MK1 Fueling issue

[Mk1Golf]

Just doing the final settings on the dellorto carbs I have on the MK1 and noticed a not ideal issue.
On these carbs there is no fuel return line so the old return line that was originally used with the VW Carbs is now redundant, the issue is that because it is still attatched to the tank each time you run the motor fuel leaks out of it, which is pretty dangerous!! Now if i blank it off then the tank cannot vent and it will suck itself in, so I wondered if i need to fit a one way tank vent on this line to cure the issue or have other people had this same issue and found an alternative?

[vwrally]

If your delortos are side draught then you need about 3lb max fuel pressure at the float needle seats which means you will need a Fuel pressure regulator.

To bleed off the excess pressure this needs to be teed to the the return hose there by eliminating your current problem and your next problem of the car over fuelling

Out of interest what jet sizing are you using

[Mk1Golf]

Great, so I need to get a T-piece for the fuel return, do you mean teed off at the regulator or from the carbs? and if it's at the carbs do you know who may supply the correct dellorto one in NZ?

Not sure what size jetting I have as I bought the carbs ready and set up to run on a 2.0 motor, I have a Holly FPR set at 2.5psi.

If you really want to know the jet sizes I can take them out and have a look if you like?

[vwrally]

I will try and do a picture tomorrow of how it should work, dont panic re jet sizes just curious

[Mk1Golf]

Thanks mate.

[BB]

Your mk1 tank will vent through th fuel cap and it will not become a vacuum and suck on the return line.
 I would say if you gave the return line a blow you would rid it of any residual fuel and you wont get any leaking again.
 Just shove a bolt down it or something.

 My girls mk1 has a webber carb on it and whilst somebody did do a return arangement on it (badly) it dosen't seem to run right as I think it to needs a little pressure.
 The old mk1s had a terrible little plastic T piece in the line that would break and people ( i did) would replace them with a T peice from the auto shop but the real VW was different as it had a restricted hole going to the return thus ensuring correct flow to the carb.
 The car would go but then on a steep hill conk out, like the bridge

 Any way I have just bent the fuel line over in half to block the return on the girls car, no probs. 

[vwrally]

Hi Mk1 Golf

I cant find a picture but basically you need to tee off the main feed line to the return line with a Fuel Pressure regulator in the branch from the feed to the return line. This will ensure that the pressure to the carbs is as per the regulator setting. I would increase the pump setting to 5-6 lbs and let the regulator control it.


Depending on how far away the pump is you will get line loss resulting in lowr pressure at the needle seat and the pressure settings on pumps arent very accurate in my experience

I have done as BB says above and destoryed a set of rings pretty quickly as it over fueled the motor and reduced the lubrication in the bores.  The bore wear was pretty excessivs as well. Motor was knackered in 30,000k's. That was using a carb jetted for a 2 litre motor as well. But s**t did it go 

[Mk1Golf]

OK, so what I did today was at the holly regulator you have a feed in from the tank, then two outlets one I have sent back to tank via the return line, the other feeds both carbs, is this what you meant vwrally?
Hope it is and all I will need to do tomorrow is increase the pressure as you said cos at the moment in hesitates slightly and the carbs pop back.Timing is all good and they are balanced (drawing same amount of air)
Thanks.

[vwrally]

, is this what you meant vwrally?

Yep, those holley regulators are great, but you need to check the output pressure with a gauge if you can

Is the hesitation on acceleration, maybe the accel pump jets.

The accelerator pump cuircuit gets a hard time on golf motors due to the heat generated by the exhaust, it doesnt do the diaphragms any favours

Try to shield the heat as much as possible from the bottom of the carbs

[Mk1Golf]

Yeh on acceleration, but if you are steady on the pedal it's better, I wondered if it is to lean or maybe overfueling.
I checked the pressure today and it was nearer 2psi than 2.5, so maybe i need to increase the pressure a bit?
It went really well until i dropped the pressure so i reckon its running a bit lean under load.

[vag_nutter]

What does it go like on twin sidies?

[Mk1Golf]

Goes like a rocket when they are set right, but they are bitch to setup without a rolling road or analyser.

[Mk1Golf]

Yep, those holley regulators are great, but you need to check the output pressure with a gauge if you can

Is the hesitation on acceleration, maybe the accel pump jets.

The accelerator pump cuircuit gets a hard time on golf motors due to the heat generated by the exhaust, it doesnt do the diaphragms any favours

Try to shield the heat as much as possible from the bottom of the carbs

I have a heat shield on the exhaust manifold but still gets really hot, not a great setup really, but the cheapest option at the time, although I have since been offered a 9a motor that would be the real deal

[vag_nutter]

I have a heat shield on the exhaust manifold but still gets really hot, not a great setup really, but the cheapest option at the time, although I have since been offered a 9a motor that would be the real deal

9a on carbs would be wicked

[Mk1Golf]

I am really tempted, but cash may be the deciding factor and i am not sure if it will go straight in on the original mounts.

Maybe I will buy it and save it for a later date.