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hey guys

been doing lots of reading and searching through archived threads and also talking to friends in japan also...

my old rb20 i decided to take the head off to really look at what damage was done by the transport company... piston 4 rings are totally gone and some nice scores in that piston... apart from that everythingelse is dirty but looks to be ok (especially cyl bores)

looking to do an rb24 conversion using 26 crank and rods... before i send it anyway i do want to shop around and get most parts myself to make it easier for my builder and cheaper for me

rb20 complete engine - check (still turns over... on 5 cyl :wave: )

n1 oil pump

n1 water pump (both of which fit correct?)

when looking at crank and rods what are the differences between 32/33? i have a friend who has 33 crank and rods in really good nick with no fractures... and i understand the gtr 33 crank has benefits inregards to the oil pump drive?

and the 2 big questions... pistons (4agze forgies will suffice? i have looked into the tomei .82 rb24 pistons which are a bit under 2k delivered from JP) and headgasket? what to use? could not find the tomei rb24 headgasket on the site... custom?

also any other recommended bits while im at it? i want to do this once and do it properly... working 56hour weeks is hurting also just to pay for it!

this motor will be running a td06-20g 8cm ext gated setup with ap eng rb20 power fc (already have this)

any help is much appreciated guys... its been a while since ive fiddled with internals (takes me back to motor school)

thanks!

Edited by Hella Flush
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have you looked at the rb30det project? will probably cost less and youll get more displacement. also no need for n1 water pump, it flows less at lower rpm compared with the stocker, its only useful for track cars

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track only build up here no rego... thus from my understanding the flow efficiency at higher rpm was better?

ive tossed up the rb30 and even 25 to 26 idea... even a 26 itself... im happy with rb24... its a loyalty i have to the engine... and externally nothing will have to change

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i dont know why... mates saying 25 25 25... and do a 26 stroker... as we have a spare 25 at his place... but for some reason i just want to stick with the 20... the heads are nowhere near as efficient and with alot of head work you can get close (id say on est around 75% to the flow of a 25/26 head) but still something about them... they were the original RB... they have a long history and have certainly satisfied/assisted alot of the great track drivers we know today (both drift/drag)

rb20 block FTW!

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I hear ya there is also the RPM issue compaired to the 20/25 or even the 30 I know someone who has a rb30et in a R31 and he said doesnt come close to the rb20det he is even selling the engine and putting a 20 in instead.

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As some of the guys have already posted, an RB30DET is truly a better proposition. I have almost all of the parts necessary to do an RB24, have had for a number of years. But when I add it up the RB30DET costs less (build and run) and has far greater attraction (now and potential later on).

My RB31DET (3.1 litre) produces the same power at 7,500 rpm as an RB24 does at 9,750 rpm. I don’t need high duration cams or solid lifter conversions or mega valve springs for 9,750 rpm, for 7,500 rpm I really don’t need much at all. Standard water pump is fine, no change to the diff ratio required, I don’t need to gear down the alternator or the power steering pump. With much milder cams and 30% more capacity I don’t need to rev the beegeesus out of it to go fast. I don’t need to launch it at 7,500 rpm to avoid the bog down, so the clutch lasts a heap longer.

Having done it many times, I can assure you when you add it all up, the RB30ET is a much more logical route to take.

:D cheers ;)

PS, take a look at the HPI R32GTST 4 door for sale, it has an RB24 in it.

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I agree with you hella , The old rb20det have been a good engine and there are other options and many arguments about fitting bigger engine's BUT how many realy quick rb20's are out there in Australia.There's plenty in japan but jack shiet out here I have an rb25 sitting in the shed and everything to build a quick one including the forged 40thou oversized pistons and rods one day i'll get to it .but I aim to get my new car running better than the old R32 I had and it was running big hp numbers on a stock bottom end and some pretty good times down the quater mile at wsid to and would have gotten better. My aim is to get an rb20det powered R32 down the quater in an 11 sec run and i got close with the old car .Im with silv and roy go the rb20

cheers Peter

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LOL...any "what to do to my RB20 thread" always turns into a "do an RB30" :)

I think SAU often tends to talk down how much things cost. A few smart mods to an RB20 will make a for a quick and fun car. I for one find it more fun to spend say $2000 on mods and $3000 taking it to the track and flogging it. Better then 5k on the engine and not having any money to enjoy it :)

If you can afford to do both then i want your job :devil:

Also, on the stroker thing. What is the pin height on an RB20 piston comapred to RB26 and RB25?

It would be very cheap to grab RB25 or 26 crank, match it up with RB25 or RB26 rods and use them with the std RB20 pistons. It would be very cheap, give you more stroke and torque, without as much machining and expensive pistons and mods to head. Im thinking about doing somehting silimar with my spare RB20 :spank:

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LOL...any "what to do to my RB20 thread" always turns into a "do an RB30" :devil:

I think SAU often tends to talk down how much things cost. A few smart mods to an RB20 will make a for a quick and fun car. I for one find it more fun to spend say $2000 on mods and $3000 taking it to the track and flogging it. Better then 5k on the engine and not having any money to enjoy it :spank:

If you can afford to do both then i want your job :)

Also, on the stroker thing. What is the pin height on an RB20 piston comapred to RB26 and RB25?

It would be very cheap to grab RB25 or 26 crank, match it up with RB25 or RB26 rods and use them with the std RB20 pistons. It would be very cheap, give you more stroke and torque, without as much machining and expensive pistons and mods to head. Im thinking about doing somehting silimar with my spare RB20 :)

I thought of doing that, but at 2,060 cc's with an RB25 crank and 2,120 cc's with an RB26 crank is it really worth the effort? Last time I looked, 4AGZE pistons where pretty damn cheap.

:) cheers :)

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I thought of doing that, but at 2,060 cc's with an RB25 crank and 2,120 cc's with an RB26 crank is it really worth the effort? Last time I looked, 4AGZE pistons where pretty damn cheap.

:) cheers :)

But the pistons, though cheap still csot what. $400-600? Plus the machining and gudgeon pin mods, mods to the combistion chamber etc etc.

It may only be a few extra cc but the stroke could bump up the torque a little everywhere. You would think the stroke increase would do more then any displacement increase from boring the engine.

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