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I have read this thread a few times before, but have gone over it tonight after having done lots more browsing around the place, and I'm up to about page 85.

I have a few questions, related to purchases I either need to make or not make, tomorrow.

So you get some perspective on where I am coming from I'll give you a brief rundown. I'm a first year Psych/Law uni student, working in retail, and I'm trying to put together something affordable yet relatively quick. A 'freshened' RB30E bottom-end and 'freshed' RB25DE head, running ~250KW@RW.

I'm aiming for what SydneyKid got in his original RB30DET build. If you could induldge me in a more detailed explanation of what you did all those years ago, in terms of the work you did to prepare the block and head and which parts were new/second-hand, and which were serviced or just used as-is, that would be OUTSTANDING.

Instead of the T04 turbo, maybe something more modern, such as a GT3040? Ideally I'd like it to be able to rev out to 7000RPM, with peak power at ~6250 - is this realistic?

1. Looms / Wiring / ECU

- My RB30DET will go into an Aussie R31.

- I currently have a RB25DE head, but no loom, and I am unsure about sensors.

- RB30E loom ? Useless?

- RB30E ECU - I would presume useless?

- I have an opportunity to buy an RB25DET loom & ECU, however I understand the RB25DET ECU is not re-programmable - can it be used to run in the car? Can it be used past that at all!?

- Does this mean you can still use topfeed injectors like if you had gone RB20?

- I will go the PowerFC .. I understand an RB25DET suited one is easier to come by than the R32 model .. ?

- With the RB25DET loom, in the R31, will all my electrics function normally?

In short ---> Do I buy the RB25DET loom / ECU?

2. Valve Springs

- I understand RB25DE valve springs need replacing.

- I have been offered GTR valvesprings, which I was keen on until ...

- SydneyKid stated he replaces the valvesprings on RB26's as well! Now I'm very confused! I navigated the website you linked us to but it had nothing but a PDF containing info about "soft springs".

In short ---> do I buy the RB26/GTR valvesprings (new - set of 24??)?

3. OIL PUMP! (This has been driving me CRAZY)

- SK you're saying we should stick to RB20/25/26 oil pumps due to them being designed for higher revs ..

- Would a new RB30ET oil pump be a better trade off than a used RB26 or RB25 oil pump? I understand you keep suggesting GTR pumps, but an early one is going to be 15 years old, and a late model GTR pump will need an adapter ...

In short ---> Do I buy the new RB30ET oil pump over a second hand GTR?

4. CAMS

- There is talk about cams, and Tomei Poncams and such, and RB26 cams (especially from SK).

- How would a set of RB26 cams influence the power delivery? With the change in profile would you be looking at peak power moving towards 6000RPM?

In short ---> Would a set of RB26 cams be a worthwhile 'on the cheap' addition to the buildup?

5. Turbos / Housings / Boost controllers

- Why is everyone talking about getting a bigger exhaust housing so as to stop boost coming on so early and traction issues?

- Surely this is the sledgehammer approach? Why not just dial down the boost with a boost controller, and thus not sacrificing response?

---> This is just general knowledge. Although SK seems to have made some side comments re: this, everyone else seems to talk about how "OH THE VL GUYS SAY THIS" and "OH NO THE TRACTION" that.

Thanks so much guys! I'm going to get some sleep now that its after 4AM, so I'll be able to work to pay for all this.

Edited by MarkE
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Hi guys,

Currently working on my own rb30 hybrid so i thought i might runs some stuff past you guys to see what you think.

So far i have my old rb30 complete engine ripped into ten million pieces, the block is acid dipped then having a bunch of work done to it (rehoned, o ringing... etc) now i was wondering is it viable to use the standard rb30 sump?

Also im planning on using a r32 rb26dett head (am able to get the entire engine dirt cheap :P) and was wondering if anyone has done this? I was told by a reliable source that using the r32 rb26dett head screws the CR ?! He thinks arias make a set of pistons for this application but i thought before i go getting the pistons i would run it past you guys.

Lastly if anyone has done the rb26/rb30 conversion would they possible be able to pm me or post in here a dyno graph?

Thanks heaps.

Edited by DORIFUTO_The Future
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I am using the std RB30 sump.

The rb20/25 sumps require a little mod in order for the crank not to hit the fins when it swings past.

I will eventually pull the motor out and either get my std sump modified to prevent surge etc or fit up an aftermarket one. It really depends on what I can get the std. one modified for at the time.

