dual carbs

[Laecaon]

Ask converted to datsuns. He has those.

[datmo]

Ask converted to datsuns. He has those.

i cant find his name. lol ill look more

[Laecaon]

http://nwdatsuns.com/memberlist.php?mod ... ofile&u=96

[datmo]

http://nwdatsuns.com/memberlist.php?mod ... ofile&u=96

Perfect.
I'm gonna ask around on ratsun to see if i can get a quicker reply.

[Converted_to_datsun]

Go your pm and figured I'd drop an engine bay pic here after I replied haha

[datmo]

So i found the carb filters which are exciting as hell but then i came to then installation part

i have to unbolt my headers and then i was told i need a new gasket?
does anyone know where I could get these?

[Laecaon]

napa... its just a manifold gasket...

[datmo]

napa... its just a manifold gasket...

http://www.napaonline.com/Catalog/Catal ... 0300383082

These should do the trick?

sorry for the questions and all. just wanna get ready to do it all correctly. haha.

if im not mistaken from what i read, i have to tune the carbs to the precise same thing for the car to idle on its own, right?
my car does not idle on it's own at the moment but when i put in the duals, I plan to make it so.

[Converted_to_datsun]

No... You have to put the year and model of your car to find the right ones...

[datmo]

No... You have to put the year and model of your car to find the right ones...

shows how much of a nub i am. lol

http://www.napaonline.com/Catalog/Catal ... 0147223652

[Converted_to_datsun]

Ok now you're cooking! Haha that one will work

[datmo]

Ok now you're cooking! Haha that one will work

to tune the carbs, I found this off ratsun...
http://www.teglerizer.com/sucarbs/techtip6.htm

I gotta read this thing more.

i wish they had tuning su's for dummys though. hahah.
I'm excited to get my swap done.
Then i can get my swap and matchbox dizzy swap done the coming weekend.
get my license monday and then get my rear coilovers the next weekend. haha

[wayno]

Hey datmo, you need an air meter to start with, some will say you can do it other ways, but let us face it, you are new to these carbs, why make it harder than it needs to be.
http://www.ebay.com/itm/Uni-Syn-Edelbro ... e4&vxp=mtr
In the photo below you can see a screw just above the yellow vacuum plug on the carb, this screw is how you balance both the carb with the airflow meter, each carb has this screw, you can see both of them in the photo below.

This is a photo of my SUs below, see the springs on the shaft that has the hoses connected to the bottom of them, the round ridged nut is the fuel mixture adjustment, the thin nut above the spring should not be touched under any circumstance other than a complete rebuild of the carbs

See in the photo above how my springs are not compressed the same on both carbs, well after 15 years of daily driving, they are just about worn out, but yours hopefully will be even, these round ridged nuts are how you fine tune the fuel mixture, right now you need to get it running, you do not need to start worrying about the needles for fuel mixture, I have never changed my needles in 15 years, and my engine runs fine, and believe me when I say I use my truck hard, do not worry about the freaking needles, and absolutely do not touch the needles for any reason.
Once you get it started(leave everything the way it is adjusted when you get them), you will first balance the carbs using the air flow meter, see the only brass collar on the throttle linkage above, the screw next to it should be loose, once the carbs are balanced that screw is adjusted so that both carbs move at the same time when you give it the gas, you can adjust this screw last if you want.
Next what you do is disable one of the carbs at a time, you do this by lifting the piston slightly with your finger, or there is a lever you push up on on the bottom of each carb that does the same thing, then you tighten each fuel mixture screw(ridged round nut) until the engine starts loping, but not so tight that it dies, if the engine dies, it is to lean, once you have it evenly loping, you disable the other carb and do the same thing till it lopes exactly the same, when you disable each carb and it lopes even/the same without dying, then your fuel mixture is the same.
After you drive it a while, you can fine ture the mixture by removing the spark plugs and checking the color, if they are black, it is rich on the front two cylinders try tightening that carb fuel mixture a little, if it is to white, then you might make it a little richer, mostly what you want is all 4 plugs to look the same.
Do you understand what I just described above?
There are as many ways to adjust these carbs as there are people with these carbs, I used the hayes or chiltons( I cannot remember which I used) manuals for my directions on how to adjust SUs, and they have worked just great for all these years, it's not that complicated.

