bought a 71 datsun 240z and i dont know anything about carbs

[zKars]

Arne, thanks for the clarification. All 260's were flat top carbed. No FI. thanks!

[Carl Beck]

Hi Albert:

First - as others have mentioned - a 240Z Factory Service Manual is the best thing to have.

Second.

See this picture - you can see where the vacuum hose hooks up for the distributor vacuum advance.

http://becksystems.com/KellyW/162KellyW.jpg The vacuum advance on the distributor uses Ported Vacuum just behind the Carb - ahead of the intake manifold.

Third - the hose off the top of the Carb Float Bowls is a vent - it would normally hook to the stock Air Cleaner - but as I recall the aftermarket round cleaners have a hole in the back of them for a connector. I wouldn't suggest venting the float bowls toward the exhaust manifold.

Fourth - the last picture shows a line from the Gasoline Vapor Emission Flow Control Guide Valve - that used to run to the Stock Air Cleaner - that line lets fresh air into the system, to allow heavy gasloine vapors to get out of the cannister in the rear of the car - - - Unplug that and leave it open. No need for the hose if it isn't connected to an air cleaner

Fifth - the vacuum ports on the Balance Tube - between the Carb's - should be properly sealed off if not used.

Post some pictures of the rest of the Z - and tell us why you bought it to begin with.

FWIW,

Carl B.

Edited October 10, 2012 by Carl Beck

[03redzo6]

First of all, welcome to the club! Secondly, check out the SU-carbs section in this forum and use the search function, there is tons of info here for you to find. It seems you are missing the tube from front carb to distributor, it suppose to be attached on the manifold side of the carb. Other 2 tubes from the carbs supposed to be attached to original style airbox.

Btw. you have exactly the same coil as i do

Thank you, and will do. I hooked up the distributor vacuum to the carb manifold but I didn’t notice any change in anything.

Hi Albert.

Koalia is correct. There should be a vacuum hose from the inlet manifold to the distributor.

Where does the hose in the last picture come from? If it comes from the inlet manifold, then remove the bolt, and determine if there is suction there with the engine running.

If it doesn't, then attach a hose from the unused fitting near the centre of the manifold to the dizzy.

Idle should be 7-800 RPM or thereabouts.

Haynes put out a good book---DATSUN 240z & 260Z OWNERS WORKSHOP MANUAL. Lots of good reading there.

Your engine has carbs from a 240Z, which will run well. Someone has swapped in a 260 and put 240 carbs on there. Originally 260 was fuel injected.

Hoses from the carbs are merely breathing tubes, and as Koalia said were plumbed into the air cleaner box.

Tie them away from the exhaust, and shorten them a bit if you want.

Brian.

Hello, I unplugged it but there is no vacuum or air coming out. It seems to be coming from this blue tube that’s connected to the block. I’ll be getting a haynes book then, thanks. I got the idle down to 950rpm but any lower and the car shuts off.

There were two different 260's in North Am. Early one with flat top carbs like 73 240 (though not identical), skinny bumpers with hydraulic shocks, and then a later one with FI like 280 and bumpers like the 75 280. The interiors for both were the new 280 style dash and console. Real Heinz 57.... No wonder folks restoring 260's have a devil of time finding parts for them!

Nice Z BTW. I like the red wire that comes through the firewall at the choke cable grommet and goes to the coil best. I'm pretty that's not stock... and worth understanding what it bypasses (like the ignition switch....).

Thanks for the heads up, I’ll look into it. This car came with a push start button, but I want to uninstall that.

Download the FSM from the "Reference" section of xenons30.com, everything you need is in there. The Haynes book is woefully underwhelming.

I’ll go ahead and do that, thanks.

We sell a dvd that will help shorten your learning curve on the Hitachis (SUs made under license for the Japanese makes). You could for very little money go through them, clean 'em up and get them running in some known state to see what you really have.

JUST SUs ZTV09 for twenty five of your hard earned dollars.

Whatever you do don't plug the hoses that come off the top of the float bowl lid. Those need to be open to the atmosphere. Is there anything hooked to the vacuum advance canister on the distributor? Are you running a points distributor of and electronic distributor. If you are running an electronic distributor and there is no vacuum advance hooked up at the canister it may be because the EI Dist was over advancing with vacuum hooked up..

I’ll go ahead and order one today, thanks. There wasn’t anything hooked up to the vacuum advance canister but I hooked it up to the carb manifold but didn’t notice any change. I’m not sure if this picture will help with your question but here it is.

[Carl Beck]

Second Picture from the last at Post #15 - the Top hose on that Flow Control Valve should go to the Air Cleaner or be left open - it draws in fresh air. The Bottom hose goes to the Crankcase Vent... the flow control valve directs gasoline vapors to the crank case - where they are sucked back into the intake manifold by the PCV valve.

FWIW,

Carl B.

[03redzo6]

Hi Albert:

First - as others have mentioned - a 240Z Factory Service Manual is the best thing to have.

Second.

See this picture - you can see where the vacuum hose hooks up for the distributor vacuum advance.

http://becksystems.com/KellyW/162KellyW.jpg The vacuum advance on the distributor uses Ported Vacuum just behind the Carb - ahead of the intake manifold.

Third - the hose off the top of the Carb Float Bowls is a vent - it would normally hook to the stock Air Cleaner - but as I recall the aftermarket round cleaners have a hole in the back of them for a connector. I wouldn't suggest venting the float bowls toward the exhaust manifold.

