Alternative to OS Giken RB30 kit.

[proengines]

I'm just putting out the feelers to gauge interest in a setup similar to the OS Giken 3 litre conversion.

What the coversion will involve is an owner supplied RB26 block resleeved using a high burst pressure thick walled flanged sleeve pressed into the block and able to be finished anywhere between 86 and 88mm bore size. A CNC milled cast iron spacer plate will take the block height to the height of the sleeve and have an open deck to allow coolant to flow around the top of the sleeves. The spacer plate will have a viton o-ring style seal around the water and oil holes between the block and the plate. Any type of head gasket that can be used on an RB26 can still be used.

This will increase the block height to take an RB30 crankshaft and RB30 length conrod and a Wiseco piston. The idea of using the RB30 crank is to save the cost of an aftermarket crankshaft, you could use an aftermarket crankshaft but this would increase the cost significantly.

Conrods would be billet I or H-beam 6" using RB30 conrod bearings. We haven't decided on a conrod yet. We're also considering a 6.070" VG30 conrod using piston thrust location. The crankshaft, conrods and pistons would all be balanced along with the flywheel and balancer.

Head studs are ARP 12mm with 12pt nuts. Main studs are ARP as well.

The crankshaft will be fitted with screw in o/g plugs and an oil pump drive collar to suit the later pumps. a timing belt is also included.

The plan is to keep as many parts as possible "off the shelf" to make it more affordable.

The price for an assembled short engine would come in at less than half the OS Giken kit, somewhere between 10 and 11 grand. It still sounds a bit pricy but considering that there is no need to fit an adapter plate, modify the sump or oil system, all the mounts and accessories bolt straight in place on the block plus you have a slightly stronger block with more ribbing to start with, plus you still retain the piston oil squirters.

At the moment this is only in the early stages. I still need to dummy fit the parts in the block to check rod to bore and rod to cradle clearances etc.. I just want to see if there is much interest if we did do this?

[pnblight]

What would you think the hp rating of the kit could safety produce and rpm redline be.

As i have been told be some pretty knowledgable people the std gtr block is only good to around 750 to 800hp before may fail (this came from one of australias best gtr draggers)?

Would this limitation still apply or do you think with the additions of sleeves it may handle more?

pete

ps interesting idea tho and good to see some aussie willing to have a go

[nare]

yeah, thats a good question considering the OS Giken Kit can handle up to ~1400hp.

[Gav]

Agree with Pete - interesting concept

Would imagine that the RB30 crank may be the weak link at high revs?

[proengines]

I'm not 100% sure of the limits of the block. The OS Giken kit uses an N1 block and they have those running into the thousand and a bit hp. The regular 26 block is a bit more solid than a 30 block so it should last longer at the same power levels. The sleeves should add some extra strength and they are better quality material than the original block and are centrifugally cast.

The redline depends on a lot of things, a counterweighted crank will be able to rev reliably to higher revs than a non counterweighted one but saying that, the 26 crank isn't fully counterweighted. If money is no object you would go for a counterweighted crank. As for the reliability of the RB30 crank it is the same material as an RB26, the same hardness, similar design apart from the extra stroke and a slightly larger conrod journal. I'd be interested to run a fluid style damper and see what difference this makes to the harmonics.

What made me think of doing this is we recently machined up an RB30 for a conversion into a GTR, if you are paying by the hour for all the mods required it would come to a similar cost. I know that doesnt sound right but if you add up the mods to fit an adapter plate, mods to the sump and oil pickup system, air cond brackets, welding and redriling the rear bellhousing bolts on the sump, oil lines for an external feed to the pump, oil feed and returns for the turbos and all the other bits and pieces, plus the adapter plate to begin with it soon adds up.

I'm doing an engine for myself for an HR ute I have. It's a RB30 SOHC but what I might do is use an RB26 block I have here with these mods and see how it holds up. It will be a fairly high HP engine running 30ish psi with a HS50 or similar holset turbo and it will cop a hard time so any problems will show up fairly quickly. It will be a while before it's up and running. I'm just gathering bits and pieces at the moment. It's amazing what's around, in the last 2 days I picked up a dry sump pump for $152.50 and a ex nascar dry sump oil tank for under $100 delivered. It makes the japanese aftermarket pumps look a bit ordinary for the price.

I'd like to aim for the 700ish HP mark and then some nitrous on top. It should be fairly quick in a 1200kg car with a high stalled trimatic.

[pnblight]

yeah sounds good will be interested to read how it all goes (what you think its 12 month project or so)

Is interesting you bought up a thread like this as i had been concidering my opinions and i think it health for the skyline seen to talk about different options.

I know everyone has a hardon for the 3 litres but i see the best GTR in the world tend to be small cc and built to rev

Veilside run std cc, at i think around 1460hp 12500rpm (awesome)

GTR700 2.7June kit 1MW i think i last heard and has run up to 13000rpm on the dyno

I guess i was thinking about for the money 10 to 11 thou it would be hard to look pass a

std bore and stoke

N1 GT500 block $2870 or so N1 GT500 crank $3300 GT Rods $1320 (total $7500 +oil pump $1000)

good for what 1000hp to 1100hp

Or N1 GT500 block $2870 one of the 2.7 or 2.8 litre kits $9000 to $10000 mark

with this you know your got a combo good for what 1200hp to 1400hp out of the box

So i find it hard to concider making an unknown combo in that sort of price range when there are so many good combo out there to pick from.

But full current to the people willing to have a go

pete

ps is the KAKIMOTO Racing high block a spacer block with sleeves for $2000(sold by greenline)

[Sydneykid]

yeah sounds good will be interested to read how it all goes (what you think its 12 month project or so)

Is interesting you bought up a thread like this as i had been concidering my opinions and i think it health for the skyline seen to talk about different options.