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I have read this thread a few times before, but have gone over it tonight after having done lots more browsing around the place, and I'm up to about page 85.

I have a few questions, related to purchases I either need to make or not make, tomorrow.

So you get some perspective on where I am coming from I'll give you a brief rundown.  I'm a first year Psych/Law uni student, working in retail, and I'm trying to put together something affordable yet relatively quick.  A 'freshened' RB30E bottom-end and 'freshed' RB25DE head, running ~250KW@RW.

I'm aiming for what SydneyKid got in his original RB30DET build.  If you could induldge me in a more detailed explanation of what you did all those years ago, in terms of the work you did to prepare the block and head and which parts were new/second-hand, and which were serviced or just used as-is, that would be OUTSTANDING.

Instead of the T04 turbo, maybe something more modern, such as a GT3040?  Ideally I'd like it to be able to rev out to 7000RPM, with peak power at ~6250 - is this realistic?

1.  Looms / Wiring / ECU

- My RB30DET will go into an Aussie R31.

- I currently have a RB25DE head, but no loom, and I am unsure about sensors.

- RB30E loom ?  Useless?

- RB30E ECU - I would presume useless?

- I have an opportunity to buy an RB25DET loom & ECU, however I understand the RB25DET ECU is not re-programmable - can it be used to run in the car?  Can it be used past that at all!?

- Does this mean you can still use topfeed injectors like if you had gone RB20?

- I will go the PowerFC .. I understand an RB25DET suited one is easier to come by than the R32 model .. ?

- With the RB25DET loom, in the R31, will all my electrics function normally?

In short ---> Do I buy the RB25DET loom / ECU?

2. Valve Springs

- I understand RB25DE valve springs need replacing.

- I have been offered GTR valvesprings, which I was keen on until ...

- SydneyKid stated he replaces the valvesprings on RB26's as well!  Now I'm very confused!  I navigated the website you linked us to but it had nothing but a PDF containing info about "soft springs".

In short ---> do I buy the RB26/GTR valvesprings (new - set of 24??)?

3. OIL PUMP! (This has been driving me CRAZY)

- SK you're saying we should stick to RB20/25/26 oil pumps due to them being designed for higher revs ..

- Would a new RB30ET oil pump be a better trade off than a used RB26 or RB25 oil pump?  I understand you keep suggesting GTR pumps, but an early one is going to be 15 years old, and a late model GTR pump will need an adapter ...

In short ---> Do I buy the new RB30ET oil pump over a second hand GTR?

4. CAMS

- There is talk about cams, and Tomei Poncams and such, and RB26 cams (especially from SK).

- How would a set of RB26 cams influence the power delivery?  With the change in profile would you be looking at peak power moving towards 6000RPM?

In short ---> Would a set of RB26 cams be a worthwhile 'on the cheap' addition to the buildup?

5. Turbos / Housings / Boost controllers

- Why is everyone talking about getting a bigger exhaust housing so as to stop boost coming on so early and traction issues?

- Surely this is the sledgehammer approach?  Why not just dial down the boost with a boost controller, and thus not sacrificing response?

---> This is just general knowledge.  Although SK seems to have made some side comments re: this, everyone else seems to talk about how "OH THE VL GUYS SAY THIS" and  "OH NO THE TRACTION" that.

Thanks so much guys!  I'm going to get some sleep now that its after 4AM, so I'll be able to work to pay for all this.

I had the same aim as you.....250 rwkw using a "cost effective" package.

1. Get the loom associated with whichever head you are using. i.e. R32 or 33.

2. Valve springs in n/a and turbo r33's are identical. r32 n/a are softer aperantly.

3. Definately stick with a twin cam pump. I used a S1 r33 pump which did not need a collar.

4. Cams not sure on. I'm using standard r33 with vct. So far it has made 220rwkw @ 11psi.

5. I'm using a GT3040 with a 0.82 rear (it's in a VL). I have 11 psi at ~2700rpm. With the 3.45 diff, 1st gear is tyre smoke, but i generally don't have traction issues in 2nd with 235/45 17's. I'm sure with a skyline diff 2nd would be tyre smoke aswell!

Bottom end and head are both stock. Once the boost is upped to 14 - 15psi it should make 250rwkw.

Hope some of this helped!

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I find it interestering the DET harmonic balancers have been reported to have harmonic issues (break oil pumps) up around 7500rpm.

The VLT blokes on the other hand with their SOHC harmonic balancers tend to have issues up around 6500rpm.

