Rb20 To Rb22 Or Rb23?

[dxcorolla]

My rb20det shit a piston after getting tuned. Got another set of 20det pistons. mods are

t3/t3

40mm external

FMIC

injectors

exhasut everything to support big power.

Question is as i will have the bottom end in bits do rb25 crank and rods go straight in the rb20det with the 20det pistons?

I all so have spare 25 crank and rods here which i want to use. Has anyone done this before? Can anyone tell me if it actually works? From what i can gather it will make an rb22 or rb23?

Any help much appreciated.

Cheers,

Kingsley

[Mr. Oizo]

even if this does work, for the amount of money you'll spend, it wont be worth it

"everything to support big power."

but using a stock crank, rods and pistons..?

[dxcorolla]

Where is the extra money for what? I got the pistons crank everything bar new bearings. Which it will most likely get anyway while it’s in bits.

Did you answer my question? NO therefore I didn't need you opinion. Why run an rb20 for no extra money when it could be rb23?

I don't see the point spending $1800 on forged pistons for an rb20 to make a midget 350rwhp when stockers do just fine. I would also not go rb25! For the cost of buying a 25 I am building a 500hp rb30det.

How ever that’s not what I wanted to know. I wanted to know if any one could actually tell me if it works! Tomorrow is another day and since no one has told me I’ll be ripping them to bits and find out for myself!

[Mr. Oizo]

Labour...?

[neil_se]

You can't use the rb20 pistons in the rb23 anyway. If you searched you could have had all your answers an hour ago.

[dxcorolla]

I'd do the work myself. I have serached and the threads always turn into rb22 vs rb25 when rb25s are gay and rb30 owns it.

I have found rb25 crank and rods on rb20 pistons make rb21

cheers

[Roy]

Be interesting to see how you go using std 78mm pistons. I have thought about it as i have a spare RB25 crank/pistons and the RB20 currently in my car. The only problem is the psiton height of the piston, may make life difficult if using RB25 rods

[Drift Freak]

Hey guys, wierdly enough i read an article in fast fours not all that long ago, it was the september 2006 issue titled "Sinister Power For your RB". Straight up your ally dxcorolla. It goes into a little detail about what combinations ie crank, rods, and pistons to make RB21, RB22, RB23, RB24and even a RB25 but no real talk of machining issues. If you can't get a copy just give me a PM and I'll try to scan the pages and e-mail them to you. Good Luck i'll be following your journey closely as i'm a little worried about my bottom end too

[dxcorolla]

I would only do it if it made rb22 or higher but it needs bigger pistons to do so there fore I won't be doing it.

The rb20 bottom ends are fine, infact all rb bottom ends are good. get a good tune!!! It's all in the tune how long an engine will last.

Would be a good read if you could scan them pages 4 me. Probaly can't get the september issue i woudln't think.

cheers

[legend01]

you need at least 81mm pistons to make 2.2ltr with rb25det crank

Piston 81 mm crank 71.7 x 6= 2217cc

Roy rb20det standard pistons and rb25 crank =2056cc

[Roy]

Yeh, but look at the torque long stroke motors make, even if there is minimal increase in displeacement. You would only do itbecause it would be a laugh to build a motor out of left overs

[legend01]

well im building a leftovers then all the parts back in about 3 weeks at the machine shop now ,at long last

Roy here are some picks of RB26 rods and Rb20det rods from the measurement I have they appear to be same length to the bearting cap whereas from there they differ because the rb25 and 26 have bigger, big end bearings

Cheers Peter

[1kool34]

I'll scan those pages for you dxcorolla when i get home, legend01 is right the article mentiond using 4AGZE forged pistons that are 81.6mm i think, with a little machining to fit( but no serious detail:( ) I think a RB30 conversion would be the go for the costs associated.

[RB20/30Det_VL]

also the machining of semi circles in the block so the rods clear when the crank is on compression and exhaust strokes, 5mm deep from memory, with the 4agze pistons u have to machine the piston crown, which is a bit sketchy, they protude the block a little

pistons are the main let down cuz tomei 82mm are about $2000+ same goes with custom pistons that just leaves the 4agze

as legend01 said using the rb20det pistons only brings it to 2056cc by using the mathematical equation

hope this helps

cheers brad

[aphid]

i was under the impression that an rb26 crank and conrods were a direct fit into the rb20 and stroked it out to around 2400cc

[Husky33]

i was under the impression that an rb26 crank and conrods were a direct fit into the rb20 and stroked it out to around 2400cc

They are. But you can't use stock pistons, you need either rb24 pistons are 4agze pistons

[R31Nismoid]

And then you need to spend double that on the head to get it to actually flow something moderately decent... and then its more expensive than the RB25

Anyhow, the search button obviously wasnt consulted

http://www.skylinesaustralia.com/forums/in...*++RB23*++RB24*

http://www.skylinesaustralia.com/forums/in....2*++2.3*++2.4*

http://www.skylinesaustralia.com/forums/in...6&hl=stroke

http://www.skylinesaustralia.com/forums/in...3&hl=stroke

http://www.skylinesaustralia.com/forums/in...0&hl=stroke

http://www.skylinesaustralia.com/forums/in...c=90293&hl=

http://www.skylinesaustralia.com/forums/in...c=86271&hl=

And thats only half the threads as there are tooooooooo many to past.

So please use the search feature, it returns more useful information than this thread will probably get in it

Cheers - Ash