Charcoal canister?, With carbs what do I need?? Options

[nivekdodge]

I have carbs on the car and ifs been ran around the block a few times. The guy I bought it from removed everything he could with hand tools and put the parts on eBay. It’s a 74 with a 1.8 and like I said, carbs…do I need the canister? What should my fuel system look like?

Kevin

[SirAndy]

There was a thread on that very topic just a week or two ago.

In my opinion:
Yes, install the whole evap system. You will appreciate the lack of fuel smell.

(IMG:style_emoticons/default/popcorn[1].gif)

[r_towle]

Well, the evap system on a car is to keep the raw evaporated fuel from going out into the atmosphere.

You do not want to block off the ports at the tank, because fuel expands and contracts with heat, so it needs to be vented or it will become possibky a dangerous issue.

So, old school carbbed cars from 1900 up to 1960/70s used to just have a vent tube running out under the car.

Modern cars take that gasious stuff and inject it into the intake to be burned.

If the hoses still exist on the drivers side, underneath the rocker cover, you can add a charcoal canister either up front on top of the tank, like 70-74, or put the charcoal canister into the engine bay like 75/75 cars.

Hoses from tank to canister
Hose from canister to carbs
Hose from engine fan to blow air into canister, thus blowing gas fumes into carbs.

Gonna need some enclosed air filter boxes with a fitting to attach the hose

[wonkipop]

Well, the evap system on a car is to keep the raw evaporated fuel from going out into the atmosphere.

You do not want to block off the ports at the tank, because fuel expands and contracts with heat, so it needs to be vented or it will become possibky a dangerous issue.

So, old school carbbed cars from 1900 up to 1960/70s used to just have a vent tube running out under the car.

Modern cars take that gasious stuff and inject it into the intake to be burned.

If the hoses still exist on the drivers side, underneath the rocker cover, you can add a charcoal canister either up front on top of the tank, like 70-74, or put the charcoal canister into the engine bay like 75/75 cars.

Hoses from tank to canister
Hose from canister to carbs
Hose from engine fan to blow air into canister, thus blowing gas fumes into carbs.

would have to be a very early 74 1.8 to have the hoses n the rockers.


Gonna need some enclosed air filter boxes with a fitting to attach the hose

most 74 1.8s don't have the hoses in the rockers.
they have the engine bay can and only run the small diam fume hose down the centre tunnel to the engine bay.

anything built after nov 28 73 will be engine bay can.
there is only about 3 weeks of 1.8 production with the front trunk can beginning in late october 1973.

kind of makes it a little easier to do with the engine bay can set up.
esp if the fume line still happens to be there in the centre tunnel.

(IMG:style_emoticons/default/beerchug.gif)

[nivekdodge]

Thanks for the response,

Wonkipop,
What is the center console fume line made of?

Kevin

[wonkipop]

Thanks for the response,

Wonkipop,
What is the center console fume line made of?

Kevin

its very small diameter. and black plastic.
i don't have a measurement or size but its very small, like you know 5mm diam at most.
it runs in the tunnel with the fuel lines, clutch cable etc.

two easy ways to tell if you got it.
what is the build date on your car?
its on the vin sticker in the drivers door jamb.
if you are after nov 73 or late nov 73 it originally had the fume line going through the tunnel.

also if the fume line is there in the tunnel it will be exiting out of the tunnel under the engine on the back passenger firewall near the fuel lines.
whoever did the carb conversion might have just chopped it off after the firewall if you are lucky. or they might have pulled the whole thing out.
but get under the car if you can and look around where the fuel lines exit the tunnel.
if the fume line is still there it will be close to them.

[wonkipop]

Well, the evap system on a car is to keep the raw evaporated fuel from going out into the atmosphere.

You do not want to block off the ports at the tank, because fuel expands and contracts with heat, so it needs to be vented or it will become possibky a dangerous issue.

So, old school carbbed cars from 1900 up to 1960/70s used to just have a vent tube running out under the car.

Modern cars take that gasious stuff and inject it into the intake to be burned.

