Routing fuel lines on a GT6

[Karl R GT6]

Hi.  After a near miss this week with perished fuel lines, I'm replacing all my fuel pipes with new R9 type.  The current installation routes the pipe around the front of the engine to the front carb and then onto the second carb.

 

My question:  if I swap over the float chamber tops, can I route the fuel lines to the rear carb first so I can route fuel line around the rear of the engine? 

 

To me this looks straightforward, but want to pick your collective brains and knowledge before I do something obviously daft.   Thanks. 

[dougbgt6]

People do run the fuel line round the back, but not really necessary, why do you want to? 

Doug

[Karl R GT6]

43 minutes ago, dougbgt6 said:

why do you want to?

Because where it currently runs around the front, it's really close the fan belt, and it runs between hot pipes from engine to rad, so is subject to more heat. 

 

[NonMember]

26 minutes ago, Karl R GT6 said:

it runs between hot pipes from engine to rad, so is subject to more heat.

No. Round the front it's exposed to some residual cold air, too. Routing round the back, where there's no air flow but still plenty of engine heat, doesn't help.

With SUs (I see you've converted yours so all bets are off anyway) it is possible to swap round float chamber tops and do what you want. I've done so with my Spitfire, but that has an electric fuel pump so the routing stays away from the engine to keep it cooler.

[dougbgt6]

I replaced ALL the metal work between pump and carb pipework with R9. This reduces the incidence of the dread rubber slivers caused by pushing metal pipe into rubber tube. The tube runs in the gap between rocker cover and thermostat housing. R9 hose is a better insulator than metal so no heat problems.

Doug

[Paul H]

Just make sure your R9 is not from EBay there’s a lot of fake on there . Gates Barricade is the best from Moss or the Club Shop 

Paul 

[Nick Jones]

1 hour ago, NonMember said:

No. Round the front it's exposed to some residual cold air, too. Routing round the back, where there's no air flow but still plenty of engine heat, doesn't help.

With SUs (I see you've converted yours so all bets are off anyway) it is possible to swap round float chamber tops and do what you want. I've done so with my Spitfire, but that has an electric fuel pump so the routing stays away from the engine to keep it cooler.

Really can’t agree with this. The original pipe run seems calculated to add as much heat to the fuel as possible with it in very close proximity with, even strapped to, big chunks of heated cast iron at 85C. Any airflow has mostly already passed through the rad core. 
 

Daftly enough, I still use this route as the return leg of my EFI fuel supply system and after a long run the fuel temperature in the tank can get up into mid 40s in spite of the potential cooling from two-way lines under the car.

So, fo my GT6, with the express aim of heading off fuel vapourisation problems I ditched the mechanical pump and ran the fuel line around the back of the engine, on the bulkhead. The Stromberg link pipe was remade backwards and the fuel now comes from the back. Total pipe length is less than before and none of it is very near the engine - which surely has to be a win!

Interestingly enough, electric pump aside, this is the basic design used on the later 1500s, though the pipes do sit nearer the the engine.

So, to the OP, your plan gets my vote. The advice on the R9 pipe is spot on though. I use Cohline 2240 which is available from Glencoe, Merlin MS etc. Personally I prefer to hard-pipe as much as possible.

Nick

[Karl R GT6]

Thanks for the comments an advice.  I'm going to mock up routes when the new pipe arrives and see what looks best and keeps the pipes away from hot bits. 

[Dave the tram]

Bit late joining this thread but my gt6 has a metal fuel pipe all the way from the pump, around the front as described above and the only time the car had let me down in 15 years of use as regular transport was with fuel vapourisation a few years ago. To be fair this was after an hour in a motorway queue immediately after a long run on a very hot day.

insulated the pipes with foam pipe insulation (sold as ok at high-ish temperatures) and it’s been fine ever since. Last Friday did a 200 miles, mostly at 70mph, from North Derbyshire to Suffolk with no problems even though sunny and over 30 degrees on arrival. Seems like a simple solution. Fuel was cool, engine temp spot on, driver JUST ABOUT OK - windows shut, full blower through face vent! Aircon would have been nice but kept telling myself it’s how we used to do it.

Dave

[dougbgt6]

Dave,

air con was offers as an option on Gt6 $370. Not many takers I think, bit expensive compared to overdrive at $121. But they’re out there! The clue is in the $, USA only?

Doug