Fourth - the last picture shows a line from the Gasoline Vapor Emission Flow Control Guide Valve - that used to run to the Stock Air Cleaner - that line lets fresh air into the system, to allow heavy gasloine vapors to get out of the cannister in the rear of the car - - - Unplug that and leave it open. No need for the hose if it isn't connected to an air cleaner

Fifth - the vacuum ports on the Balance Tube - between the Carb's - should be properly sealed off if not used.

Post some pictures of the rest of the Z - and tell us why you bought it to begin with.

FWIW,

Carl B.

Thank you, that picture was very helpful. ill check later for the hole in the carb filters. As far as the line from the Gasoline Vapor Emission Flow Control Guide Valve, would it be ok if i found a way to hook that up to the carb filter, or should i just leave it alone and unplug it.

Ill take a picture of it later and post it but i have to warn you, it needs a lot of work, but at least it runs. Im 26yrs old now and i first saw one of these cars when i was about 8yrs old, i remember it looked so cool, after that i never saw another one again. I sold my 03 Z06 a couple of days ago so i can use that money for a down payment on a C6 Z06 but i couldnt resist, so i picked up this little thing as a project so i can restore it to its former glory.

[Carl Beck]

Thank you, and will do. I hooked up the distributor vacuum to the carb manifold but I didn’t notice any change in anything.

You shouldn't. At idle there is no need for vacuum advance in the distributor. You should feel vacuum on that line if you open the throttle and run the engine at higher RPM's. Vacuum Advance should advance the timing under load and back off at cruise or steady RPM's.

Hello, I unplugged it but there is no vacuum or air coming out. It seems to be coming from this blue tube that’s connected to the block.

That Blue Tube is the Crankcase Vent - the small tube on it - should be hooked to the bottom line on the Flow Control Valve. It is there to suck gasloine vapors into the crankcase.

FWIW,

Carl B.

[Walter Moore]

We sell a dvd that will help shorten your learning curve on the Hitachis (SUs made under license for the Japanese makes). You could for very little money go through them, clean 'em up and get them running in some known state to see what you really have.

JUST SUs ZTV09 for twenty five of your hard earned dollars.

Whatever you do don't plug the hoses that come off the top of the float bowl lid. Those need to be open to the atmosphere. Is there anything hooked to the vacuum advance canister on the distributor? Are you running a points distributor of and electronic distributor. If you are running an electronic distributor and there is no vacuum advance hooked up at the canister it may be because the EI Dist was over advancing with vacuum hooked up..

I second everything that Bruce said. Maybe I am dense, but I couldn't get my head around the SU until I saw the video.

[Carl Beck]

Thank you, that picture was very helpful. ill check later for the hole in the carb filters. As far as the line from the Gasoline Vapor Emission Flow Control Guide Valve, would it be ok if i found a way to hook that up to the carb filter, or should i just leave it alone and unplug it.

Yes - it would actually be best if hooked to the carb air cleaner. If not - it at least has to be open to draw in fresh air.

I'm sure that you will enjoy the Z - they are fun to drive and very easy to work on. Once they are in proper condition - they are very reliable as well. Not to mention that they are always beautiful to look at.

FWIW,

Carl B.

[bpilati]

You shouldn't. At idle there is no need for vacuum advance in the distributor. You should feel vacuum on that line if you open the throttle and run the engine at higher RPM's. Vacuum Advance should advance the timing under load and back off at cruise or steady RPM's.

Hello, I unplugged it but there is no vacuum or air coming out. It seems to be coming from this blue tube that’s connected to the block.

That Blue Tube is the Crankcase Vent - the small tube on it - should be hooked to the bottom line on the Flow Control Valve. It is there to suck gasloine vapors into the crankcase.

FWIW,

Carl B.

Carl, why would you want to suck gasoline vapors INTO the crankcase?

[Carl Beck]

Personally I wouldn't want to. However as part of the Gasoline Vapor Emission Control System - gas vapors from the tank are collected in that cannister behind the Right Rear Quarter. That cannister is there to allow the vapors to condense back into liquid form when they get dense enough. The vapors that remain are sent up to the engine compartment - to that Flow Control Valve. They are sucked into the crank case when there is a negative pressure there - then redirected to the intake via the PCV system - to be sucked into the combustion chamber. So the crank case is just a place to suspend them until they can be put back into the combustion process.

This was all originally part of the California emissions control regulations - but soon became part of the Federal Standards.

Give a bureaucrat an inch and they will always take a mile and demand more. They can not ever let their job be DONE.

FWIW,

Carl B.

Edited October 11, 2012 by Carl Beck

[Jonu]

Personally I wouldn't want to. However as part of the Gasoline Vapor Emission Control System - gas vapors from the tank are collected in that cannister behind the Right Rear Quarter. That cannister is there to allow the vapors to condense back into liquid form when they get dense enough. The vapors that remain are sent up to the engine compartment - to that Flow Control Valve. They are sucked into the crank case when there is a negative pressure there - then redirected to the intake via the PCV system - to be sucked into the combustion chamber. So the crank case is just a place to suspend them until they can be put back into the combustion process.

This was all originally part of the California emissions control regulations - but soon became part of the Federal Standards.

Give a bureaucrat an inch and they will always take a mile and demand more. They can not ever let their job be DONE.

FWIW,

Carl B.

So if you aren't worried about emissions, you could rip all that stuff out and just plug the vent tube @ the tank?