I started torquing it up in stages and the bolt reached it's yield at 350nm. After that it kept turning. Luckily I had a spare bolt and changed it out and this one torqued up to 400nm. That's Really F***en Tight! I used ARP lube on the first one and the second one went in dry but I assume there was still lube inside the crank. Any thoughts?

Im looking at fitting a set of camtech 272 duration 9 lift cams with tomei springs 

Does anyone have any experience with these cams and also what changes should i expect from.the car power and delivery wise.

Are there any other drop in cams worth looking at

• will a rb25 wiring loom need much changing apart from the e36 side of things? (ill be ordering a e36 rb25 loom)
• for a 25 box i just need a 25 slave and starter?
• is haltec the only real way to go ecu wise or could i nistune a 25 ecu
• what power can stock studs handle
• is there a reason i shouldnt use a n/a 25 head and ecu if i dont want to turbo it straight away

above all that i dont want to make big power straight away just want it to be usable 

This will go into a ER34 which currently has a (tired) RB25DET NEO; but I won't be touching the engine that is in it until I have completed the new engine.

This will very much be a daily driver/gokart and would be quite happy making 350-400rwkw (even that's overkill), full boost at or around 3500rpm (max) would be my preference - I'm considering something like the EFR 8374 or perhaps the next step down.

I've read many of the threads and while there is some talk about these pistons I still have not managed to find a definitive answer for my preferred choice of piston material, 4032 pistons - smaller tolerances - ideally for the longevity, (slightly) improved detonation tolerance (over raw cast) and the fact that I would rather bore out that 25+ year old bore and replace the 25+ year old pistons, it seems logical to go with brand new pistons/rods... well aware of the general consensus that that the stock pistons and rods are good for 300rwkw.

For rods I will probably go with spool import conrods, for pistons it appears only Wossner and Mahle do a piston in 4032.

So my question being, using the RB25DET Neo head (we'll have to assume the head cc at this stage) and having a preference for around 8.75 - 9.0:1 compression ratio - does anyone have any recommendations on exactly which pistons would be required and exactly what work would need to be performed to the block - ie deck height (more so I know what I'm in for, ideally I would like to not have to mess with the deck height significantly more than a skim if avoidable)

Looking at the various catalogs it's very confusing in so much as I often cannot even find the pistons being listed on various retailers sites in the manufacturers catalogs.

I've just taken delivery of my RB30 bottom end. Now it was going to be 25 head, but i changed to 26 head. The motor came with ACL RB25DET pistons 6MKRY9603 's.

Now i just spent abit of time on this site, http://www.csgnetwork.com/compcalc.html

All the values are easy to get, except the deck height . So i actually measured it myself at .254mm (below)

So these are the values i used below.

6MKRY9603

Bore 86.5mm

Stroke 85mm

Gasket Bore 87mm

Gasket Thickness 1.2mm

Combustion Chamber CC's 64cc (average of what i have read on here)

Piston Dome CC's 11.5cc (off ACL website)

Piston Deck Clearance .254mm (Measured)

Gives a comp ratio of 9.17 : 1

If using the RB26 ACL Piston

6MKRY9604

Bore 86.5mm

Stroke 85mm

Gasket Bore 87mm

Gasket Thickness 1.2mm

Combustion Chamber CC's 64cc (average of what i have read on here)

Piston Dome CC's 16.3cc (off ACL website)

Piston Deck Clearance 1.254mm (Measured + 1mm as ACL lists the RB26 1mm lower COMPRESSION HEIGHT)

Gives a comp ratio of 9.03 : 1

NOW ..... what i wanted to know is..... the comp ratios are very close, so either would suit, however the 1mm lower deck clearance on the rb26 piston, is this for extra valve clearance of high lift cams in the 26 ??

Will the 25 piston be ok in my motor with the 26 head and 260-280 10.8mm lift cams ?

Hopefully someones been down this road.

Thanks

Gary

Would you do the 30 if the 25 is still running well? 

(25 neo around 350kw)

The bore measures 86.10mm so i thought the gap would of been less.

