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swap time!


Guest zline

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alright -- here's the deal

 

got a 70 240Z here's what i plan on doing:

rb25det swap

 

I read stoneys "guide" but it was for an RB26 = I was wondering if the oilpan mods needed to be done to the RB25 also or if i can jsut use a Z31T oilpan? also - I read he used a fairlady Z RB20 motor mount...where can I find these stateside? (I dont think courtesy nissan carries these mounts =)

 

Also, how much modification is required to :

1. transmission cross memeber (is it just cut & weld?

2. what transmission mounts do i use? do the RB25 mounts bolt to the Z?

3. Radiator & intercooler fitment between frame rails

 

TIA

 

Daniel aka. ZLine (Z+Skyline)

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Daniel,

Welcome.

First, their is a RB25 oil pan that is a rear-sump pan. I don't know the specific application, but I have one in my garage. If you are super interested, I can do some research and find out what it came from. I think the GT-S RWD car.

So some RB-25's have front sump, some mid, some rear. I think most are rear sump pans. You can always ask the importer you are buying from. If it is rear sump, you are fine and no mods should be required.

As for the engine mounts, two things. First, they mount the engine rather far forward. If you are familiar with the V8 swaps, there is the Scarab position and the JTR position. The JTR is the prefered, as the engine is set back and down. The mounts Stoney used are similar to the Scarab position. Brad and I are using custom made mounts that set the RB26 as far down and aft as you can put it. If you are not road racing, it really won't matter much, so I suggest going with the ready-made mounts. The part numbers are listed in the forums on the 240z.org website. Look here:

240z.org modified z forum post

Next, as for what modification is required on the tranny x-memeber? It depends on what trans. you use. The RB-20 trans is slender and nearly the same size as the stock 5 speed ZX box,(81-83). The RB-25 GT-S box is big and bulky and will require cutting the "ears" in the transmission tunnel off and a custom mount bolted to the bottom floorpan,(such as a JTR mount).

With some research, you will find you can likely bolt it all in with the right selection of parts,(maybe some minor mods).

The radiator will have to be an aftermarket one. You can order a camaro radiator from JTR and it will work in the Z. You other options are Griffin or Ron Davis Racing. It is about $300-350 for a Griffen and $400 for a Ron Davis, both full custom aluminum. Look at the RB motors to see what side the coolant pipes go in and out from,(i.e. same side, opp. sides, etc.. the Z is opposite sides).

And the intercooler is a full custom job. But take a look in the turbo section and ask about intercoolers as lots and lots of people have put various intercoolers on their Z's for many different motors.

-Bob

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Thx for the welcome and informative reply Bob

 

well in a matter of fact i do intend on road racing!! that means the RB20 Z mounts are out...the clips are all rear sump -- if they all happen to disappear i know 2 or 3 importers that can get me the engine rear sump for the same price.

 

Cuong said he was going to be making mounts etc., so I think I sould just wait for him to start doing that as 1. the quality of his swap is top notch 2. he said he'd be fabricating the parts after his own swap; I think that'd lead to very high quality parts.

 

Intercooler wise I decided to run a trust two core intercooler and just do custom piping b_hand.gif to fitment issues!!

 

I'd really like to use the RB25 trans as 1. it comes w/ my front cut 2. I think it can take more power and the rear gear is better suited for my application.

 

Anyone have any mounts that make this a Mid engine Rear drive swap hehehe ^_^

 

TIA

 

Daniel

 

Personally I always use BeCool for aftermarket radiators -- but since you suggest a

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Guest michael_240Z

if you're still wondering what app the rear sump RB25DET is from, it's from an R33 Skyline GTS 2.5t. it is RWD only. it is the slightly tamer, less powerful, non AWD version of the GTR.

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for the oil sump you can use the oil sump out of an 200zr, (it fits my RB25DET) the part number is:

11110 - Oil sump

15050 - Oil pickup

15200G - Oil pickup O Ring

11232 - RH Mount

11233 - LH Mount

11220 - Rubber mounting (LH and RH)

Don't think any skylines had a rear bias sump

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hey 250zt thanks for the part numbers...does that set the engine down and back or is it "offcenter" so to speak?

 

I need the lowest and farthest back as possible.

 

also, how was your fitment with the crossover intercooler piping?

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Hey even though it was for an rb26 the rb25 is pretty much the same. in fact there are no oil pan or pickup mods, its all bolt on. you just get the pan and pickup for the 200zr and thats it.

 

If you going to race it i would go with the r-33 gts-t 5 speed its stronger. rockon.gif

 

tranny mount will be custom.

 

the best way to do the intercooler is to get the piping mad so it goes thru the holes in teh core support.

arizona z car makes a good all aluminum radiator.

