Yesterday I participated with my New DHC (the blue one) in a rallye in Switzerland. By chance probably the only other New DHC run in Switzerland (the yellow one) showed up and parked next to mine.
During the rallye, when the engine was hot, I had some problems with starting the car and had to run it with a higher throttle than usual to prevent the engine from stopping at low revs e.g. around round-abouts. It was a very hot day (30° Celsius) and the engine got very hot although not over heating.
What do you think? Fuel vaporisation? Or what else could it be?
Every advice is welcome
Kind regards
Beat
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Always look at "ACTIVE TOPICS" to see all posts in date & time order as they are sometimes moved; or look at "Your Posts".
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2 New DHC in Switzerland - fuel vaporisation?
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Beat Weibel
- Posts: 185
- Joined: Sat Feb 27, 2016 4:13 pm
- Location: Munich
2 New DHC in Switzerland - fuel vaporisation?
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Re: 2 New DHC in Switzerland - fuel vaporisation?
Hi Beat
When your car was in England I saw it and the fuel pipe went from the pump to the carburettors in front of the thermostat housing. Originally it went behind this housing and there is a groove for the pipe to fit there. However I think many Conquests, including my NDHC have had the pipe put in front of the thermostat housing to reduce the heat going into the fuel pipe. I have also heard of people putting insulation around there. If the pipe has been moved to the "correct" position it may be worth moving it back.
I ran my car about 300 miles last weekend but it wasn't as hot in England. I nearly had problems with fuel supply on the way back. I found this was due to the petrol cap sealing against the rubber grommet and causing a vacuum to build up in the tank. You may remember we have both replaced that grommet recently. The car felt a bit hesitant over the last few miles going home. When I git home I removed the cap and there was a large sucking in of air as the tank returned to its normal shape! I have been having problems with fuel escaping from the cap, I now seem to have the reverse problem!
Best wishes tracking down the problem, I think fuel vaporisation is a possibility but look for other causes such as poor flow through the pipes (they can clog up, especially the reserve pipe - I had to clear mine out when I removed the tank).
Mike
When your car was in England I saw it and the fuel pipe went from the pump to the carburettors in front of the thermostat housing. Originally it went behind this housing and there is a groove for the pipe to fit there. However I think many Conquests, including my NDHC have had the pipe put in front of the thermostat housing to reduce the heat going into the fuel pipe. I have also heard of people putting insulation around there. If the pipe has been moved to the "correct" position it may be worth moving it back.
I ran my car about 300 miles last weekend but it wasn't as hot in England. I nearly had problems with fuel supply on the way back. I found this was due to the petrol cap sealing against the rubber grommet and causing a vacuum to build up in the tank. You may remember we have both replaced that grommet recently. The car felt a bit hesitant over the last few miles going home. When I git home I removed the cap and there was a large sucking in of air as the tank returned to its normal shape! I have been having problems with fuel escaping from the cap, I now seem to have the reverse problem!
Best wishes tracking down the problem, I think fuel vaporisation is a possibility but look for other causes such as poor flow through the pipes (they can clog up, especially the reserve pipe - I had to clear mine out when I removed the tank).
Mike
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theoldman
- Extremely Wise Man
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- Location: Bacton on Sea, Norfolk UK
Re: 2 New DHC in Switzerland - fuel vaporisation?
Beat,
Hot starting will be helped by changing the plugs to NGK BP6ES.
Cheers
Neil
Hot starting will be helped by changing the plugs to NGK BP6ES.
Cheers
Neil
Normal for Norfolk
Re: 2 New DHC in Switzerland - fuel vaporisation?
Hello Beat,
the boiling range of petrol is between 25°C .... 215°C. The petrol pipe of your NDHC is fixed directly behind the header tank of the radiator. The header tank contains the warmest / hottest water of the radiator-system as a result of thermal lift. So when you're driving in hot weather as you did, the temperature in the header tank can reach 100°C. While the radiator-system is under pressure there's no boiling cooling water at 100°C. The header tank is made of metal so you have a radiation next way to the petroltube and vaporation of the petrol is the consequence.
When driving with low revs the flow in the petrol tube is slow too and instead of compltetely liquid petrol only vaporized petrol is reaching the carb and the engine is running badly.
Kind regards
Rolf B.
the boiling range of petrol is between 25°C .... 215°C. The petrol pipe of your NDHC is fixed directly behind the header tank of the radiator. The header tank contains the warmest / hottest water of the radiator-system as a result of thermal lift. So when you're driving in hot weather as you did, the temperature in the header tank can reach 100°C. While the radiator-system is under pressure there's no boiling cooling water at 100°C. The header tank is made of metal so you have a radiation next way to the petroltube and vaporation of the petrol is the consequence.
When driving with low revs the flow in the petrol tube is slow too and instead of compltetely liquid petrol only vaporized petrol is reaching the carb and the engine is running badly.
Kind regards
Rolf B.
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Beat Weibel
- Posts: 185
- Joined: Sat Feb 27, 2016 4:13 pm
- Location: Munich
Re: 2 New DHC in Switzerland - fuel vaporisation?
Thanks for your advice. I will check the fuel pipe and the plugs.
Kind regards
Beat
Kind regards
Beat