Can i use RB25 or RB26 oem rings?  and expect the end gaps to be much closer to say 0.35mm?

The final tune will be in a week and I would like to see if anyone can guess the results

The run in tune at 15psi was 314awkw on 98 pumps, the car has been built for response, at the final tune the cams will be dialed in for response.

Builder Is CRD

Parts

RB26 Head

RB30 Block

Nitto 3.2 Stroker kit

UE 260 10.8 custom cams, springs and retainers

Supertech 1mm OS Valves

PT6262 CEA turbo

ID1300 injectors

Splitfire pack

Haltech R34GTR ECU and flex fuel sensor

Walbro 460LPH pump ( not sure if this will do the job)

Custom 3.5" exhaust

Thats the best I can give you

Have a guess at

20psi on 98 and E85

25psi on 98 and E85

My Guess , well I would like

400awkw and 435awkw

425awkw and 465awkw

Please do not put shit on me, just guess or go elsewhere

Feel free to delete this post if it's already been asked but I cannot find anything on google showing how people calculate the oil clearance without bearings installed. I have an idea of how to, but I just need someone to confirm my calculations for my bearing/oil clearances before I buy the bearings. This is my first ever build and first ever RB30/25. I've never done something like this and I'm trying to do as much labour as I can before I send it to the machinists to save $$, so bare with me.

I have measured the journals with a micrometer and mains + big end tunnels with a bore gauge (without bearings installed). I'm going to be using ACL Race bearings for mains and big ends. I need to know what bearings to choose for my desired oil clearance.

Now here's the thing. By looking at the ACL RB30 bearings spec page, the thickness of 1 standard big end bearing shell is 1.503mm. Am I correct?. And 1 main shell = 1.827mm.

So, if I were to go with a 0.025 oversized bearings, the thickness of one 0.025 big end bearing shell would be: 1.503 + (0.025/2) = 1.5155mm. Correct? Because it's adding 0.0125mm on each shell to make the diameter of the 2 shells 0.025mm bigger right? And thickness of one 0.025 main bearing shell would be 1.8395mm.

Ok, so calculating oil clearance would be tunnel OD minus the thickness of 2 bearing shells, then minus the crank shaft's ID to get oil clearance right?

So, for example my #1 main tunnel OD = 58.682mm.

If I used standard main bearing, the thickness of 1 shell is 1.827mm.

My #1 main crankshaft journal ID = 54.962mm.

So calculating the oil clearance would be 58.682 - (1.827x2) = 55.028 - 54.962 = 0.066mm of oil clearance which equals to about 2.5 thou.

If I were to use 0.025 oversized then I would calculate it like: 58.682 - (1.8395x2) = 55.003 - 54.962 = 0.041mm of oil clearance (1.6 thou).

So calculating all my oil clearances using standard bearings on the mains would be 0.057mm to 0.077mm (2.2thou to 3thou) of oil clearance.

Big ends oil clearance using standard bearings = 0.032mm to 0.053mm (1.2thou to 2thou) 

Calculating oil clearance using 0.025 oversized bearings: Mains = 0.032mm to 0.052mm (1.2thou to 2thou). Big ends = 0.007mm to 0.028mm (0.3thou to 1.1thou).

Calculating oil clearance on big ends using HX (thinner bearing shell thickness of 1.49mm) would be = 0.058mm to 0.079mm (2.3thou to 3.1thou).

Another question I have is what would be the best oil clearance for an RB30/25DET Neo that will only be used for street use with about 300kw (max) with a crank collar and RB25neo oil pump limiting the revs to 6500 or 7000rpm (with the correct oil restrictions in block). I might shim the oil pump spring to give it more pressure if needed. My goal is just a responsive and reliable streeter engine that will last years.

I've read somewhere that someone qouted Qubes saying that he recommends 2.5thou oil clearance on the mains and 2.2thou on the big ends for RB30s. Can someone confirm this?

So should I go with standard ACL Race bearings on the mains and standard on the big ends or HX on the big ends (3.1thou max though?). 

Thanks.

