duration and 9mm lift. . ?

Im using a custom made set of pistons and aiming for 11:1 comp ratio, so keep that in mind :huh:

  • 1 month later...

Ok,

Update on my build :down:

My cams have arrived, intake 10.7mm 264deg, exhaust 10.2mm 270deg. .

Bad news is that one out of three of the oil gallery bolt holes (on the corner of the head) has snapped off. . so I have to get it all welded up and drilled. .

I have ordered pistons, custom forged dome topped pistons.. Good thing about this is that when it comes time for a turbo, I dont have to touch the bottom end for it to hold big power (400rwkw), as rods and pistons are forged and fully balanced :P

Thats about it for now. . Oh and I took a slapped it together just to see how it would look, kind of

P200309_143401.jpg

P200309_143402.jpg

P200309_143403.jpg

Any of you guys seen the specs on this bad boy??

post-12712-1237713364_thumb.jpg

Change engine RB30E

RB26DETTヘッド改 Kai head RB26DETT

カム IN EX 共に300度 ポート加工 HKSスライドカムスプロケ IN EX cam with 300 degrees port processing HKS SURAIDOKAMUSUPUROKE

RB26用6連スロットル改 RB26 for improved throttle for 6

スポーツインジェクション SUPOTSUINJEKUSHON

等長ステンタコ足 Isometric leg SUTENTAKO

FコンVプロ Pro Con V F

R33樹脂製燃料タンク R33 plastic fuel tank

オプティマバッテリー(リア) OPUTIMABATTERI (rear)

Z32ラジエータ Z32 radiator

RB30 block

RB26DETT head, prepped and ported

300 degree inlet and exhaust cams

six throttlebody intake with trumpets (sports injection)

HKS F CON V pro computer, (map sensor based)

And 380 HP at the crank.

  • 2 weeks later...
  • 7 months later...

