RB 30 /25 BUILD

[Chev R]

Good Day Guys

Chev R here from SA have not posted for a while since my car was down. Started an Rb 30 build and need some input and guidance on how to make this budget build work and bullet proof if i can say that please

I had Rb 25det in my car but unfortunately detonated number piston ringlands and spun number 6 big end bearing. So i have been reading up on a substantial amount of info regarding the Rb 30/25 build. I have also down loaded the Rb 30 Dohc guide.

I have started the process of my build and this is what i have done and bought so far"

Cylinder Head:

• Rb 25 det Vvt 
• Ported and flowed 
• Rb 26 valves , quarters , retainers , valve springs and solid lifters 
• Rb 25 det cams cut 270
• Head is solid lifters and solid cams

Block / Sub Assembly:

• Rb 30 series 2
• Drilled to 86.5 due to sleeves not measuring same size through
• Oil Galleries Drilled to size of my Cometic head gasket
• Block has been decked 
• Tension er being drilled and moved 
• New Rod bushes 
• Complete rotating assembly balanced
• Acl Mains and Big Ends
• Rod Bolts Arp 202-6007 for Rb 26 taken. Was going to take Sr20 Arp 202-6005 but when i went to buy we measured both bolts and they measured the same only difference was the length of the bolt rb 26 being slightly longer. Opted for 26 as it comes with 12 as apposed to 16.
• Block will be o ringed 
• Rb 25 det 1.2mm cometic head gasket 
• Extended Crank Collar fitted 
• New Timing Belt
• Using Rb 25 Det Oil pump that will be flowed
• New Stock pistons with Hastings Rings

Other Parts :

• 60-1 T4 Turbo 
• Bosch 750 cc Injectors 
• 40mm Waste gate 
• 76mm exhaust 
• Full Boost SA turbo branch 
• x 2 Greddy blow off valves 
• 3 button clutch 
• Spitronics Mercury 2 Engine Management 
• 76mm throttle body 
• Catch Can 
• Vacuum Block 

 

What i am after is with what i have so far what do you guys think would be a good Hp number i can aim for? I have read some guys doing 500hp and others in access of 600hp. Please share your experiences?

Also i have read about rods being short peened and polished to make them stronger. My question is is this worth wile doing and will it assist to make them stronger? If so i will have it done while the motor is apart.

I am a skyline guy and here in SA everything is almost 2jz and i guess with reason but i guess i wanna prove a point that RB'S also make power you know. I will be saving for forge pistons and rods abit later will be getting CP's.

I would appreciate your expert advise and guidance please.

Should there be anything i may have left out please make mention and all input is appreciated

Thanks 

 

[PLYNX]

Hey Man;

That all looks pretty good

Just a few things I've spotted in your build;

-Do some research on how much power has been made with stock cams on the RB25 head ! I think you might be over investing for the power you want to make. Some drop in cams for the on the hydrolic set up will save you a bunch of money here

-O-ring the block - if your going to run a cometic head gasket that should be fine.- the alternative is to run a copper head gasket with the o-ringing. Coupled with this, save your little lunch money and get head studs for better clamp pressure.

-As to the rods crack testing, shot peening and magnafulxing them will increase their strength and has been a tried and true method for stock rods since Noah was a boy.

-And lastly, again save your lunch money and drop in a set of forged pistons,  don't do it twice ( the money you will save on the head set up may even allow the rods you are after )

Hope this helps

 

 

 

[KiwiRS4T]

Don't know anything about your turbo or ECU but you look to be set for north of 400KW

Re oil control  consider putting a couple of half inch plugs in the sump (above the oil level ) in case you need them later.

Also people will suggest say 1200 injectors (do it once).

Why two blow off valves?

Should be great when done!

 

And what Plynx said - head work looks like overkill but if you have already done it....

And yes forged pistons but rods will be fine if treated as per above.

[Chev R]

7 hours ago, PLYNX said:

Hey Man;

That all looks pretty good

Just a few things I've spotted in your build;

-Do some research on how much power has been made with stock cams on the RB25 head ! I think you might be over investing for the power you want to make. Some drop in cams for the on the hydrolic set up will save you a bunch of money here

-O-ring the block - if your going to run a cometic head gasket that should be fine.- the alternative is to run a copper head gasket with the o-ringing. Coupled with this, save your little lunch money and get head studs for better clamp pressure.