I can feel it definitly with my finger nail. I reckon it's about 0.2 or .1mm deep probably. I'm worried now. I want this build to last years as it will be my daily streeter. Will this cause damage to my rings and/or cylinder bores?

Well yesturday i picked up a RB30 for my conversion into my R33.

I will be using my RB25DET head on the RB30 block. So i started stripping the motor down, pulled the crank, pistons, girdle, oil pump, welch plugs & everything off the block. Now the RB30 block is going to be Acid dipped/cleaned and machined out a further .10 ontop of the .15 that it allready has. (total of .25)

Looking around on these forums i noticed a couple of threads of people spending $800 - $1200 on RODs! I pulled a piston out yesturday of the RB30, removed the gudgen pin and looked at the rod...

I then walked over to my old mans 900HP, 7 liter, 454 Big block chev (Also in peices on the floor) & compared rod sizes. Width of the Rods, SAME!.... Side wall strenth & Height SAME!!. Only noticable diffrence is that his are slightly longer. (witch in fact would make them weaker than mine because my rods would have a higer pressure tolerance) I will leave the rest for you too decide when its time for you to do a rebuild.

Anyways i am now at a stage were i am looking for pistons, i am not intrested to here anything about forged pistons. Alot of people arent aware of the cons about forged pistons, such as the amount of slop that a forge piston has (Clerance properties between the bore and the piston, & heating + cooling tolerances).If you guys all wanted to run 9 sec passes and were looking for no more than 100K then i would suggest running forgies. not for mild street cars.

Now, has anyone tryed using Thermo-pudic pistons (not sure on spelling)? i havent done too much reasearch into these pistons, but heard that it a very strong alternavtive to running forged pistons. And are still capable of running very high HP (600+). Some of the advantages of these pistons so far are that there heating & cooling properties closly match the stock pistons, and they are a very snug fit in the bore (prevents slapping up the bore on cold starts, unlike forgies that have to become warm then expand to provide the snug fit) This inturn reduces engine (cylinder) wear and will provide me with the drivability & performance that i am after.

Has anyone used these pistons or know of someone that is using them that has problems?

Basicly i am after so critism on the pistons, if there is any?

Thanks.

Edit : new host of the RB30 DOHC guide hosted by Titan

RB30 DOHC Guide. (Click me)

rb30_dohc.zip

I see some people say to just drill and tap into the gallery on the head, and others weld a -3 fitting. Trying to figure out the best way to go. How thick is the aluminium before you get to the gallery? If its thick enough i guess a tapered thread is fine but wasnt sure if a weld on fitting would be better. 

Does anyone know what the thread and pitch size is for the Heater hose (return I think?) fitting/attachment that threads into the block. I assume all RBs have the same thread on these?

I've uploaded a pic of it (block is upside down). It sits on the intake side near the top rear of the block. I'm doing up a RB30/25. As we all know, you have to swap out the RB30 one and put the 25 one in there because the 25 has only 1 barbed outlet for the heater hose. I had to grind the old one out of the RB30 with a dremel because it was rusted on there so badly, and thinking the RB25 one will be the same, I just want to get a brand new one. If anyone could tell me the thread and pitch size of this fitting (or even better, the Nissan part number!) that would be much appreciated for me and everyone els looking for this in the future, because I've tried googling, and googling and nothing.

Thanks!

First of all, do anybody in here know if there are different deck height on the RB30 Blocks, like different models ?

Reason im asking is that I have a block here that has a 226,5mm deck height, and what other people tell me is that stock is 230.5mm

im looking for a new block, since this block keep messing things up and going out of straight.

So any info is appreciated, and let me know if someone has anything available.

Kenneth

However the Rb26/30 GTR conversion has a few more bits and peices to make this process work.

How about we have a thread specific to the GTR conversion that covers:

* the Rb26dett head build up to suit

* Forged piston selection Vs compression

* Sump adaption and oil pick up.

A step by step pics based guide for DIY would be great to eventually have too, for anyone thinking of doing this in the near future to consider adding to this.

Saves wading through the hundreds of posts.

