Jump to content
SAU Community

Recommended Posts

Hey Guys

In the stages or tearing my engine down, ready for a rebuild.

There are a few retailes of RB30 Rods at the moment

- SPOOL

- ARGO

- Rod Factory

But whats got me confused is

Centre to Centre: some have 152.5mm and some have 155.5mm

Will either of the 2 work?

Anyone else come across this and what have you done

JD

Link to comment
https://www.sau.com.au/forums/topic/190554-rb30-rods-height-make-a-difference/
Share on other sites

Brad I spoke to you this morning about that, thanks for your help

Rods Factory, i know they are on ebay are 155.5mm

RacingPartsfactory.com also have them as 155.5mm

Will using the 155.5mm Rods pose a problem? I know they are 3mm longer, i am planning on using CP 8.2 Flat top Pistons with them

Edited by D1AUS

Umm yes - the pistom will protrude 3mm out of the bore and you wont be able to bolt the head on.

It just wont work - you will need to get a custom piston made to suit.

Brad I spoke to you this morning about that, thanks for your help

Rods Factory, i know they are on ebay are 155.5mm

RacingPartsfactory.com also have them as 155.5mm

Will using the 155.5mm Rods pose a problem? I know they are 3mm longer, i am planning on using CP 8.2 Flat top Pistons with them

But from my calculations, it is ok.

RB30 Specs

RB30 Deck Height - 9.075" (230.5mm)

Stroke - 85mm

Crank Throw - 42.5mm

Compression Height - 1.280" (32.5mm)

Using Spool/Argo Rods - 152.5 C/C

Deck Clearance = 230.5 - 42.5 - 152.5 - 32.5 = 3mm

Using RacingPartsFactory/Rod Factory Rods - 155.5 C/C

Deck Clearance = 230.5 - 42.5 - 155.5 - 32.5 = 0mm

Is that right by your calculations, therefore using either Rod, should not matter.

However, if you see an issue of deck clearance, you can always use RB25/26 pistons instead, as they have the same bore, but a smalled Compression Height

post-43743-1193213677_thumb.jpg

Edited by D1AUS

So that calculation above is wrong then??????????????????????

RB30 Compression Height - 1.280" (32.5mm)

RB26 Compression Height - 1.193" (30.3mm)

RB25 Compresson Height - 1.240" (31.5mm)

Using 152.5mm will yield 3mm Deck Clearance via that calculation

Using 155.5mm will yield 0mm Deck Clearnace via that calculation

Now thats even more confusing

Why not just use the Argo or Spool rods and be done with it? They both work without any issues?

Its not just a matter of simply using any rod. I'm trying to maximise the compression ratio etc with my setup. And with the calculations above and speaking to Distributor for CP in QLD.

Standard Rods have a 3mm deck height according to this calculation. As the CP RB30 Pistons are Dished not domed. Thats my arguement here.

Just trying to find out from others who have done this etc.

I understand Spool Rods are of good quality, but just seeing the available options to maximise the setup, thats all.

JD

Im building a 30/26 now with 9:1 comp using argo rods 152.4mm center to center

also using je custom piston compression ,height of 1.283,

0 deck height

havnt got the pistons yet but thats what i did to get the comp i want

Im building a 30/26 now with 9:1 comp using argo rods 152.4mm center to center

also using je custom piston compression ,height of 1.283,

0 deck height

havnt got the pistons yet but thats what i did to get the comp i want

Thanks for the feedback mate, I assume they are a domed piston????????

Im not trying to sell you my rods - just trying to explain that you are going to get in all sorts of shit of you use those ones with the 155.5 c/c

CP 8.2:1 are a flat top that come flush with the deck.

CP 9:0.1 are a domed piston. The flat of the piston come flush to the deck with a small dome in the centre.

CP RB30ET pistons have a small dish with valve reliefs.

To get 8.5:1 your prob best to use the 8.2:1 and skim the head - but obviously work backwards and cc everything first to calculate how much to take off the head.

Im not trying to sell you my rods - just trying to explain that you are going to get in all sorts of shit of you use those ones with the 155.5 c/c

CP 8.2:1 are a flat top that come flush with the deck.

CP 9:0.1 are a domed piston. The flat of the piston come flush to the deck with a small dome in the centre.

CP RB30ET pistons have a small dish with valve reliefs.

To get 8.5:1 your prob best to use the 8.2:1 and skim the head - but obviously work backwards and cc everything first to calculate how much to take off the head.

Brad

By all means i do appreciate all your help, thanks very much

I'm just going by all the figures at the moment. Obviously, I will dummy everything up check chamber cc etc.

Just by the specs, thats what i get from the calculation. I know standard rod is 152.5mm

From your experience, what is the standard deck clearance for RB30? standard parts

deck height is 0 rod length should be 6"{152.5m} dont use any other rod length

and yes my piston will be dome

if u use the cp piston u can buy the right one off the shelf for 8.5:1 comp

u will only achive this if ur block height is standard and combustion chamber cc's are close to standard{65cc"s from memory}

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

    • I've heard the Tomei USA head gaskets are decent if you want to o-ring the heads but otherwise not recommended.
    • The 296mm rotors are the R33 turbo brakes. The 310mm rotors are the R34 turbo brakes. The calipers are nearly the same, but not. They're the same caliper but the R34 caliper has longer legs so that it sits out far enough to go over the rotor. The pads are the same for both. When you say, "I bough tsome EBC"....did you just mean pads? Or rotors? 310mm rotors fit under 17" wheels. There may be some wheels without enough clearance though. I can't fit my fingers between the barrel of my wheel and the "corners" of my R34 calipers, but there is plenty of room behind the spokes. This is on Enkei RPF1. You can fit 324mm rotors inside a 17" wheel, but I'd be willing to bet that it would be close to impossible with the Nissan/Sumitomo caliper (using an adapter, of course), because the Sumitomo caliper is fatter than the Brembo caliper that is supposed to go on the 324mm rotors.
    • Hi. Can someone tell me what brakes(and mainly WHERE) can i buy brakes on R34 GTT? I bought some EBC which SHOULD go on my car(i have GT but it has GTT brakes) but it does not fit, Brakes are "too" small(296mm) Are 310mm be good or? I have 17 inch wheel so no "big boys" but for me driving i just need one that fits and i can get here in EU/Czech.
    • Since winter isn't that harsh anymore in Poland, i will definetely drive it 365 days a year 😉. But if the snow hits i will try it for sure and let U know. Only swap i am planning to do is of course R34 GTR front 😍.
    • Hey. Very valuable information about pitwork, I will pay attention when buying any consumable parts 🙏 As for the carpets - I got a handful of information from nengun, from which it appears that indeed the carpets for the driver's side are OEM. They are not able to show me any pictures due to the long chain of different sales entities but after I place the order, as soon as the goods arrive at the nengun warehouse from which they will send the shipment to me they can send me photos and if my purchase differs from OEM I can immediately return it / cancel the purchase. I think I will give it a try 😉. Of course i'll let you know what's what as soon as i get them P.s. I know the topic is not relevant to the thread, but both nengun and amayama have these SICK 😍 trunk room lamps available. Do you know anyone who ordered them? I need to have one in my car
×
×
  • Create New...