-As to the rods crack testing, shot peening and magnafulxing them will increase their strength and has been a tried and true method for stock rods since Noah was a boy.

-And lastly, again save your lunch money and drop in a set of forged pistons,  don't do it twice ( the money you will save on the head set up may even allow the rods you are after )

Hope this helps

 

 

 

Hey Plynx 

Thanks for the response.

I have invested in having the head done while the motor was still the Rb25det so not spending on it at the moment has been done.

Noted on the o ring of the block as I have a cosmetic currently will probably look at the Head studs instead.

Rod testing etc will have done not alot of guys have done this just confirms for me?

As for the Forge pistons and Rods I have gotten pricing on it. Unfortunately the SA rand is f....... if can say that think at this point Rand to Dollar is 15. So guys that import charge a fair bit. Rods and Pistons should cost me about R30k SA rand. I need to save up a little to get there.But in my plans for sure.

Thus is valuable input thank you very much.?

 

[GTSBoy]

You can spend the hours on the rods instead of Rand. Back in the bad old days, I spent many hours polishing ALFA rods and other things that it wasn't worth spending cubic $$ on new billet stuff for. And in those days, pre-Chinese manufacturing, anything aftermarket cost waaay too much anyway.

[Chev R]

7 hours ago, KiwiRS4T said:

Don't know anything about your turbo or ECU but you look to be set for north of 400KW

Re oil control  consider putting a couple of half inch plugs in the sump (above the oil level ) in case you need them later.

Also people will suggest say 1200 injectors (do it once).

Why two blow off valves?

Should be great when done!

 

And what Plynx said - head work looks like overkill but if you have already done it....

And yes forged pistons but rods will be fine if treated as per above.

Hey KiwiRS4t

Thank for your reply

The Turbo is a hybrid if I can call it that Garret 60-1. Are 70 Compressor and Ar 68 Exhaust side and T4. Similar to Gt35. Management is one of the brands we have here. 400kw much than I ever imagined but noted.

Are you able to elaborate a little more on the half inch plugs in the sump please?‍♂️

One seized at some point bougt a new one and managed to fix the other so just fitted both?‍♂️

THanks and noted all info will surely speak to my engine builder?

[Chev R]

9 minutes ago, GTSBoy said:

You can spend the hours on the rods instead of Rand. Back in the bad old days, I spent many hours polishing ALFA rods and other things that it wasn't worth spending cubic $$ on new billet stuff for. And in those days, pre-Chinese manufacturing, anything aftermarket cost waaay too much anyway.

Thanks GTSboy will be having rods done?

[GeeDog]

13 hours ago, Chev R said:

Chev R here from SA

 

33 minutes ago, Chev R said:

SA rand is f.......

South Africa then - SA on an Australian forum is usually taken as being South Australia.

[PLYNX]

GTSboy Ive done the same over the years as well running the old Holden inline red motor 6 up to 7000rpm on preped star fire rods and just over 8000rpm on preped VW Passat rods so it can be done.

You just need to get rid of the excess casting slag and weight from the rod then prep them the rest of the way.

I Ive got a set of RB30 rods half preped some where which I stopped cause here in AUS the after market rods worked out better.

Have you looked into maybe a set of after market 6 inch Chev rods ?

They can made to fit with a small amount of work !

Research Research Research !

[Chev R]

24 minutes ago, GeeDog said:

 

South Africa then - SA on an Australian forum is usually taken as being South Australia.

Hey GeeDog

Noted will make proper reference ?

[Chev R]

25 minutes ago, PLYNX said:

GTSboy Ive done the same over the years as well running the old Holden inline red motor 6 up to 7000rpm on preped star fire rods and just over 8000rpm on preped VW Passat rods so it can be done.

You just need to get rid of the excess casting slag and weight from the rod then prep them the rest of the way.

I Ive got a set of RB30 rods half preped some where which I stopped cause here in AUS the after market rods worked out better.

Have you looked into maybe a set of after market 6 inch Chev rods ?

They can made to fit with a small amount of work !

Research Research Research !

