R33 Rb30 Conversion

[webbey]

Hey guys i am looking at an RB25 head atm that has already been modified to suit the RB30 it has 820cc injectors and has made 680hp it has done 1500km and it has all been track time, now i do not have enough experience in RB25 and stuff to know whether that is a lot of K's or whether or not to just do my own head up because i do not want to buy it and have it shit itself a few hundred K's later, please no abusing me i just want some positive criticism cheers.

[SirRacer]

buy it!

[webbey]

So you reckon it will be ok to buy >? I will save myself a couple of K if i do like i said is 1500km to much for a head that has been on track ?

[shanef]

So you reckon it will be ok to buy >? I will save myself a couple of K if i do like i said is 1500km to much for a head that has been on track ?

itll be fine on the priviso that it hasnt been overheated

get it checked for warpage, flatness, valve seat sealing, valve guide clearance etc etc

[SirRacer]

You typically cant go wrong on a head thats 1500kms old considering most people are quite happy to run heads with 50+000 kms on the clock

[r_speedfreak_r]

This bit interests me, "r33 gts-t using an rb25 head & rb20 pwr steering pump". Why are you using an RB20 power steering pump? They are older and heavier and have no discernable advantage over the standard R33GTST power steering pump. Which is a straight bolt up.

Cheers

Gary

there was nothing wrong with my r33 pump but while the car was still in pieces we knew that the pump wasnt aligned & i could remember something in the pdf guide about r32's having some advantage over the r33's. i didnt relise it was the bracket not the pump. atm the pump is too far forward and needs to be moved back. Does anyone know if i put the r33 pump back on and use an r32 bracket if it'll line up any better? I'm using a ross gtr balancer btw

[SirRacer]

i find that under high rpm's my rb20 pump release valve seems to stick and i lose power steering

[r_speedfreak_r]

looks like i got my facts wrong. The car is fitted with a 32 bracket using my 33 pump. The ross balancer is a two piece but i cant space out the pwr steering belt ribs becaue of the design. the workshop are gonna try and press on the pwr steering pulley for me.

[Maddo]

hey guys just getting my stuff balanced got told by the guy thats doing it that i need a smaller aftermarket harmonic balancer because of the high revs the engines pull the water pumps break anyone heard of this or is he just taking me for a ride, he has also never heard of one of these engines shiting an oil pump whats your thoughts on this?

[Scooby]

he should stick to balancing.

[GTRgeoff]

Maddo, hard to actually decipher what you are saying but I'll try answer. A little punctuation makes it clearer.

The Water pumps do fail, sometimes without warning. One I saw recently had a chunk of something jam into the impeller so it must have been in the cooling system. The whole front of the housing exploded forward and slammed into the radiator.

The stock balancer is often good enough if you aren't going to try to rev to over 8000. After that I would advise a good HB.

The oil pumps will fail, for many reasons but usually due to having a short pump drive in some early series engines and banging off the rev limiter.

[Bliksem]

Change to a better oil pump than the RB30E unit as it was never designed to flow oil to a DOHC head and turbo. They will potentially give you oil pressure problems at idle... How do I know? I followed the advise of my engine builder and unfortunately kept the RB30E pump following his logic of "if it aint broke dont fix it..." bad move. Im now in the process of installing a brand new RB26DETT oil pump. $266 from Greenline.

[GTRgeoff]

From my research there is no difference between RB26 and RB25 oil pumps. Same part number in FAST and same flow rate. Don't get ripped of by paying for a "GTR" pump.

A pic of the different oil pumps. I will be completing a document soon on some oil pump info for the forum.

[Al]

Maddo: If you plan to do track work, then i would also lean towards getting a ATI balancer. Yes it is under driven, but at high rpm you reduce the risk of damaging water, power steering and the alternator. Also you are going through the expense of building a new engine, why put on the std balancer that has 15yrs of wear and vibration

Just my opinion and the reasons i bought my ATI balancer.

r_speedfreak_r: i can't understand why you'd even consider tampering with the ROSS balancer. They would be designed and balanced to perform the task and any modifications to such a vital component would be very risky. As i stated earlier, you should have no issues reseting the pulley on the p/steering pump.

Geoff: Nice work mate.

Hope QLD is treating you and your Mrs well. All the best.

Just a progress pic

[TiTAN]

Just a progress pic

Genuine Greddy plennum (i recognise the bag of bits on the windscreen)

Q45 Throttle body.

By the looks of it nismo 740cc injectors?

your wallet must be crying out in pain

[Bliksem]

From my research there is no difference between RB26 and RB25 oil pumps. Same part number in FAST and same flow rate. Don't get ripped of by paying for a "GTR" pump.

A pic of the different oil pumps. I will be completing a document soon on some oil pump info for the forum.

This is not the case in my copy of 'Fast'

RB25DET Part Numbers:

RB26DETT Part Numbers:

The Workshop Manual also states RB26DETT Oil pressure is slightly different:

Why the pressure for the RB26DETT is higher at idle but lower than the RB25DET at RPM I'm not sure, extra turbo, different relief valve spring?

[GTRgeoff]

I haven't got it running at the moment but I was looking in a completely different area with Funkymonkey. It was pretty descriptive.

Springs are linear so it would simply be because a 26 idles faster, but has less oil supply to the head. I've had them both apart, overlayed the gears and they were the same. I didn't have time to test the spring rates but they felt the same.

[Bliksem]

Those screen shots are from part's master.

You copy the part number into there and do a search and it will show you if that part is used on any other vehicle... Perhaps there are differences in the pump housing.

Note the attached pic, top RB26 pump, bottom N1:

Unfortunately I ant find a pic comparing RB26 vs RB25, but aleast this shows there are other differences apart from gear width.

Edited February 23, 2008 by MintR33

[Al]

Genuine Greddy plennum (i recognise the bag of bits on the windscreen) - yes

Q45 Throttle body. - yes

By the looks of it nismo 740cc injectors? - no: SARD 550cc

your wallet must be crying out in pain - YES!

[GTRgeoff]

As I said, I could find no differences whatsoever. Not to say I didn't miss something in the housing, but nothing there makes any difference to the operation.

The N1 though is a common enough failure on drag cars banging on the rev limiter. The peaks in the much narrower area of the outer gear ring are typical stress concentrators. Add to that the material for the N1 pump gears has been hardness tested against the stock oil pump gears and was found to be much harder, therefore much more brittle. It is a compromised design which is unfortunate.