If the hoses still exist on the drivers side, underneath the rocker cover, you can add a charcoal canister either up front on top of the tank, like 70-74, or put the charcoal canister into the engine bay like 75/75 cars.

Hoses from tank to canister
Hose from canister to carbs
Hose from engine fan to blow air into canister, thus blowing gas fumes into carbs.

Gonna need some enclosed air filter boxes with a fitting to attach the hose

its not just about expanding fuel.
its actually how the tank vents as you draw fuel out, so it does not develop a vacuum.
equalises pressure.

the charcoal can was the original cheap and cheerful tank pressure equalisation "valve" when it came to VWs and VW/Porsches. quite interesting how they did it compared to other manufacturers who used a real valve. sort of a passive system is how i would describe it. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beerchug.gif)

[r_towle]

I’m digging into my 911 which has two different canister type things but odd placement adds fuel smell in the car. It’s 40 years old, gonna replace most of it

[nivekdodge]

Funny , I asked that question and then realized I have a metal tube in the tunnel that's real small. That must be it or it will be it.

Thanks again
Kevin

[porschetub]

Funny , I asked that question and then realized I have a metal tube in the tunnel that's real small. That must be it or it will be it.

Thanks again
Kevin

Maybe but think it will be the unused fuel return line which if on carbs isn't needed.

[wonkipop]

Funny , I asked that question and then realized I have a metal tube in the tunnel that's real small. That must be it or it will be it.

Thanks again
Kevin

trying to remember.
it was 4 years ago.
i replaced the fuel lines with metal.
to the best of my memory its a single plastic tube (black plastic) runs all the way through. comes out a grommet in the back fire wall and it goes through the fuel line grommet in the front fire wall with the fuel lines. it comes up near the fuel tank and you plug it into the fabric hose coming from expansion tank. at the back firewall it goes right in the direction of the fuel lines and feeds up through the engine shelf - once in the engine bay it makes its way around the canister which in 74 hangs off the trunk side firewall. again a short bit of fabric tube sleeves the connection to the can.

to the best of my memory the plastic tube/hose is there in the tunnel. its not a metal tube. but maybe it feeds down through the tube you have found so its not lying loose.
to be honest i paid it little attention as i left in place at the engine firewall end. and fed it back through the grommet at the front firewall. would make sense its fed up a tube to keep it out of mischief. but i can't say for sure as i was not really looking at it. too busy tearing my hair out fabricating my fuel lines and trying to get them to test fit (one of the miseries of a right hand drive 914). (IMG:style_emoticons/default/biggrin.gif)

where it emerges under engine is just to right of the second fuel line grommet.
small diam hole. if this metal tube you have found aligns with that hole then it probably does feed through the metal tube you are talking about.

the correct diagrams are here in originality section of world website.

link. scroll down and you will find engine bay diagram.
http://www.914world.com/bbs2/index.php?sho...57407&st=40

might be hard to find room to mount it in original 74 position with carbs.
might be in the way. another possibility is to mount off battery tray as per 75 cars.

[wonkipop]

I’m digging into my 911 which has two different canister type things but odd placement adds fuel smell in the car. It’s 40 years old, gonna replace most of it

yeah - i know the 911s of the same era as the 914 had more going on.
they seemed to have an expansion chamber and a vent chamber separate from each other. the vent chamber was plumbed into the expansion chamber and the expansion chamber plumbed to the charcoal can. think it had something to do with the low lying fuel tank and much longer filler neck compared to a 914. the way the 914 expansion chamber comes up higher than the filler cap which sits in a depression kept the whole thing a lot more KISS in a 914. beetles had to have something a bit like a 911 to update their tanks for the evap system regulations as well. a kind of adaption to a design that dated from a decade earlier.

[Dustin]

Sorry to go off on a tangent here. But, see 26 29 and 30? One connects to the canister. The canister connects to the air box. What do the other 2 lines connect to? This has just started bothering me today. I think I'm missing the T. I also think I only have the one line that connects to the canister in my engine compartment. I do have 1 vacuum line that is open on one end in my engine compartment. Because that's how the diagrams I've found show it. Even if my open connection is part of this system. There's still an extra line in this diagram.

