Fuel pump gasket

[promotor]

Very detailed and helpful. Thank you. One more question, is it possible to change the spring and do you know of a supplier?

If you have a glass top pump it's easy. Not sure of supplies though as I've always used my own spares.

Replacing the spring in a modern replacement ? I'm sure it's possible but as you rightly hint that is if you can find a spring supplier.

[2cams70]

Measure the fuel pressure first to see what you have. Worry about the next step after you've got this information! You can buy fuel pressure gauges reasonably inexpensively.

[daverubberduck]

I now wish I had simply fitted a regulator like Eric in Burnley. With hindsight it would have been much easier. I now have to check if the glass top pump I bought and fitted is the right one. I bought it off SJ Sportscars so I've sent them the question. I may also try to measure the pressure.

[Craven]

If the modern pumps are made in the same way and you can find/modify a suitable spring it can be changed with the pump in place.
Ron.

[promotor]

I now wish I had simply fitted a regulator like Eric in Burnley. With hindsight it would have been much easier. I now have to check if the glass top pump I bought and fitted is the right one. I bought it off SJ Sportscars so I've sent them the question. I may also try to measure the pressure.

It might have been much easier but IMHO the glass top bowls are far superior to most solid top ones available today, and easy to service too. All's not lost!

[2cams70]

Agreed. The original AC fuel pumps are the best and are completely rebuildable. No need for a fuel pressure regulator with these. Better to use the correct spring than an add on regulator.

[alan.barker]

I never knew there are different spring pressures, it's news to me .
I would have thought with the Lotus having 2 webers that the flow rate is the important thing.
Webers don't like high pressure as far as i know.
Alan

[2cams70]

As far as flow rate is concerned the number or type of carburettors doesn't matter that much. HP is a bit of a guide however. The more HP your engine is producing the higher the flow rate you require. Fuel has a given energy content per kg. The more HP your engine is producing the more fuel (energy) it requires. It's a direct relationship.
Whereas the fuel pressure required depends largely on the needle/seat/float design of carburettor being used.

[alan.barker]

+1 yes the HP.
The Lotus has a lot more HP than the engine that was in the Cortina.
When the Twin cam is turning at 6000 rpm it needs a lot more flow than the Cortina 1200 or 1500 engine.
Alan

[2cams70]

It would be interesting to know what the limits of the AC glass bowl fuel pump are. It seem to be capable of flowing enough for the big valve engine (126 bhp). I think that's about it's limit though - unless anyone else knows of it's use on other make engines with higher HP. It might have an RPM limitation too. As far as I know any racing or moderately tuned engine goes electric pump.

[daverubberduck]

This is probably a dumb question, but how tight should the screw be that holds down the glass bowl? And what is to stop this coming loose with the vibration of the engine?

[promotor]

This is probably a dumb question, but how tight should the screw be that holds down the glass bowl? And what is to stop this coming loose with the vibration of the engine?

The rubber seal under the bowl bottom helps to load the screw as does the tension on the arms that stretch from under the screw down to the sides of the pump.

Fairly (finger) tight will be sufficient - don't over do it though as the threads are only small!

[daverubberduck]

OK, many thanks for the advice