VAPOUR LOCK 3000S
Discussion
Just drove 230 miles over the w/e in very hot weather and as i had once before BIG PROBLEMS VAPOUR LOCK.
When i opened the Bonnet i could see NO PETROL or very little in the glass dome of the Mechanical Fuel Pump.
Luckily i have also fitted an electric "Huco" Fuel Pump in the Fuel Line next to the Fuel Tank. Which i can switch on when the car starts to splutter.
If i don't stop the Engine and switch the Electric Pump on i can survive and keep driving.
BUT if i stop then HEAT SOAK sets in and there is no way i can restart the car. I need to let it cool for a good moment and vapourise the Mechanical Fuel Pump and vapourise the Carb. + keep Electric Fuel Pump switched on to circulate the Fuel.
There is a return from Carb to Fuel Tank.
Any ideas to fix the problem as it's a real pain in the butt.
Alan
When i opened the Bonnet i could see NO PETROL or very little in the glass dome of the Mechanical Fuel Pump.
Luckily i have also fitted an electric "Huco" Fuel Pump in the Fuel Line next to the Fuel Tank. Which i can switch on when the car starts to splutter.
If i don't stop the Engine and switch the Electric Pump on i can survive and keep driving.
BUT if i stop then HEAT SOAK sets in and there is no way i can restart the car. I need to let it cool for a good moment and vapourise the Mechanical Fuel Pump and vapourise the Carb. + keep Electric Fuel Pump switched on to circulate the Fuel.
There is a return from Carb to Fuel Tank.
Any ideas to fix the problem as it's a real pain in the butt.
Alan
It was about 30° C hot enough for me.
The "Huco" Fuel Pump i have fitted is what i bought from WebCon. These do not need a pressure regulator and are suited for Weber Carbs. In my imho better than Facet.
Anyway i have started my way to cure the problem:
1. I have fitted a new Fuel Supply from Petrol Tank in 8mm dia Kunifer pipe that runs along the outrigger on the Chassis in cool air. No preheating of Fuel Line running along the tunnel.
2. I have used what was the old supply pipe for the return from Carb to Tank.
I will try this and monitor the Fuel inside the glass bowl on the Mechanical Pump for air bubbles/airlock.
If still a problem i will bypass the Mechanical Fuel Pump and switch on the Electric Pump.
When i stop with a very hot Engine if there are restart problems that would be HEAT SOAK vapourising the Fuel in the Carb.
Maybe a Heatshield could be a solution sandwiched between the Carb Flange and the Inlet Manifold.
Alan
The "Huco" Fuel Pump i have fitted is what i bought from WebCon. These do not need a pressure regulator and are suited for Weber Carbs. In my imho better than Facet.
Anyway i have started my way to cure the problem:
1. I have fitted a new Fuel Supply from Petrol Tank in 8mm dia Kunifer pipe that runs along the outrigger on the Chassis in cool air. No preheating of Fuel Line running along the tunnel.
2. I have used what was the old supply pipe for the return from Carb to Tank.
I will try this and monitor the Fuel inside the glass bowl on the Mechanical Pump for air bubbles/airlock.
If still a problem i will bypass the Mechanical Fuel Pump and switch on the Electric Pump.
When i stop with a very hot Engine if there are restart problems that would be HEAT SOAK vapourising the Fuel in the Carb.
Maybe a Heatshield could be a solution sandwiched between the Carb Flange and the Inlet Manifold.
Alan
I see what you mean it's best to remove the Mechanical Fuel Pump from the circuit and just use the Electric Pump.
I just wondered if some of the problem was the Fuel Line running along the Tunnel not too far from the twin stainless steel Exhaust System.
I will bypass Mechanical Pump and test run just with Electric Pump.
Thanks for your help
Alan
I just wondered if some of the problem was the Fuel Line running along the Tunnel not too far from the twin stainless steel Exhaust System.
I will bypass Mechanical Pump and test run just with Electric Pump.
Thanks for your help
Alan
So to update what i have done.
1. Fitted new Fuel supply line with Kunifer pipe running along the outside of the Chassis nice and cool.
2. Used old supply line for return to Tank.
3. Fitted Huco Fuel Pump in the Boot Tank outlet. Supplied using Fused Relay. Switched + supply from Ignition + Warning Light. I can switch off Fuel Pump when Ignition is on if needed.
