What is needed to swap a RB into a 240sx? *FAQ*

Discuss the RB20, RB25 and RB26 series engines.
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Chaos the Xile
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soon2boost wrote:Im really considering doing the rb20 into my s13. Do i use the stock ka driveshaft or the rb?
you can use the stock KA but eventually will want to upgrade to a custom one-piece shaft.


TriniGT
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Just to add, for all RBs when changing the oil and water pumps, please while you're at it check to see what type of crank snout you have. RBs have an oil issue, for cranks with the shorter snout they will, at high RPMs, cause the oil pump gear to rupture because they do not fit flush in the gear. The fix for this is to get a JUN crank collar or something of the sort and have it machined onto the crank to have the crank fit the oil pump gear fully and hence no lsippage and a healthy engine. There are other oil issues because all oil is pumped to the head starving the sump of oil and spinning bearings, the fix for this is to install a small restrictor on the block on top of the other restrictor and block off the other passage. In the RB26 one of the restrictors is already blocked and the other will need reducing. To help oil flow quicker from the head to the sump you can remove the welsh plug from the back of the head and run a direct return to the sump. Please also try and get a baffled sump and oil cooler setup if you intend to do some drag runs and drifting.

skribblah
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do you have a picture of the shorter vs. longer snout? thakns for the tip..

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catatonicpinoy
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awesome info here^^ im looking into swapping out my sohc KA for an RB20det..

fanatic
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Just a question, I remember the RB26DETT used to have some issues fitting into a 240 because of the twin turbo setup, but that was awhile ago, so would I still have to convert to right-hand drive or is that no longer an issue?

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Joe
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you dont need to convert just need custom motor mounts and custom downpipes.

fanatic
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Ah, alright. Thanks. I'm actually planning to swap for an RB26 once I have enough money. Student budget.

unknownracer
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Car: 1990 nissan 240sx

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if i ask a question that has been answered, i'm new to this,i'm tring to put a rb25det into my 1990 240sx and i really need to find out as much as i need before i stick my foot in my mouth, you know what i mean, so if you have any pointers for me before i do this it would really help alot

unknownracer
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do you have to extend or will it match up?

thrashingdeath
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Mc Kinney told me that using the stock mounts and R32 crossmember lets the engine to high and up, is this true?

skylinegrl13
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everything you need to identify and fix here: http://forums.racebread.com/index.php?topic=1585.0

nissans13240sx
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the only way to mount a rb25 in a s13 is to use the r33 crossmember??

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DJButton
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No you can use the x-member and mounts or aftermarket mounts.

nissans13240sx
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DJButton wrote:No you can use the x-member and mounts or aftermarket mounts.
sweet thats what i thought. thanks

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1sikS13
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Car: 1992 S13 240sx

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RB20DETodd wrote:Another small thing i had to make a custom Throttle cable bracket, no biggie though,
any pictures of b racket if it works good for you would like to make mine similar when i go rb thanks

Shutup6794
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Car: Nissan 240SX

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Hey what up, i'm doing a RB26DETT swap in a 350z and i got a oil pan from a RB25 so i dont have to use the front diff cause the oil pan and diff is one peace and the flange for the oil pick up tube is in the way of the oil pan. Is there something i'm missing? Did i get the wrong pan? Please help!! thanks

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Coolwhip
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you gotta modify the baffling inside the oil pan to clear the pick up

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Death By Thrash Metal
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Hey guys this is a great section but: i looked around on mckinney and found they have a mounting kit (600) driveshaft 500, and rb25det tranny 1.3k. I also found that an rb26dett costs 3.4k on jdm racing motors. Now if i were to do it my self wouldnt this total up to be like under 6k?But of course you need exhaust and should upgrade to fmic single turbo mani, and fuel pump, oil pan? yikes... that adds quite a few k onto that original price!i mean just add the **** up. Also the mckinney mounts for rb26 supposedly make the swap as easy and straightforward (probably MOUNTING of the engine only tho) as swaping out original engines... how hard would this be i mean all the posts on rb26dett say its immensly hard but after considering most of them are more than 6mo old and b4 the time of the rb26 motor mounts, and twin turbo rb26 custom exhaust is it still really hard?It looks like i will actually get access to a decent shop (more than what i would have access to with pple inside who are knowlegeable.
Modified by Death By Thrash Metal at 10:43 PM 9/11/2007

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IWINULUZ
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in regards to the speedometer recalibration . That was a great instructional write up. but another option is from a company called ROSTA that makes speedometer recalibration piece.

just another option .
Modified by IWINULUZ at 1:13 AM 9/13/2007

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Coolwhip
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the Rb26 is not any harder than a Rb25. The thing thing is it requires more work. which in return requires more money.

As you calculated the price goes up pretty quick for a smooth swap. If you want to save $100 here and there you'll find out how hard it is really quick

Shutup6794
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Car: Nissan 240SX

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yea i know we did that are ready, the pan hits the flange of the oil pickup. It hits where the pickup bolts on to the motor.

redman
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If my price list is correct to swap a RB20DET on my 180sx ?

RB20DET engine pack : +-/ 1700 USD (delivered to france )OEM water pump : 149 USDOEM Oil Pump : 290 USDOEM Engine Gasket Kit : 255 USDMotor Mount : Top Hat - 350 USD (or R32 mount with crossmember ?? )Driveshaft : R32 or Top Hat / McKinney ???Exhaust manifold gasket : 40 USDElectrics Fans : ??R32 GTS-T gauge cluster : ??