Rb30 series 2 engine from a skyline r31

Strippped down measured cleaned tested. Bored to 86.5. Decked oil restrictors fitted tentioner relocated

Crank was measured up balanced and fitted with a collar and grub screwed

Ditched the standard rods and pistons and bought cp flat tops with spool rods was going to keep the rods a peen them but was told by the time you do all that and also have to line hone them its better to buy the spool.

New water pump, new N1 oil pump with relived pressure not fitted yet 

Stainless core plugs instead of the copper ones 🙄

Thats where im at for now waiting on work for the head and getting enlarged sump made up here are some photos 

have been driving for 1700kms now, with no real adverse affects**

so, welcome all to my 30mm subframe drop thread.

any questions you have, throw them in here, and I will try and answer as quickly and honestly as possible.

please keep in mind, I doubt this is legal.

these havnt been "engineered" yet.

I will try one day, but havnt had the time/money associated to do so.

I will try and include any info I can that helped/hindered myself when doing this.

the spacers I used were made by a race/rally car engineer, and calculated that the stud the mount to would snap before the shank nut.

so, here we go....

Looking to start a rb30det project since the bottom end has died in my rb25.

Motor is a series 1 r33 rb25det.

Have done abit or research and am armed with the twin cam rb30 guide.

Chose to go the rb30 route due to overall cost involved, and cubes are good

I have a decent budget but am not overly rich so seeing if I can save some moneys.

Current things I have bolted to the rb25 are:

kkk k26 2670 (330ps rated) with external wastegate, 480ccc injectors,z32 afm, exh, intercooler,

Will be using stock cam's, but going to using greedy/jun or copy inlet manifold to make sure I dont get into trouble with the extra deck height in the cefiro.

Now,

I need some opinions, especially from the guys who are running standard bottom ends.

How long have they been running for, with what modifications and what boost?

I plan on upgrading to a larger k26, looking for 250~ rwkw's

Possible to get away with using some new cast ACL or similar brand pistons for the power Im chasing?

Its a drift car, but not daily driven, reliability is a must.

Or just buy (insert brand name) forged pistons for peice of mind?

Dont mind spending the extra on forgies, but any money saved is a bonus.

Thanks for your time

Dan.

Hi guys sorry to ask about this as I thought I had all the information needed about the rb25 head on a rb30 block but I stumbled across a thread on here where somebody stated that you had to restrict the new external feed for the oil. is this true? As I don't see why as the oil going through the solenoid is restricted by the solenoid itself because of the holes it feeds through. And the rb30 doch does not meti9n anything about a restrictor in the vct feed. I know about restrictor in the block for the head feeds but not the vct.

Any comments would be great

I seem to have a re-occurring exhaust cam/lifter wear problem on my RB30/26 and was wondering if anyone else has seen this ?

Originally cams were Kelford 182E's with Tomei lifters and after 500 miles or so the engine started making a increasingly loud ticking noise. After pulling the cam covers off I found some of the exhaust cam lobes and liftere were showing signs of wear. One lobe and lifter in particular was very bad (near cap 5). The lifter had actually mushroomed as can be seen in the pictures below.There seemed to be plenty of oil in the cam covers so I was advised it may be a material hardness issue on the cam or lifter. The inlet cam/followers were ok.

The cams were replaced with Tomei cams/lifters and after around 2000 miles the same wear is apparent on one of the new exhaust cam lobes but in a different position this time - lobe/lifter 2. Again plenty of oil seems to be up there but I'm wondering if this must be some sort of oil supply issue to the exhaust cam area. Again the inlet cam is fine. Checked valve clearances and most are within tolerance still apart from number 2 exhaust lobe/lifter which now has a big clearance and rather than mushrooming it looks like the lifter now has a slight bowl in its top.

The engine has a N1 oil pump with wide drive collar and blocked of rear feed to head and Tomei front oil restrictor to head. Plenty of oil pressure measured in the block.

Anyone seen this before ?

Cheers 

Stu

Just wondering if anyone has any review on Kulig Engineering Rb30 awd adaptor, there is a guy selling one near me. I can't seem to find any details or information in my Google searching 

Here is there site http://www.kuligeng.com.au/autoengineering.html

Thank you for the help 

Rob