 

there are no skylines with a rear sump they are all front sump. twak.gif the z31 rb20 is teh only rear sump rb motor.

 

My engine position is alittle forward but it is basically in the same spot as the L series motor in relation to the firewall. the only thing i would change is how hi it sits. then again if it goes any lower the oil pan will be below the a-frame.

 

stony

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I just used the Z trans mount replacing the R33 trans mount (bolts right on) and used the existing gearbox car mounts, made my own engine mounts as the engine needs to be lower then normal as I have a gto kit on it. I'm going to get a new drive shaft made up and get them to do the IC piping, exhaust, wiring up to the dash, etc at the same time. (not finished yet) don't know how far down the 200zr mounts puts the engine but from what I have read it is a bit higher than is needed. yes no mods needed for the 200zr oil sump + pickup for the RB25 and RB20 blocks

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Hey all...thanks for all the replies.

 

I've decided to use 200ZR engine mounts and fabricate a 321 SS trans mount.

 

I dont want to have to modify oil galleys or anything so i'll just use the 200ZR sump & pickup.

 

for the mods i just plan to run 2x r34 gt-r pumps 610cc injectors sds ecu boost controller fmic & top mount style exhaust manifold

 

since i'll have the fuel and cooling system in place i'll upgrade the turbo to a GT2835R unit down the line

 

With the top style mount exhaust manifold it should simplify clearancing & intercooler piping issues.

 

I dont want a snake pit

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Stony! thank you for taking a peek at my thread! as you have been through this swap w/ albiet a different motor I greatly appreciate your input.

 

What engine mounts did you use? 200ZR?

 

I'm going to use the R33 trans no doubt as it will see high road racing applications..while the tranny is out i will low friction coat the gears & cyro treat them for added strength.

 

As I said, I need the lowest and farthest back position I can get.

 

Stony...what did you do for the driveshaft? Shorten & use HD ujoints? tahts what I plan on...or getting Dennys Driveshaft to make one of their 2000hp capable ones.

 

I really would like to do this swap as 1. it provides me with best power capability and most modern technology nissan provides save the VQ/VH series engines. 2. Zline sounds cool? nah but on a more serious note..I believe for my application which is drift and roadrace...the rb powere'd z car will be very good.

 

Stony, how would you rate your car all around...drivability handling speed & what are you doing for brakes?

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  • 5 months later...

Hi All,

 

good to see you are starting another RB Zed project Daniel. Let us know how you get on.

 

Sorry to all, but I have no intention to go ahead and produce the engine mounts or any other parts needed for an RB conversion. I was going to. Had a spare RB26DETT block with a two holes in the sides from a conrod and was going to use that to jig up some sump. However due to lack of time etc I will NO LONGER go ahead and produce these. (I barely have time to look at my own RB26DETT 240Z! :( )

 

I think Brad D and skyline240z make engine mounts for sale. Brad D may also be selling sumps???

 

Cuong Nguyen

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Guest zline

Hey

 

This post is still around? wow...pretty old, *sniff* brings memories back. I sold the car, due to ahh problems - not with the car no, not at all - I got it all to go smoothly and it was all quite simple actually I just had a buddy of mine wire it up and I did the install and tuning and fabrication of pretty much everything save the oil pan which a local speed shop did.

 

The RB-Z while viable, and very cool - in the US doesn't make sense to me when the V8Z:

 

1. costs less

2. a lot better documented even though I have personal knowledge of the steps required to successfully complete this swap, the V8Z has just been done more in the states and will be a lot simpler for those who do NOT to complete

3. with the same or less in parts - the V8Z will do the same thing that the RB Z can, make gobs of power and either go straight really fast or handle really fast;) I prefer the latter.

 

My sig still applies if you need someone to source a part for you from japan shoot me a PM and I'll do it, but if i decide to get a Z again, it'll be with a mild (400hp/420ftlb) small block.

 

Gotta love that good old american iron.

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  • 2 weeks later...
Guest Anonymous

How much does a 400 HP small block set up run for. The whole SWAP, i.e. aftermarket fuel management, mounts, rad, etc. I mean you can pick up a RB25DET from Venus Auto for 1500 bucks, or a 1jz supra engine + tranny for nearly the same price. Do a basic rebuild on it if necessary (nothing fancy). If you're handy with a welder and fabrication, you're laughin.

 

Nothing wrong with V8's, they are pretty "thrilling" to ride in the first few times. I mean a buddy of mine is running a supercharged firebird non intercooled with roughly 450 HP. Its fricken noisy and not a smooth ride.

 

The RB or JZ engines seem classier to me, finesse rather than brute force.

Sort of like a super car rather than a muscle car. Just one mans opinion but I'd take an inline 6 with twin turbos and a six speed tranny over any V8.

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