A little more cool air might help.

[Gareth]

The Roadster has been suffering from fuel evaporation when stuck in traffic so I thought this blower from an inboard engined boat may be the answer...
So today I've mounted the blower behind the front number plate and ducted it to underneath the carb.
Just need to go out and find some traffic and see if it works, shouldn't be too difficult!
Gareth.

[stevejgreen]

Re: A little more cool air might help.

Interesting idea. It should active something.
Some Marinas, were fitted with heat shields between the fuel pump and block. Not sure if a heat shield will work in the confines of a Roadster engine bay though, but worth a try. somewhere I have some drawings, I will try to look them out later.

[Gareth]

Re: A little more cool air might help.

Cheers Steve.
The idea is that as I go along, some cool air is scooped up towards the carb, and in traffic I can switch on the blower to cool things down a bit. Every little helps, as they say...
Quite chuffed at being able to hide the blower from sight and no holes needed to be drilled to mount it.
Gareth.

[stevejgreen]

Re: A little more cool air might help.

Can't find drawings, they will appear when I least expect it.
Meanwhile I have scanned my parts book that shows two alternative 'proper' heat shields for the fuel pump. here or there

One thing that the Parts book shows is two methods of mounting the pump, bolts or studs. In the confined of the Roadster engine bay, the use of studs is much more preferable as you can thread the gasket and insulator onto them and finally locate the fuel pump, compressing its lever against the cam as you go.

[b_caswell]

Re: A little more cool air might help.

My experience is with Triumph engines but the fuel pump is the same design. Installing an additional spacer/insulator moves the action of the cam away from the pump arm reducing its performance unless you use a pump application for the thicker insulator. The reverse also applies using a pump designed for the thick insulator without it will over stress the arm and it will snap(done it got the T shirt)

Another reason for the car suffering from( I assume) difficult re starting when hot is that the fuel pump is tired or damaged and stuggles to over come a vapour lock. I have come across a couple of cars both Marlins that had hair line cracks in the pump body which allowed drain back aswell as struggling to prime themselves again.

[Gareth]

Re: A little more cool air might help.

Thanks Steve.
Interesting Ben, I'll look into that.
Gareth.

[stevejgreen]

Re: A little more cool air might help.

My experience is with Triumph engines but the fuel pump is the same design. Installing an additional spacer/insulator moves the action of the cam away from the pump arm reducing its performance unless you use a pump application for the thicker insulator. The reverse also applies using a pump designed for the thick insulator without it will over stress the arm and it will snap(done it got the T shirt)

The parts list is quite clear, there is a different insulator with or without a heat shield, though there is no dimensional information, it would be understood that with a heat shield the insulator would be thinner. The drawing I am searching for shows just that.
It sounds a bit counter intuitive, thinning an insulator when fitting a heat shield, but I suppose the heat shield dose two jobs, protecting the pump from radiated heat and acting like a finned heat sink.

[stevejgreen]

Re: A little more cool air might help.

Previous link was for Mk2 Marinas, this is for Mk1 Marinas here or there Ihave not done a thorough parts comparison.

[davidmartin720]

Re: A little more cool air might help.

Interesting comments about fuel pumps on Triumph engines. I changed my fuel pump as I thought if it was the original, the petrol could end up in the engine oil as the diaphram looked brittle. This was the start of my problems, SU carb flooding, [good job I had put a Stainless steel shield to stop petrol from carb alighting on hot exhaust pipe] I changed the valve in the carb for a new one, then for a "Grosse" one, still with the same problem, I then fitted a petrol regulator which solved the problem. Or so I thought, is the arm in my petrol pump too close to the cam ????? How do you check. David.

[cameronfurnival]

Re: A little more cool air might help.

flooding SU carbs means the float isnt cutting the supply off. This can be because it has a hole in it and isnt rising properly, or the float needle isn't seating, I would try another needle valve and its brass jet together - the grosse types are better because they have flexible tips but they may not counter excessive wear or a chunk of crud wedged in tight. A fuel regulator is only really necessary if you have an electronic pump imho There are some good SU tune up bits and pieces in the workshop manuals section (or google for them).
I would doubt that the mechanical fuel pump would be pumping too hard (unless it was the wrong one fitted) and would spend my time on the carb bowl. Another cause of flooding is caused by air trapped in the float chamber. When fuel is fed into the float chamber it rises and the float shuts off the needle valve. If, however, the chamber air vent is blocked, the fuel rising compresses the air in the chamber and fuel is forced out of the jet at pump pressure.
There are several different methods of venting the float chamber, from a simple hole in the lid to overflow pipes, all of which can be blocked in various ways. If in doubt, loosen the fixing of the float lid just enough to allow air to escape and see if this cures the problem. If it does, then hunt down the blockage and remove.

[b_caswell]

Re: A little more cool air might help.

Interesting comments about fuel pumps on Triumph engines. I changed my fuel pump as I thought if it was the original, the petrol could end up in the engine oil as the diaphram looked brittle. This was the start of my problems, SU carb flooding, [good job I had put a Stainless steel shield to stop petrol from carb alighting on hot exhaust pipe] I changed the valve in the carb for a new one, then for a "Grosse" one, still with the same problem, I then fitted a petrol regulator which solved the problem. Or so I thought, is the arm in my petrol pump too close to the cam ????? How do you check. David.

If the pump was too close to the cam the arm will either bend or brake. The pump should provide 1½ to 2½ lbs per sq inch pressure, nothing more nothing less. Try running the car with the original pump to see if that overcomes the flooding. (shot in the dark really).

[stevejgreen]

Re: A little more cool air might help.

Fuels with a higher ethanol content may be more prone to vapour lock issues.
An article published in the Marina owners club magazine is here or there

[andyf]

Re: A little more cool air might help.

I noticed the other day when it was warm that my electric pump was noisier than usual and that the fuel was frothy in the filter as though it had a lot of air in it.