[wayno]

Ok now you're cooking! Haha that one will work

to tune the carbs, I found this off ratsun...
http://www.teglerizer.com/sucarbs/techtip6.htm

I gotta read this thing more.

i wish they had tuning su's for dummys though. hahah.
I'm excited to get my swap done.
Then i can get my swap and matchbox dizzy swap done the coming weekend.
get my license monday and then get my rear coilovers the next weekend. haha

As I said, there are as many ways to adjust these carbs as there are people with them, my post above is a general decription on how to adjust them, you have to fill the carbs with the proper oil, the float levels need to be the same, but since the guy said it was on a running engine, then I see no reason to rebuild them before trying to start them, I repeat, do not touch the needles mounted in the plunger for any reason, you can bend them by picking them up off a desk.

[datmo]

Ok now you're cooking! Haha that one will work

to tune the carbs, I found this off ratsun...
http://www.teglerizer.com/sucarbs/techtip6.htm

I gotta read this thing more.

i wish they had tuning su's for dummys though. hahah.
I'm excited to get my swap done.
Then i can get my swap and matchbox dizzy swap done the coming weekend.
get my license monday and then get my rear coilovers the next weekend. haha

As I said, there are as many ways to adjust these carbs as there are people with them, my post above is a general decription on how to adjust them, you have to fill the carbs with the proper oil, the float levels need to be the same, but since the guy said it was on a running engine, then I see no reason to rebuild them before trying to start them, I repeat, do not touch the needles mounted in the plunger for any reason, you can bend them by picking them up off a desk.

Thanks man. Honestly that was too kind of you!
I think I'll def try to tune the single carb I have at the moment just to some what get used to it or learn and then I can do the dual carbs hopefully. if not, my uncle said he'd do it for me but then he won't really teach me...

Thanks a lot wayno!

and i just purchased my two hs2 air filters that converted showed me!

[datsunmike]

Well this is quite a lot to bite off and chew. Installing a manifold and tune for running not one but two unknown SUs?

Do you have the choke cables with these?
Are the slides free to move?
Damper oil?

I see they have at least been de-smogged. What's the history on these? What were they run on?

[datmo]

Well this is quite a lot to bite off and chew. Installing a manifold and tune for running not one but two unknown SUs?

Do you have the choke cables with these?
Are the slides free to move?
Damper oil?

I see they have at least been de-smogged. What's the history on these? What were they run on?

I won't be using a choke since I'm never really in areas that cold.
Everythign is free to move.

What's sketchy is they've been sitting for 3 years but came off a guys 510.

[datsunmike]

SUs don't have accelerator pumps so you can't pump the gas to start them.

[Sealik]

Well this is quite a lot to bite off and chew. Installing a manifold and tune for running not one but two unknown SUs?

Do you have the choke cables with these?
Are the slides free to move?
Damper oil?

I see they have at least been de-smogged. What's the history on these? What were they run on?

I won't be using a choke since I'm never really in areas that cold.
Everythign is free to move.

What's sketchy is they've been sitting for 3 years but came off a guys 510.

If the engine has been sitting over night...you're probably going to need choke cables to fire it up.
It's not a typical carb where you hit the gas pedal a couple of times to shoot some fuel into the intake.
Choke cables lower the seats away from the needles enabling the motor to draw more fuel out of the seats.
....<.....Rich mixture for 'cold starts'
No fuel...no fire

[wayno]

These carbs have chokes on them for a reason, and it's not for looks, as said above, these do not have any type of accelerator pump, you cannot pump the pedal and expect it to start as no gas is pumped into the intake, you really do need a choke cable for dual SUs, I use mine year round, hot or cold outside when starting it for the first time that day, otherwise it will turn over for extended periods of time before it might try to start, it should start within 3 seconds with a choke, not 10 seconds or more.
I even use the choke when it sits for 7 hours(time it takes to do a job), mine will not start cold, but I try not to run it rich either, when I pull my spark plugs, I want to see a slight white/yellow color, not black(rich), if I see black, I lean out that carb even more, that is why mine are not even close to the same now, the back carb runs rich.

As I said before, you should use the weber you have, but you cannot tune a weber like you tune SUs, webers are made different, for the most part, either they work great, or they don't run good at all, I personally don't like down draft carbs, but that's just me.