[ClayPerrine]

Sorry to go off on a tangent here. But, see 26 29 and 30? One connects to the canister. The canister connects to the air box. What do the other 2 lines connect to? This has just started bothering me today. I think I'm missing the T. I also think I only have the one line that connects to the canister in my engine compartment. I do have 1 vacuum line that is open on one end in my engine compartment. Because that's how the diagrams I've found show it. Even if my open connection is part of this system. There's still an extra line in this diagram.

28, 29 and 30 are for cars delivered without a charcoal canister system. Other than early sixes, all of the US spec 914s had a charcoal canister.

Even the early sixes had one if they were sold in California.

[Dustin]

I believe there are 2 hoses coming off my expansion box. Just like in the picture. One attaches to the canister 35. I'm not sure where the other one goes. I'd have to look. Even if they're for cars without canisters they still attach somewhere.

[ClayPerrine]

I believe there are 2 hoses coming off my expansion box. Just like in the picture. One attaches to the canister 35. I'm not sure where the other one goes. I'd have to look. Even if they're for cars without canisters they still attach somewhere.

Hose #26 attaches to the filler neck.

Hose #27 attaches to the small fitting on the canister.

The two big hoses attach to the fan housing and the air cleaner.

[wonkipop]

I believe there are 2 hoses coming off my expansion box. Just like in the picture. One attaches to the canister 35. I'm not sure where the other one goes. I'd have to look. Even if they're for cars without canisters they still attach somewhere.

(IMG:style_emoticons/default/biggrin.gif)
yeah the PET diagrams are not exactly "clear". (IMG:style_emoticons/default/biggrin.gif)

this is how it works on USA cars dustin.

there is a little hose on left hand side of expansion tank just under the top.
(by left hand side i mean standing at front and looking towards rear of car).
it is a short length and curls back towards the gas cap, it hooks to a nipple on the short length of filler tube under gas cap.

the nipple on the right hand side of the expansion tank goes off to the charcoal can.
in a pre late nov 73 car that can is on top of the petrol tank and is also connected to hoses running from the engine bay. one hose to fan casting for air bleed. one hose to the aircleaner for fume conbustion

in a post late nov 73 car the charcoal can is in the engine bay. the fume line from expansion tank goes down the centre tunnel of car with the fuel lines.

the overflow tube on the fuel tank is a larger diameter clear plastic hose.
it connects to the open spill tray at the filler neck. it is part #43/1 in the diagram as clay has pointed out.

its a very confusing diagram because it explicitely shows the rest of world set up for the expansion tank. but it does not show the USA diagram when it comes to the expansion tank. (IMG:style_emoticons/default/beerchug.gif)

[Dustin]

Where does 30 go though? That's really my question.

[wonkipop]

Where does 30 go though? That's really my question.

well i don't have a euro car.
and its been 30 years since i have seen one.
30 is only on the euro.
but its their idea of a fume line. ie both the lines on a USA car, one of which is just a loop to the filler neck and one to the can instead feed into that with a T.
i would say its fed out through the access hole under the fuel tank for fuel line connection access.

the car i saw was converted by crayfords in london to rhd.
and mine is a local conversion. in my car and that car that access hole virtually disappears in the conversion. it gets cut right into.

in our cars the overflow is fed out through the rhs mudguard because the normal left hand drive hole for overflow is down in the section of firewall that is removed for rhd.
so, not really sure what a left hand drive original car has down there.
def has the same hole for the overflow/overfill tube in euro and USA cars.
whether there is another small hole down there for feeding the vent tube or whether a seperate smaller hole was provided for the vent tube, not sure.
perhaps if you look under your lhd cars to see if there is a universal hole and they just sealed it with a grommet? if not they must have fed it through the access hole for fuel line connection.

[r_towle]

Ok, lots of word, smart though they may be… total compliment.

30 goes down the back of the tank through a hole right next to the 3 inch diameter hole.
It’s an overflow line, clear plastic.
PP, AA, and PMB sell it.