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MG MGA - fuel evaporation

Hi , like many I suffer from poor starting and running when restarting from hot due to the front fuel bowl getting almost too hot to touch leading to fuel evaporation until the fuel flowing again cools thingsdown, I think I may have solved the problem by making a jacket for the front bowl out of some, very expensive, heat insulation stuff sold to cover firewalls etc, since doing it don't seem to have suffered the same problem

regards gordon
g c pugh

I would appreciate a photo Gordon, and a better description of the insulating material, if that is possible. In Aus. we always have fuel trouble when the summer temperature hits 40oC.
Barry
BM Gannon

Hi Barry, try this as a link, I don;t know if you can get the same stuff in Aus. http://www.holden.co.uk/productSearch.asp?keyword=insulation&hPartNumber=&lPartNumber=&pageno=2


regards gordon
g c pugh

sorry part no 091.445



gordon
g c pugh

Thanks Gordon. I have used a similar product over the transmission tunnel and under the floor carpet on exhaust side. Just did not think of it for the carbs. Thanks for the tip, I will give it a try next summer.
Barry
BM Gannon

Hi Barry , I simply wrapped it around the bowl leaving enough hanging below that I could fold up to cover the bottom of the bowl as well and secured it all to the bowl using double sided tape, very Blue Peter,
it only seems to be the front carb that gets so hot, it seems to have helped at the moment the car starts hot without the usual farting around that it usually does.


gordon
g c pugh

Just putting my lateral thinking hat on again. I sometimes wonder if these carb overheating problems have are a spin-off from incorrect aftermarket radiators. i.e. poor airflow through the radiator core. I am surprised that Gordon down in wet miserable Cornwall has fuel evaporation problems. I have an MGB expansion tank sitting right in front of my front carb, yet never have any such problems.

Steve
Steve Gyles

Hi Steve, wet and miserable is too right at the moment, I wonder myself where all the heat comes from it seems to happen after the car is switched off and left and a I sais it gets almost too hot to touch perhaps the heat from the rad helps to cook it as well, I,ve had 4 or 5 MGA's over the years and never had the problem before and some of those were pretty rough, I am running a 1950 cc engine so perhaps this is also some of the problem,


gordon
g c pugh

Gordon

Add a supercharger... (yes I am serious).

It locates the carb to the back of the engine bay, so it stays cool.

It also makes the car run cooler (about 20 degrees on my car).

It also has all the power and torque advantages of a SC - should be pretty amazing on a 1950 engine.
dominic clancy

Hi Dom. I still have drum brakes all round it's pretty hairy at times as it is lol


gordon
g c pugh

Don't even want to START thinking about that....
dominic clancy

Hi Dom I tend to leave a lot of room between me and the car in front lol

gordon
g c pugh

I think that the fuel we are getting now has a lower boiling point than the fuel of 40 years ago. That would be even worse with fuel that has alcohol in it. All of the modern fuel systems have a bypass fuel system that circulates back to the tank. This allows cooler fuel to be constantly fed to the engine compartment. If you could think of a way to do this to a MGA, when you turned the key on cool fuel would be fed to the carburators solving the problem.
Ed Bell

I know how to install fuel re-circulation on the MGA, quite simple. The primary ingredient is adding a fuel return line back to the tank.

Procure a duplicate of the 2-way banjo fitting from the rear carburetor and install it on the front carb to provide an extra fuel port there. Alternate is to drill and tap the head of the front banjo bolt to provide the extra port. Install a 1 to 2 psi in-line pressure relief valve at that point, and connect the return line.

The fuel pump must be able to generate more pressure than the relief valve setting, but the carbs should operate well with minimum 1 psi at the output end of the line (equivalent to a 2-foot gravity head).

As an additional measure, I have toyed with the idea of wrapping 1/4-inch copper tubing around the float chambers as part of the return line to provide additional cooling to the float chambers. The fuel tank will serve effectively as a very large heat sink and radiator.

Barney Gaylord

This thread was discussed between 02/06/2007 and 04/06/2007

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