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MG TD TF 1500 - Relocating the carb to carb fuel line

AS noted in the "Classic Engines, Modern Fuel : The Problems, the Solutions
by Paul Ireland" book, the carb to carb fuel line was relocated from above the manifold to the air filter side to help prevent fuel boiling due to heat soak problems.
Just finished doing this on my TD.
Len Fanelli


Len Fanelli

Len. I would have thought that heat wrapping your headers would have had a more overall effect on heat.
Bruce Cunha

Must try that tomorrow. Have 2 driveable days coming up on Thursday and Friday. Today was the first one in January. finally got Lazarus out for his monthly run. Felt good, but started to rain just before getting back to the garage. Bud
Bud Krueger

Must try that tomorrow. Just looked at present setup. Something doesn't seem right with the present OEM setup with the stock air cleaner. Looks as if the horn gets in the way. I'll find out tomorrow.
Have 2 driveable days coming up on Thursday and Friday. Today was the first one in January.finally got Lazarus out for his monthly run. Felt good, but started to rain just before getting back to the garage. Bud
Bud Krueger

Triumph did it that way. I always hated it though, because it made working on the carbs a little harder. I don't think the fuel in that hose is really a hot spot anyway. The bottom of the fuel bowls and carb bodies seem to get a lot more heat. I suppose every little thing could add up though.
Steve Simmons

Have not had fuel vaporization problems with my TD but on other cars I have just covered the fuel hoses or metal pipe with a section of slit rubber hose such as heater hose or aquarium plastic hose. Perhaps a bit too dense to be a great insulator but better than nothing.
John Quilter (TD8986)

I agree with Steve on the carb bowls being a sensitive area for excess heat. I rotated mine on the TF out as far as possible plus installed one of Barrys heat shields and the problem went away. My problem was more heat soak than anything after shutting down for a short period on 90+ degree days.
PJ Jennings

With Manley Ford headers ceramic coated and NO insulator / spacer blocks I have had, almost. no heat soak issues except for 10 years ago in traffic with ambient temperature of 105-108 degrees. This summer on a warm but not hot day I did have an heat soak issue, on a hot restart, that lasted about 5 minutes in around town driving.
With Manley's intake / exhaust header the carburetors are farther away from the heat of the exhaust manifold.
With the extra length of the intake manifold there was no room for the thick TF spacer / insulator blocks and still be able to close the bonnet.
By the way Doug Pelton FTFU has 5 MM spacer insulator blocks for the stock TC /TD H! 1 1/4" carburetors, I may try these, enlarging them to 1 1/2".
Oh and Joe Curto has Float Bowl Koozies to insulate the float bowls.
Len Fanelli



Len Fanelli

I decided to stay with the original fuel routing because of Paul answer to my post in his forum.

"However, the good news. This is possible a good thing to happen. The Hot Restart Problem is caused by petrol boiling in the jet of the carburettor. If it boils BEFORE the float chamber, the vapour is released as the petrol enters the float chamber leaving only the higher boiling point components to enter the jet. These are less likely to boil in the jet and cause problems."

Laurent.
LC Laurent31

Like Len, I have had no vapor lock issues even with no special heat shielding. That includes temperatures around 115F. The type of fuel being used plays a big part as does engine tune. This is in a TC but there is little difference with the issue on TD.
Steve Simmons

Len,
I moved my fuel line way back and I don't know if it makes that much difference but I was then in Maine. Down here in Florida I can still have an issue if I stop after a good run and want to restart quickly. with temps over 90F
If I get a reluctant start, I just pull the choke to get over it.
I also have the spacers between the manifold and the carb bodies.





Rod Jones

This thread was discussed between 26/01/2021 and 31/01/2021

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