I know everyone has a hardon for the 3 litres but i see the best GTR in the world tend to be small cc and built to rev

Veilside run std cc, at i think around 1460hp 12500rpm (awesome)

GTR700 2.7June kit 1MW  i think i last heard and has run up to 13000rpm on the dyno

I guess i was thinking about for the money 10 to 11 thou it would be hard to look pass a  

std bore and stoke

N1 GT500 block $2870 or so N1 GT500 crank $3300 GT Rods $1320 (total $7500 +oil pump $1000)

good for what 1000hp to 1100hp

Or N1 GT500 block $2870 one of the 2.7 or 2.8 litre kits $9000 to $10000 mark

with this you know your got a combo good for what 1200hp to 1400hp out of the box

 

So i find it hard to concider making an unknown combo in that sort of price range when there are so many good combo out there to pick from.

But full current to the people willing to have a go

pete

ps is the KAKIMOTO Racing high block a spacer block with sleeves for $2000(sold by greenline)

The problem with the short stroke 2.6, 2.7 or 2.8 litre RB's is the rod stroke ratio is far from optimal at 1.6 to 1. The RB30 has a much more desirable 1.8 to 1. This means less side load on the conrods, hence the big end bearings and the crankshaft itself. Less likely to break, last longer and make more torque at the same time.

The other issue is the top end mods required to handle the rpm necessary to make the power. This requires exotic (expensive to buy and maintain) titanium valves, retainers, collets, valve springs, hardened valve seats etc. This adds considerably to the cost. Most of which can be avoided with a 3 litre as it is simply not necessary to rev it so high to achieve the same power.

A further issue is gearing, if you are going to run 14,000 rpm then you need to carefully consider the gearbox and diff ratios. Running 4.1 to 1 (standard) diff ratios is not an option when optimising 1/4 times and TS's with that sort of power band.

As for power handling capacity, we have an RB31DET that made 930 bhp on the engine dyno. It had a std RB30 block & crank with forged rods and pistons and a worked RB26 top end. But there is no need to rev it past 9,500 rpm, so stainless valves are OK, normal spring steel valve springs, alloy retainers, standard collets etc. This is big saving over the exotics in intial purchase cost, plus they won't need servicing every 2,000 k's.

If the RB26N1 block increases this by ~1,000 rpm (not unlikely), that would endow the 3.1 litre with the same power capacity at 10,500 rpm as a 2.6 litre at 12,500 rpm.

You have to compare the cost of the whole package, as it is obvious that there is far more to it than simply comparing a 2.6/2.7/2.8 litre bottom end cost with a 3.0/3.1 litre bottom end cost.

PS, a billet crank girdle extending out to the sump mounts would increase the RB26 block rigidity considerably and thus remove some of the distortion loadings on the crank at even higher rpm's.

PS2; Hi Greg, nice to see that seed I sowed has grown.

[Dash]

Best way to market the kit would be to put it in an R32 GTR and run a number.

Might be hard to find people willing to part with that amount money on an unknown combination.

Great idea though ,as the only RB30's I know of that have run a ten or less in oz, have been OS giken packages.

[pnblight]

Doesn't Sub-zero (i think) do a rb30 package that runs some serious numbers (going off memory here from some mag acticles) so dont quote me.

from memory

rb30 bottom end

rb26 head

and just big single turbo

(the std ozzy 3litre sort of package)

anyone remember what they were getting out of the package?

[Dash]

That would be TRYO9s ,runs NOS, high stall trimatic,slicks in a 2wd

Wasn't saying they cant make power,as the Nizpro RB30/26 made over 1000hp.But in the 8 years or so since I first read about the conversion I havent heard of one running a good number in a GTR in oz.Could be wrong though!

[Amaru]

I just want to see if there is much interest if we did do this?

Hey Greg,

Id say if you could make a reliable high horsepower engine at a good price, alot of people would seriously consider it as an OSG alternative. Id also reccomend maybe posting this on the GTROC UK forums, as they seem to be nuts about OSG 3 litre kits, but dont like paying the price (they still pay however, as there really is no alternative).

If you wanted to set one up in a drag gtr, give me a call and im sure we can work out some sort of sponsorship deal in which you provide me with one of the above mentioned engines and a hollinger, and ill try and get it to run decent numbers

In all seriousness though, I might swing past and talk to you about this as im starting to save the $$ to drastically change my car (JUN 2.7lt). Current engine setup is great, but the big turbo and hp bug has bitten me

[Turbine]

I think it just boils down to the old horsepower per dollar saying.

It would be great to have 1000HP under your right foot, but how many of us really get that sort of power to the ground and have fun with it.

I reckon their would be more of an interest in a RB30 twin cam setup with a good 600BHP thats cheap enough for just about anyone.

Make thse kits available and you will have people jumping at them without a second thought.

That's my thoughts.

Turbine

[Amaru]

As for power handling capacity, we have an RB31DET that made 930 bhp on the engine dyno.  It had a std RB30 block & crank with forged rods and pistons and a  worked RB26 top end.  But there is no need to rev it past 9,500 rpm, so stainless valves are OK, normal spring steel valve springs, alloy retainers, standard collets etc.   This is big saving over the exotics in intial purchase cost, plus they won't need servicing every 2,000 k's.

On this subject, what max rpm is the RB30 crank capable of going to (with aftermarket rods)? Ive heard stories that they become "harmonically unbalanced" past 7000rpm, and others have said they can rev to 8500rpm without a problem.