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RB Motor with Triple carbs, Can it be done? Z432 Z432-R


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#21 benny

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Posted 22 April 2010 - 05:42 PM

how thick are the tops of the rb covers, could you cnc 1-2mm off the top to extrude the same design??

Ben

#22 Hunter

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Posted 22 April 2010 - 06:03 PM

The two side cam covers are about 4mm thick max. and the center cover is made of plastic. good idea but probably wont work.
If it was to work you would have to make a new center cover and add some meat onto the cam covers, with a piece that comes out over the timing belt cover, and cut the original timing cover top off.

I was thinking. Cut the top off the front timing cover, weld some tabs on the side cam covers, take the center cover out, and make a replica cover to bolt over the top.
It would not be perfect but as long as it was a reasonable faxcimilie I would be happy.

#23 NZeder

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Posted 22 April 2010 - 06:27 PM

Ok thought I would share an old link I had saved. Not a S30 but a S130 fitted with a RB31D running 50mm Mikuni carbs ;)
Posted Image
Link to the whole page = http://www.testaross.../s130/index.htm

Re the cam covers - I think the RB26 centre is not plastic as I have seen polished covers ie alloy.

R31 with RB on carbs see http://www.r31house....r31/vivi215.htm

#24 benny

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Posted 22 April 2010 - 06:37 PM

what about welding a aluminium box section over the whole rb cover then get that machined?? it could work with someone who knows there way around cad programming.

How good as you bro at it hunter??

#25 Hunter

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Posted 22 April 2010 - 11:56 PM

only problem with that benji is that the cam covers either side a seperate units, then the middle section is a plate of plastic that covers the coils/plugs is screwed to the insode of the cam covers.

So the inside cam cover bolts would not be accessed without drilling holes into the center of the machined part.

#26 Hunter

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Posted 22 April 2010 - 11:58 PM

nzeder thanks definite photo proove it can be done. and very close to the head which is good.

#27 Hunter

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Posted 23 April 2010 - 02:11 AM

Gav just to answer your question why?

It is not about power etc. It is about period correctness and trying to re-create an affordable 432 alternative.

Plus it will be different and fun, but I am not sure that you would call head F$@%$ and scun knuckles fun.

Also as far as getting it registered, if I can bonus, if not it will be a track only car and shows. Thing is the car I have just purchased used to have an RB25 installed, I will just keep the rego up and the cops won't know the difference down here. plus only transport have the power to open your bonnet, cops need a warrant.

#28 Hunter

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Posted 23 April 2010 - 02:44 AM

http://www.rockyauto...o/video003.html

this Skyline has carbs on it right? If so what brand?

#29 NZeder

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Posted 23 April 2010 - 07:30 AM

http://www.rockyauto...o/video003.html

this Skyline has carbs on it right? If so what brand?

Yes those are carbs and they are Mikuni/Solex type-2 versions. The type-2 were available in 36PHH, 40PHH, 44PHH and 50PHH so could be one of those sizes - depends on the engine and modes but my guess would be either 40PHH or 44PHH items.

#30 Hunter

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Posted 23 April 2010 - 10:39 AM

They do not make the Mikunis anymore do they? I would be better off going Webbers or Delortos I think, They come in 40mm and 45mm right? Also I think I seen a set on US Ebay that were 47mm but they would be far to big I think.

#31 twosixty

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Posted 23 April 2010 - 12:05 PM

They do not make the Mikunis anymore do they? I would be better off going Webbers or Delortos I think, They come in 40mm and 45mm right? Also I think I seen a set on US Ebay that were 47mm but they would be far to big I think.


Mikuni PHH bodies are no longer made. They still make plenty of other carbs. Not sure about the spares for PHHs.
Webers are still manufactured, though they are now made in Spain. Allegedly the quality is not the same as the original Italian product.
Dell'Ortos are no longer made, although parts are still reasonably available from O/S generally.
OER are still pumping out new sidedrafts and parts.