4. Bypassed Mechanical Fuel Pump but left in place for the moment.
Took the car for a run along the Brittany Coast and wow 100%.
The proof of the Pudding will be on Sunday when i do a tour with the local car club.
Alan
1. Fitted new Fuel supply line with Kunifer pipe running along the outside of the Chassis nice and cool.
2. Used old supply line for return to Tank.
3. Fitted Huco Fuel Pump in the Boot Tank outlet. Supplied using Fused Relay. Switched + supply from Ignition + Warning Light. I can switch off Fuel Pump when Ignition is on if needed.
4. Bypassed Mechanical Fuel Pump but left in place for the moment.
Took the car for a run along the Brittany Coast and wow 100%.
The proof of the Pudding will be on Sunday when i do a tour with the local car club.
Alan
I fitted a "Huco Pump" from "Eurocarb" and it is low pressure for Weber Carbs.
No Regulator required on low pressure model. They sell 2 different models 1 is to fit in Engine Bay or the other to fit next to the Fuel Tank.
I fitted on my 3000M the model for the Engine bay low pressure but fitted it next to the Fuel Tank in the cool and dry. It runs very well and not noisy. I put a glass cleanable filter between the Pump and the Fuel Tank. I added a return from the Carb to the Fuel Tank.
On my 3000S i fitted the other Huco model (slightly more pressure) to be fitted next to the Fuel Tank also in the cool and dry. I have not fitted a Regulator and no problems. There was already a Fuel return from Carb to Fuel Tank.
On both cars the Pumps are feed by Fused Relays and Isolator Switch with only a low current through the Ignition Switch.
I hope this helps Alan
No Regulator required on low pressure model. They sell 2 different models 1 is to fit in Engine Bay or the other to fit next to the Fuel Tank.
I fitted on my 3000M the model for the Engine bay low pressure but fitted it next to the Fuel Tank in the cool and dry. It runs very well and not noisy. I put a glass cleanable filter between the Pump and the Fuel Tank. I added a return from the Carb to the Fuel Tank.
On my 3000S i fitted the other Huco model (slightly more pressure) to be fitted next to the Fuel Tank also in the cool and dry. I have not fitted a Regulator and no problems. There was already a Fuel return from Carb to Fuel Tank.
On both cars the Pumps are feed by Fused Relays and Isolator Switch with only a low current through the Ignition Switch.
I hope this helps Alan
No not quite,
the Carb is being feed at the Pump pressure.
In the return Fuel Line where it is fitted to the Carb there is a restrictor inside.
When you fit the return line using a "T" Fuel Line connector it has a Restrictor inside it.
The part of the "T" with the restrictor is where you connect the return line.
The adding of a return line to Tank was a modification that TVR did to reduce Vapour Lock problems.
Here's a photo of my Huco Pump Installation
Alan
the Carb is being feed at the Pump pressure.
In the return Fuel Line where it is fitted to the Carb there is a restrictor inside.
When you fit the return line using a "T" Fuel Line connector it has a Restrictor inside it.
The part of the "T" with the restrictor is where you connect the return line.
The adding of a return line to Tank was a modification that TVR did to reduce Vapour Lock problems.
Here's a photo of my Huco Pump Installation
Alan
Edited by plasticpig72 on Wednesday 27th June 13:43
Have a look on the EuroCarb site.
It is also possible to use say a 120 Main jet for a Weber slide up inside the return.
The return lines were used with a Mechanical Fuel Pump which don't deliver much.
Maybe the higher pressure Pump 4.3 psi (hucopump fp03) is best when there is a return Fuel Line.
For sure when i bought my 3000M it had a "Facet Pump" which made a hell of a lot of noise. I think after a while it used to get very hot and cause vapour lock inside it's own body. Also there was not a Fuel return to Fuel Tank.
Alan
It is also possible to use say a 120 Main jet for a Weber slide up inside the return.
The return lines were used with a Mechanical Fuel Pump which don't deliver much.
Maybe the higher pressure Pump 4.3 psi (hucopump fp03) is best when there is a return Fuel Line.
For sure when i bought my 3000M it had a "Facet Pump" which made a hell of a lot of noise. I think after a while it used to get very hot and cause vapour lock inside it's own body. Also there was not a Fuel return to Fuel Tank.
Alan
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