Hey Plynx 

Will be taking the rods to Fullrace here in South Africa a engineering shop.

To be honest I have not looked at the v8 rods but I have seen a few topics that made mention of it.

True and everything I have done is through reading and research on what guys like you have done.

Still researching thanks

[GeeDog]

Are you planning on using the VCT? You'll need to get head mods done for the oil supply, and also to allow a bit more meat where the RB30 block is different to the RB25 (if I remember correctly a coolant gallery in the block isn't really covered by the head. I might be totally wrong, it's been a few years & I'm not as young as I used to be. I used a machine shop who has done quite a few RB25/30 setups, and was going to recommend him to you, until I realised South Africa.

[Chev R]

1 hour ago, GeeDog said:

Are you planning on using the VCT? You'll need to get head mods done for the oil supply, and also to allow a bit more meat where the RB30 block is different to the RB25 (if I remember correctly a coolant gallery in the block isn't really covered by the head. I might be totally wrong, it's been a few years & I'm not as young as I used to be. I used a machine shop who has done quite a few RB25/30 setups, and was going to recommend him to you, until I realised South Africa.

Hey GeeDog

No I won't be using the VCT my head is solid cams and solid lifters.

Sorry also did not realize but makes sense. Your input is valued 

[GTSBoy]

20 minutes ago, Chev R said:

No I won't be using the VCT my head is solid cams and solid lifters.

Is that because of large duration? Because otherwise they're not mutually exclusive, and VCT is worth a LOT of cam.

[Chev R]

3 hours ago, GTSBoy said:

Is that because of large duration? Because otherwise they're not mutually exclusive, and VCT is worth a LOT of cam.

Hi GtsBoy

Not sure what you mean by large duration can you elaborate? Please excuse my ignorance I am not really a engine builder.

Something I will need to look into I guess

[KiwiRS4T]

Large duration cams is the 270 deg cf stock around 240. VCT would help with making car more streetable and is definitely worth doing.

The sump plugs I suggested were so that if it became necessary you could run a breather to a catch can and a drain back. Polish up your stock rods as you have suggested and just get the forged pistons.

[Chev R]

9 hours ago, KiwiRS4T said:

Large duration cams is the 270 deg cf stock around 240. VCT would help with making car more streetable and is definitely worth doing.

The sump plugs I suggested were so that if it became necessary you could run a breather to a catch can and a drain back. Polish up your stock rods as you have suggested and just get the forged pistons.

Hi Kiwi

Sorry I am not so technically knowledgeable but I will have a chat to our Skyline Guru this side and try and have this done.

I do currently have a catch can but pipes run from cam covers. Will have this done aswell.

Rods will be taken In on Monday to have the shot peen done.

I attached just some pic's of how the setup looked.

Thanks for all the valuable info from everyone so far it is appreciated?

[PLYNX]

Found em ! 

Here what can be done with a linisher, die grinder, sanding discs, etc etc.

Note the difference where excess metal is removed.

You'll also need a set of fairly accurate scales to weigh each rod to get them all the same weight towards the end of the process.

The finished rod is now ready for shot peening :

 

 

[Chev R]

11 hours ago, PLYNX said:

Found em ! 

Here what can be done with a linisher, die grinder, sanding discs, etc etc.

Note the difference where excess metal is removed.

You'll also need a set of fairly accurate scales to weigh each rod to get them all the same weight towards the end of the process.

The finished rod is now ready for shot peening :

 

 

Hey Plynx

You can actually see substantial difference's. Will have to get someone experienced to do this for me. Shot peening have confirmed with Fulrace collecting them today from my engine builder to drop off will find out if they can do it there maybe.

Thanks for all the hassle in showing me this

I have one more question if I may and this is with regard to the sump/oil pan and oil pick up? Here goes:

The series 2 sub assembly I bought did not have an oil pick up so I have been searching on whether I can just use my Rb 25 det oil pick up and sump/ oil pan.

I have come across some reading where guys say the Rb25 det sump needs to be modified and some fins cut but no real detail explanation.

Is there any one that may have more info on this mod and maybe pic's if available?

And is it necessary for me to have sump baffles fitted as this will be mostly a road car and from time to time on the track?

Thanks in advance everyone any responses will be appreciated