RB24 Stroker

[blackrb20silvia]

hey ppl

just a few questions for you guys

1..parts needed??

gtr rods and crank, 82 mill pistons...what else?

2..what head gasket is usedand about how much?

3..i know of TOMEI pistons where do i gety them and how much?

3..what size are the standard pistons in rb20 silver top? (i need to know the diff between the 82 mm and the standard ones cuz my bores are pitted from water need to know if i will clear it with a bore?

4..is there anything i need to know bout the build like problems or mods i need to do or whatever

5..is there already a guide on the net for the 24 stroker alreadt if not there needs to be one

any info i can get on this stroker kit will be great i want to get started straight away!!!

please??please??please??please??

matt

[Wazz]

www.nengen.com has your tomei pistons... 82mm pistons i believe

[browny]

1..parts needed??

gtr rods and crank, 82 mill pistons...what else?

Also think about new oil and water pumps, gaskets, fasteners etc.

2..what head gasket is usedand about how much?

Maybe have a custom copper gasket made up. Shouldn't be too hard to find an Aus company that will do this. Probably cheaper than the imported jap stuff too.

3..i know of TOMEI pistons where do i gety them and how much?

As per Wazz's post. Expensive tho, when I last looked around $2k.

3..what size are the standard pistons in rb20 silver top? (i need to know the diff between the 82 mm and the standard ones cuz my bores are pitted from water need to know if i will clear it with a bore?

78mm bore std

4..is there anything i need to know bout the build like problems or mods i need to do or whatever

It's not such a common build in Aus because you can get comparable or better results by other cheaper means (ie just put an RB25 in). Hence no-one can really tell you what all the issues are going to be and it's largely going to be a case of 'suck it and see'.

To fit the Rb26 crank and rods you need to relieve the block.

You will also need to modify the head to suit the larger bore.

4AGZE 81mm pistons have been brought up a couple of times as a cheap alternative to the Tomei stuff (eg ~$100 each), however i've never seen any information about where the piston ends up in the bore (height wise). The RB26 rods will need to be bushed if used with these pistons.

If I can get the length of a std RB20 conrod then we'll be able to work out where the piston will end up in the bore and decide whether the 4AGZE pistons are worth pursuing

5..is there already a guide on the net for the 24 stroker alreadt if not there needs to be one

Not that I know of. There are a few threads on here that cover most of this build tho.

[FATGTS-R]

Do a search on "RB24" as its been mentioned a few times. But in short I beleive the 4agze pistons need the pin height altered to suit. But they are forged and ceramic coated.

I got a back issue of HPI mag with something I bought and they were carrying out the conversion. Someone may have all the issue numbers and can give some more info.

From memory, they used 82mm pistons but had to sleeve the block as the wall thicknesses were too thin in some areas after a sonic test.

[R32 4 Door]

Yes, HPI started doing this coversion in issue NO.44. The Main parts they were using were:

RB26 Crank & Rods

RB26 444cc Injectors

Tomei RB24 82mm Pistons

Tomei 1.2mm Metal Head Gasket (They say 7.9:1 Comp. 83.5mm Bore Size)

Tomei Poncams with 8.8mm of lift (Allowing to keep hydrolic lifters) 264 IN 272 EX

Tomei Valve Springs

OS Giken Adjustable Cam Gears

ARP Rod Bolts

The turbo they were using was a old externally gated Trust kit made in the early 90's by IHI (RHC6-19C) which required a flange to mount to the exhaust manifold. It is a low mount set-up which is quite a bit bigger than the standard RB20 Hitachi turbo.

In a later issue they reported that the RB20 they had bought was basically shagged and could not be used for the project. They then bought a R32 Sedan. This will be the engine that they will be using but they still have not started.

I was thinking of doing this myself when I saw it, but you add up the costs, It would be around the same money or maybe cheaper to do an RB25/30 Conversion instead (Labour costs would be pretty high compared to a 3.0L conversion). In the end it comes down to if you want 2.4L or 3.0L?

Looking forward nonetheless to see what figures this motor produces if they ever get round to building it.

Hope that helps a bit,

Chris.

[blackrb20silvia]

yeah guys thanks

i just need a few i deas as to what i can do with a spare block and head i have here

block needs to be bored out to be of any use other wise all its good for is a boat anchor

and i dont have a boat

any suggestions it seems like a waste just to throw it away????

[blackrb20silvia]

any suggestions? i want to do something with it dont care how much it costs ill do it over a few months

???

[Angry]

i dont think machining costs will be thatttttttt great ... saving your money purchasing stuff for the right price is what it is about

i have my gtr crank, rods, cams, injectors, fuel rail, nismo reg, rb20long motor, vg30 turbo (to be hiflowed.steel wheeled).. so far thats set me back just under 2000 all up.

pistons will set me back around 680bucks for 2 sets of 4agze off the shelf pistons. offset bushes for the conrod ends are an inexpensive and proven practice. Set of rings wont set me back an arm and a leg.ARP Vg30 rod bolts are fairly cheap. metal head gasket from tomei 80.5 should be right.. but i'll double check .....as the 4agze pistsons are 80.5mm themselves.. far as i know.. not the previously remarked 81... **** all difference.. but anyways..

Machining would probably be around the 1500-2000 dollar mark ...MAX i would like to think.

hopefully my m8 that built my last racemotor will help me out with the assembly.. but i'm comfortable if i had to do it myself. if u know someone ..and have everything ready to be put together ..giving them a few slabs and 500bucks or something should be plenty to have a complete motor in a month or so ..lol

Just my thoughts anyways

Matt

[browny]

Matt

Have you worked out how high the 4AGZE pistons will sit in the bore, using the std RB26 rod length and piston pin placement?

This is the only thing I haven't been able to find out.

[Angry]

i havent as yet.

if anything they will sit too low on the piston..... i think.....but thats a guess as i dont have my pistons either for the time being.

i'm intending to use 4agze gudgeon pins with offsetted bushes to suit the gudgeon placement to the rb26 rod... if that makes sense. i think the piston has to be raised so it clears the oil squirter on the top of the rod.... similar to what they explained in the Rb24 build in HPi.

i think SK has the bits and piece..and the info i know regarding the rb24 is from him.

maybe he'll be able to answer your question more correctly in terms of height.

thanks

Matt

[Sydneykid]

Matt

Have you worked out how high the 4AGZE pistons will sit in the bore, using the std RB26 rod length and piston pin placement?

This is the only thing I haven't been able to find out.

It depends on the compression ratio you want, how big the combustion chambers are when their volume is equalised, the gudgeon pin height (offset bush) and the head gasket thickness.

If you use a non offset (gudgeon pin) bush, 0.8mm head gasket, 52 cc combustion chambers and want an 8.5 to 1 compression ratio, then you take 1 mm of the block deck height. It's no big deal and not something you can work out in advance, you have to measure it all up before you deck the block. And remember EVERY engine is different.

PS don't rely on the combustion chamber volume yet, I remember it as 52 cc's but I will check my book and come back and ammend this post if it is different.

[browny]

ok, all I am really wanting to do is get a ballpark on where the piston ends up. Everyone always says 'you can use 4AGZE pistons' but then no-one can say with any confidence where the crown is going to end up in the bore. Taking a mm or so off the deck height isn't a problem but ending up with the crown poking out of the block by an inch certainly is!