If you really want to rev it, run an aftermarket harmonic balancer, ATI I've heard works.

Obviously i'm not talking from experience. So nothing is concrete. :P

Edited by Cubes
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never heard of an RB30ET having oil pump or balancer issues, especially not at 6500rpm? some of the drag guys go up around 7500 with the SOHC head but you can bet your titties they're not running standard oil pumps. haven't heard of many of them changing their balancers either.

i guess if you're going to rev the bejesus out of it for a sustained period of time frequently, you've gotta think about these things. but for a street driven car it's just not an issue IMHO.

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It really depends how the heads are from factory.

My head apparently had quite good valve seat pressure where as a friends (bl4ck32) rb25de head required shimming.

His valve seats were noticably receeded in the head.

But generally its some where up around 15-17psi.

Bl4ck32 is now running 16psi with no issues.

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Okay i think i have the VCT problem sorted. Here goes:

Looking from the front of the engine, there are two oil holes for the front cam bearing. The one on the left is connected to the high pressure oil feed which normally comes in from the VCT oil line in the block. Since it's now welded up, that feed is not getting any oil whatsoever. This feed is definately NOT connected to the high-pressure feed rail which supplies all the lifters on the inlet side. I thought it was, but on closer inspection it is definately not. The front cam bearing relies on this block feed to supply it with oil and not sieze.

The second hole (on the right) is connected to the first hole via the cam bearing face, which has a trench milled in it. This hole drains down into the head, to be later returned to the sump by whichever means possible. It only does this when the VCT solenoid is powered OFF. When it is energized, the solenoid blocks this drain and high pressure oil is forced into the end of the cam where the VCT gizmo is located which then activates it.

So what does this mean? It means if you don't re-feed the first oil supply then your bearing will run dry and probably sieze. The good news is there is an easier way out of it than an external line.

looking at the head front-on, there's a small copper plug just below the solenoid which the manufacturers used to block off a hole that they drilled in there to connect the oil galleries up due to a small offset. The plug can be drilled out pretty easily. Luckily, it's directly in line with the high pressure gallery which feeds all of the lifters! So just drill a hole of comparable size to the oil supply hole through there to connect it up to the high pressure gallery and feed it with oil.

There's one more problem though, doing this will drop the oil pressure to that gallery dramatically whenever the VCT solenoid is off. NOT GOOD! you can grub screw up the oil drain but this will turn the VCT solenoid on the whole time, also not good! What you will need to do is either replace the inlet cam gear with a non-VCT one or block up the oil holes IN THE CAMSHAFT ITSELF which allow the oil into the front of the cam. This will stop oil getting to the VCT lobe altogether.

I'm going to go out now and pull the gear apart and see if there's an easy way to disable it from the inside. otherwise i'm going to get a non-VCT inlet cam gear. I think this idea is a lot neater, easier and cheaper than making up an external line from somewhere else to supply the VCT again.

So yeah, don't try and run an RB30DET with the VCT gallery just welded up, you need to get oil there somehow!

p.s. Luke thanks for telling me this, i went over the whole thing again and figured out you were right. lucky bastard.

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Okay i just did all this and it will work just fine. drill out the brass plug just below the cam, then insert grub screws into each of the holes in the bearing supply face. Drill a restrictor through the one which now supplies oil (same size as the other ones in the cam tunnel) and leave the other one blank.

There is an easy way of disabling the VCT too, just take the big bolt out of the end of the cam and weld a plug in to one end of it.

Viola, no VCT and a nice high pressure oil supply to the cam bearing.

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Hi guys,

For those that had to drill and tap there own block's. What size fittings did you use for your oil return? May as well tell me all of them while your at it.

But mainly looking for the oil return as i think i have spotted a nice supply of suitable fittings at work :)

Thanks for your time,

Scribble

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^^ i got that from a few post's before but the fittings i have seen in various pictures reduce from that size to something smaller for the turbo return pipe to bolt to. Thats what im after really so i dont get anything to big or too small on the side the turbo connects to.

Thanks

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ok, bottom end is fully rebuilt and i now have the head (rb25de non vvt) Here's my shopping list for sometime this week, if there's anything there that looks wrong or not needed etc please let me know.

1. Series 1 RB25DET oil pump (dunno where to get this apart from nissan - big$$$)

2. Rb30e water pump

3. Timing/cam belt

4. Rb30e genuine metal head gasket

5. Rb20 thermostat and thermostat housing

6. Rb25 VRS Gasket kit

Cheers guys!

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