You can always choke down the larger bodies (to a degree)
With 40s you will probably be running close to the largest venturi (35-36mm?) that the 40s can hold.
With 44/45s you will have room to move up if needed.

#32 NZeder

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Posted 23 April 2010 - 12:55 PM

You can still get PHH parts new from Wolf Creek Racing in the US he even has NOS carbs for sale :)

If I was looking for carbs and wanted new I would get OER units from Japan - in fact I did on the my last 240z, they come in 45mm, 47mm and 50mm (I had the 47mm). The webers that are forsale these days are not like the old ones :( I think they are made in Spain now and the casting is not like it used to be :'(

Depending on the size of the engine you are planning to run 40's would be good on a RB20D, 44/45 on the RB25D up and if you are planning a RB30D then 45/47/50 with the right chokes will work 45 will be a little low for a big air moving high rev'n big power RB30D

Now what I could have done on my project was keep my OER 47, sold the DCOE throttle bodies, and then not blocked off the stock RB26 injector locations. Then I could run either with the flick of a switch - ie use the Carbs with no fuel as the TB and injectors for fuel. Then if carb power required, turn off the EFI pump, change the fuel pressure (could be controlled via a valve/solenoid to a lower pressure unit) and turn off the ECU/drop the fuel and have the ECU just do spark and turn on a Carb fuel pump.

Now that would be true hybrid lol

#33 Hunter

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Posted 23 April 2010 - 01:02 PM

Nzeder that hybrid idea sounds pretty good, I think I will just worry about getting carbs running though.

What are my options for running spark on the RB engine? ECU controlled or ????

I am looking for the simplest solution.

#34 NZeder

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Posted 23 April 2010 - 01:13 PM

Just spark you have a number of options - Mega Jolt (open source like MegaSquirt but just for spark control), just get a Ford Falcon EDIS 6 cylinder setup and hook that up to the MegaJolt. Or go for a more advanced setup like Electromotive, Motec, MSD, Autronic (they used to do just spark control) there are any number out there and then there is all the normal ECU that do Fuel and Spark just setup for spark only.

That will give you coil on plug or wasted spark setup. If you want really simple the issue will be getting a dizzy to work due to the location out the front = hit the radiator? And a good CID setup, Mellory, MSD, crane, the list goes on.

The simples spark setup would be EDIS type setup as no dizzy - did you know the MegaJolt R&D car is a 240z ;)

now stop making me think about this....or I might have to sell my DCOE throttle bodies and get some carbs and a MegaJolt/EDIS6 setup myself.

#35 NZeder

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Posted 23 April 2010 - 01:22 PM

One more thing you could use the factory CAS with a new chopper wheel as the crank angle 36-1 setup I believe it has been done before but might be quicker and easier to just install a standard hall effect unit and wheel on the crank pulley.

#36 NZeder

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Posted 23 April 2010 - 01:31 PM

One more thing one of reasons I went with a RB26 head was the factory vacuum block after the throttle bodies as this gives a good reference for the MAP. I just removed the FIDLE spider and other vacuum driven stuff from under the manifold - see my thread or website for more details/pics.

#37 Hunter

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Posted 23 April 2010 - 01:38 PM

Thanks for the info NZeder, You say to stop making you think about it. Then put too more posts up. lol

This project will be a bit on the back burner for me,  I will get my RB25DET up and road registered first.



