AC fuel pump diaphragms

[andrew honychurch]

I am just refurbishing my AC fuel pump and even though its new, the diaphragm is not going to work for very long from past experiences of these items. Modern fuels with ethanol tends to dissolve the old material. I wonder if anyone has dealt with this problem other than by putting in an electric fuel pump. Is there anyone out there making new diaphragms? Given the tendency for Carriers to suffer with fuel vaporisation maybe an electric pump will be the best way forward. Any thoughts much appreciated.

[rob love]

Dealers of the antique parts have adjusted their new stock for the ethanol blends. Here, for instance, is a link to MAC auto's fuel pump, which states: "This pump is compatible with current E10 ETHANOL fuel blends".

http://macsautoparts.com/early-ford-...R3CHL1073533E/

Many of the dealers have adjusted their rebuild kits as well towards the new fuel blends.

[andrew honychurch]

Thanks Rob. Unfortunately this is not the fuel pump fitted to the T16 ( I mitted to mention my vehicle in the post) . I will check with one of the "new" V8 suppliers and ask whether they do a diaphragm for a T16 pump, it woudl certianly be the best way forward. I just wondered what everyone else does. Maybe there arent that many running Carriers on the forum!

It has certainly been my experience that old material will turn to goo pretty quickly once petrol hits it, and of course this coudl endanger the engine if the fuel drains down into the sump diluting the oil. So you have a double worry with old diaphragms ( nothing changes in life does it?)

[horsa]

Brian Asbury has rebuild kit rubber diaphrams for the T-16 fuel pump. I got one from him a few years ago when I was rebuilding the one for my carrier. It seemed to work OK with modern fuel but only time will tell as it sits exposed to the ethanol mixture.

Because of fuel/pressure issues I ended up hiding a remote modern electric fuel pump to ensure 3.5psi of fuel. It also prevents flooding when things are hot and you shut down the engine which would then have made it impossible to restart without sitting an hour. I'm still pushing fuel through the orignial fuel pump but am not using the lift rod on the engine which would pump the diaphram.

[andrew honychurch]

Interesting information thx David. I did much the same on my Stuart tank and replaced the original diaphragms with a simple neoprene gasket and then fitted an electric fuel pump instead. I am minded to go with the latter as another problem with modern fuels is the ammount of additives which seem to turn into gases and cause vapour locks. I have found on other vehicle having a modern higher pressure pump will help compress the gasses and allow fuel through when hot. I think a lot of modern systems get by this problem with having returns to the fuel tank from the carburettor. I did read your old post and you stated that there was a difference between the Carburettor pressure requirement and the fuel pump output. I can certainly see from the manual what the AC pump puts out from the manual but i have not found out any information on what the Holley carburettor is designed to accept. I am sure in the long run, the T16 will run better with a modern fuel pumping system in place.

EDIT...the point being that if one has too much pressure then presumably the carb will flood

[horsa]

A fuel return would have solved a lot of problems and ensured easy starting. But I couldn't think of a good way to hide it so settled for the electric fuel pump on its own.

On the pressure, seems like the original fuel pump is either 4 or 4.5 psi and the carb was 3.5 psi. Not a problem if everything was seating properly and the fuel pump wasn't actually putting out more pressure than it should. I never determined where my problem was coming from. Had lack of power trying to accelerate under a load when hot and it seemed to be flooding itself. The electric pump with pressure regulator solved everything which made up for my inability to resolve the mechanical problem properly.

[Marc van Aalderen]

Originally Posted by andrew honychurch

I am sure in the long run, the T16 will run better with a modern fuel pumping system in place.

Andrew,

Dirk Leegwater has NOS 6v fuel pumps. If you want I'll pick one up for you as you need the drive gear also. I'm going to Dirk in the next couple of weeks. Just let me know.

Cheers,
Marc