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

    • Thanks, I removed the fuse and the relay from the car and made my own circuit with them to test them with a test bulb.  I will look for the wiring diagram and go from there.
    • Jdm DC2R is also nice for a FF car compared to the regular hatches of the time.
    • Now that the break-in period for both clutch and transmission is nearly over I'd like to give some tips before I forget about everything that happened, also for anyone searching up how to do this job in the future: You will need at least 6 ton jack stands at full extension. I would go as far as to say maybe consider 12 ton jack stands because the height of the transmission + the Harbor Freight hydraulic platform-style transmission jack was enough that it was an absolute PITA getting the transmission out from under the car and back in. The top edge of the bellhousing wants to contact the subframe and oil pan and if you're doing this on the floor forget about trying to lift this transmission off the ground and onto a transmission jack from under the car. Also do not try to use a scissor jack transmission lift. You have to rotate the damn thing in-place on the transmission jack which is hard enough with an adjustable platform and a transmission cradle that will mostly keep the transmission from rolling off the jack but on a scissor lift with a tiny non-adjustable platform? Forget it. Use penetrating oil on the driveshaft bolts. I highly recommend getting a thin 6 point combination (box end + open end) wrench for both the rear driveshaft and front driveshaft and a wrench extension. These bolts are on tight with very little space to work with and those two things together made a massive difference. Even a high torque impact wrench is just the wrong tool for the job here and didn't do what I needed it to do. If your starter bolts aren't seized in place for whatever reason you can in fact snake in a 3/8 inch ratchet + 6 point standard chrome socket up in there and "just" remove the bolts for the starter. Or at least I could. It is entirely by feel, you can barely fit it in, you can barely turn the stupid ratchet, but it is possible. Pull the front pipe/downpipe before you attempt to remove the transmission. In theory you don't have to, in practice just do it.  When pulling the transmission on the way out you don't have to undo all the bolts holding the rear driveshaft to the chassis like the center support bearing and the rear tunnel reinforcement bar but putting the transmission back in I highly recommend doing this because it will let you raise the transmission without constantly dealing with the driveshaft interfering in one way or another. I undid the bottom of the engine mount but I honestly don't know that it helped anything. If you do this make sure you put a towel on the back of the valve cover to keep the engine from smashing all the pipes on the firewall. Once the transmission has been pulled back far enough to clear the dowels you need to twist it in place clockwise if you're sitting behind the transmission. This will rotate the starter down towards the ground. The starter bump seems like it might clear if you twist the transmission the other way but it definitely won't. I have scraped the shit out of my transmission tunnel trying so learn from my mistake. You will need a center punch and an appropriate size drill bit and screw to pull the rear main seal. Then use vice grips and preferably a slide hammer attachment for those vice grips to yank the seal out. Do not let the drill or screw contact any part of the crank and clean the engine carefully after removing the seal to avoid getting metal fragments into the engine. I used a Slide Hammer and Bearing Puller Set, 5 Piece from Harbor Freight to pull the old pilot bearing. The "wet paper towel" trick sucked and just got dirty clutch water everywhere. Buy the tool or borrow it from a friend and save yourself the pain. It comes right out. Mine was very worn compared to the new one and it was starting to show cracks. Soak it in engine oil for a day in case yours has lost all of the oil to the plastic bag it comes in. You may be tempted to get the Nismo aftermarket pilot bearing but local mechanics have told me that they fail prematurely and if they do fail they do far more damage than a failed OEM pilot bushing. I mentioned this before but the Super Coppermix Twin clutch friction disks are in fact directional. The subtle coning of the fingers in both cases should be facing towards the center of the hub. So the coning on the rearmost disk closest to the pressure plate should go towards the engine, and the one closest to the flywheel should be flipped the other way. Otherwise when you torque down the pressure plate it will be warped and if you attempt to drive it like this it will make a very nasty grinding noise. Also, there is in fact an orientation to the washers for the pressure plate if you don't want to damage the anodizing. Rounded side of the washer faces the pressure plate. The flat side faces the bolt head. Pulling the transmission from the transfer case you need to be extremely careful with the shift cover plate. This part is discontinued. Try your best to avoid damaging the mating surfaces or breaking the pry points. I used a dead blow rubber hammer after removing the bolts to smack it sideways to slide it off the RTV the previous mechanic applied. I recommend using gasket dressing on the OEM paper gasket to try and keep the ATF from leaking out of that surface which seems to be a perpetual problem. Undoing the shifter rod end is an absolute PITA. Get a set of roll pin punches. Those are mandatory for this. Also I strongly, strongly recommend getting a palm nailer that will fit your roll pin punch. Also, put a clean (emphasis on clean) towel wrapped around the back end of the roll pin to keep it from shooting into the transfer case so you can spend a good hour or two with a magnet on a stick getting it out. Do not damage the shifter rod end either because those are discontinued as well. Do not use aftermarket flywheel bolts. Or if you do, make sure they are exactly the same dimensions as OEM before you go to install them. I have seen people mention that they got the wrong bolts and it meant having to do the job again. High torque impact wrench makes removal easy. I used some combination of a pry bar and flathead screwdriver to keep the flywheel from turning but consider just buying a proper flywheel lock instead. Just buy the OS Giken clutch alignment tool from RHDJapan. I hated the plastic alignment tool and you will never be confident this thing will work as intended. Don't forget to install the Nismo provided clutch fork boot. Otherwise it will make unearthly noises when you press the clutch pedal as it says on the little installation sheet in Japanese. Also, on both initial disassembly and assembly you must follow torque sequence for the pressure plate bolts. For some reason the Nismo directions tell you to put in the smaller 3 bolts last. I would not do this. Fully insert and thread those bolts to the end first, then tighten the other larger pressure plate bolts according to torque sequence. Then at the end you can also torque these 3 smaller bolts. Doing it the other way can cause these bolts to bind and the whole thing won't fit as it should. Hope this helps someone out there.
×
×
  • Create New...