Si vous parlez francais c'est TOP

THanks a lot


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Coolwhip
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Redman,

You won't need a new driveshaft for a RB20. The s13 will work. As well you won't need an extra exhuast manifold gasket since one already comes in the gasket kit.

You'll also want to price the following:

Timing beltTiming belt idler pulley and tensionerDownpipeIntercooler of some sort (if it dosent come with the motor)Clutch (while the motor is out)Fuel pump since the s13 wont hold up for the task.Spark plugs, belts, thermo, etc. tune up stuffHarness conversion and tech conversion (if you don't do it yourself)

Price those out and you'll be on the right track.

Good luck

redman
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Thanks a lot coolwhip , so my 180sx CA18 drivershaft is ok for the RB20 swap ? It's fantastic !!

nikko123
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Car: Skyline R32 GTS4

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YOU CAN USE AN [QUOTE=Kamin]I realized something today...I’ve been a moderator here for some time now and I’ve been telling people to search for answers to this question and never realized how scattered and sparse the information in. So in an effort to un-ufck that situation I figured it is time for a real thread

Please add information or correct me if I make a mistake! This will be a sticky and possibly an article if it pans out well!!

First things first: any supplemental questions related to the swap (i.e. wiring) can be found here zerothread/110509

What should I replace before the swap?This is a very hard question because everyone’s budget is different. Not everyone can afford to spend an extra $2000+ worth of parts before the engine is even in. What I recommend to replace is: 1) Water pump 2) Timing Belt AND tensioner/idler pullies 3) Oil Pump 4) Clutch (possibly flywheel if you have the cash flow) 5) All accessory belts ( zerothread?id=119087 ) 6) Fuel Filter 7) Fuel Pump (replace with higher flow unit) 8) Spark Plugs (more info comming soon)Those items will ensure you have a strong running engine for a long time. They are basic maintenance items that are overlooked by a lot of people who subsequently have engine failures.

RB20Will bolt in using stock mounts and R32 crossmember. you can also use aftermarket ones from companies such as McKinney and TopHat Will use stock 5 speed driveshaftCustom downpipe may be needed for both S13 and S14Electric fans are requiredCustom throttle cable bracket may be requiredTach adapter or gauge cluster swap required for accurate tach signal

RB25Requires electric fansCustom throttle cable bracket may be requiredTach adapter or gauge cluster swap required for accurate tach signal. Then this one gets a little more complicated. MountsR33 crossmember and mounts can be used, BUT you must cut the hood skeleton or replace the factory 25 manifold with something like a Greddy unit or similar. Mckinney and TopHat make mounts if you only have a motorset and no crossmember.

DriveshaftThe cheapest route for this is to open the phone book and start calling offroad shops and driveshaft shops. You will generally spend $225-$275 for a custom shaft if you bring them the parts. They will tell you where to measure and then make the shaft.

Shops like Mckinney do make a bolt in 1 piece shaft provided you are using their mounts but they are rather expensive.

DownpipeIn a s13 the stock downpipe clears if you have mounted via the crossmember swap or aftermarket mounts.

In a S14, it’s a bit different. Using the R33 crossmember you will probably need a custom downpipe. If you use aftermarket mounts the stock R33 downpipe will work (may vary by mounts, generally it will work no problem).

RB26First, if you are considering going with a RB26, I hope you have large sums of money at your disposal. This is a very very expensive swap. Expect to spend in the 8,000-$10,000 neighborhood to do it right. This guide is going off the assumption you will be using the stock twin turbos. Things change if you convert to single. First things first, you cant use the RB26 AWD transmission without some modification to the floor of the 240sx. There are RUMORS of it fitting without modification and AWD components working but we do not have verification yet. So ffor this guide I assume you are using a RB25 transmission.

Electric fans are requiredTach adapter or gauge cluster swap required for accurate tach signalCustom throttle cable bracket may be required

MountsNo option here, you need to go aftermarket. Mckinney.

Driveshaft Same as the RB25’s requirements.

Downpipes Again, no option here. Need McKinney downpipes.

If I have missed anything or you guys want me to add something, just post it up! Thanks NICO!

U can use an SR20det 3" Down pipe with the RB20det motor swap... I can get the cheap...

nikko123
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You have to get the cluster from a skyline bro. The tach wont calibrate. Also with using the crossmember you have to carve away some of the hood bracing... and the tranny sits about an inch or toward the front... Get the mounts...

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eh?
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The S14 tach can be calibrated to read reasonably accurate. Most factory tachs are off by a certain amount so it's a moot point.

abubika345
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Car: 90 hatchback sr20

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Im looking at doing the rb20 or rb25 conversion (depending on money) and i have a 90 hatch....what all do i need to do if i want to keep power steering since the pumps on the opposite side on mine rather than the other side on DOHCs

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DJButton
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Get a DOHC PS rack or at least the lines from one to route the connections to the other side.
nikko123 wrote:You have to get the cluster from a skyline bro. The tach wont calibrate.
Mine works quite well thanks. The only ones you can't calibrate are SOHC tach's anything DOHC will work once calibrated and usually will be good to around 300rpms or so, often closer.

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Young_240_Guht
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I've heard that the RB transmission and the KA are the same... But i dont know if they were talking reliability or bolt pattern and stuff. Could you bolt the KA to the RB20? Probably a stupid question.

And you need the RB20 ECU and harness?


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