#38 mad-max

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Posted 15 September 2010 - 07:04 AM

hiya guys  ;)

ive just finished my rb30s (carby) project so hopefully i can help you guys with a few things on this build
i have an rb30e in my hr31, last year i found a carby manifold and decided to jam it on befor xmas.... im runnin a standard carb manifold from a nissan patrol, with a falcon webber carb i took off a 4.1 litre falcon (just a dirty old 2 barrel around 300cfm), its now cammed up (290*Lumpy cam), and runs a 12lb flywheel and headers. very simple upgrades and ows me $300nz plus im not complaining yet  8)

Posted Image
(e/ i know the picture looks a bit shady but this photo was from when i first did it last year)

all that's needed to make it run was a vacuum advance dizzy..... with this i can run ANY carb i like if i could be bothered making new manifolds. triple side drafts are expensive and 4barrels cant be modified to fit the stock carby manifold but im sure would make a bit more of a difference.

as for using a dohc head id really like to see this done so if any of you figure out how to do this properly please "LET ME KNOW!!" (mad_max_hq@yahoo.co.nz)

heres what i do know about it.......
first things first your goin to have alot of trial and error testing out ways to make it work (like i already have)
second of all the cam angle sensor will work with out any of the other sensors plugged in and with out the injectors plugged in .... ie exhaust sensor, afm, and tps
i know this because if you unbolt the cas and spin the shaft you can physically watch the spark do its thing in sequence and its a good way to test for spark :P

ive also ran the engine for a short time on start ya bastard haha..... i had no sensors plugged in except the cas and of course no injectors.
only thing im not sure about is it would have only ignition timing with no advance (or just set it to around 25-30*advanced hahaha) and where it advances from. im pretty sure the timing advance is done at the ecu depending on a few variables
eg. throttle position, afm,
but possibly if we're lucky it just does this on revs from tacho signal from the cas

so for a start id just do it!! its goin to work with the standard ecu & cas and is really one of the only ways to find out if it advances at the ignitor pack. if it advances at the ignitor pack/ecu with out the use of other components your done  ;D eeezz peezzy
if not probably best bet is an msd ignition or simaller

sorry bout my SA hopefully this helps and also if anyone can give a second opinion on the ignition side of things it would be a big help.
basically these two questions.....where is advance controled? and what variables does the ecu need to advance the timing?


#39 RB30X

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Posted 15 September 2010 - 07:39 AM

Factory ecu variables to advance spark would be engine temp. Are you finding that it feels sluggish or retarded and you want to try it advanced more? You can just increase your base timing and see how it goes then. Remember these spin opposite to l series engines. What dizzy did you use?  I think you are a legend for attempting to do this and succeeding. The latest performance imports mag has a few writes up of old jap workshops including rocky auto who they say is doing a lot of na rb30 engines these days. I want to build an na rb30 with dcoe carbs. That would be saweet.

#40 mad-max

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Posted 15 September 2010 - 01:56 PM

rb30x ... if its an rb30e you wish to run with carbs heres a quick guide.... just try and find an original vac advance dizzy through nissan or something thats what im using but i was lucky enuff to get it with the manifold..... they are very hard to find parts for but they do use the same cap and rotor (cut 5mm off the bottom of the rotor so its usable)
you could import a dizzy from south africa, the sgli r31 skyline from south africa uses the rb30s.... they also come out in rb24s in the philipino a31 cefiro, Nissan GQ Patrol and ford mavericks are the same and use an rb30s and as far as i know ford mavericks were being made up untill 1995 using the rb30s

(if you look in the pic the loom is bundled up in the corner  :P )
Posted Image

thats a nice choice of carb and will work very well with headers, a decent cam, and a shaved head.... i wouldnt do much more than that no matter what any one says (apart from lightning pullys/flywheel ect and maybe do the valve springs)
doin any more work in my opinion would be a waste of time/money

carbs do have there ups and downs tho....
-there simple
-you can use a much more wild cam than on an injected engine
-easier to work on the engine (getting at spark plugs is not a problem anymore :D )
-no loom or ecu
-uses alot of gas
-secondaries (for the kick in the seat fealin)
-power is alot different
-lack of power at low rpm
-about 20-25 kilo (maybe more) weight reduction

id also like to point out that it purrs like a kittin with rb30e cams and it started first pop no trouble just like all good rb's should..... im also yet to find another n/a rb30 that will beat it in a straight line

and heres me babbling sh#t again





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