Lotus Elan and Lotus Elan Plus 2 Forums

I wonder if the capacity of the fuel pump would draw fuel on a larger diameter feed pipe.

You mean that if the intake tube was too large, the pump might not function properly and generate the required output pressure/volume?

Craven wrote:I wonder if the capacity of the fuel pump would draw fuel on a larger diameter feed pipe.

The fuel pump is a diaphragm type positive displacement pump. The larger the diameter suction line, the longer it takes to fill the suction line and prime itself. It may be only a few seconds longer to prime, but as long as there are no vacuum leaks, it will prime. There is not any significant suction lift ~30cm to prevent priming from the pickup in the tank.

Perhaps there's the other answer to why the factory line was so small diameter (apart from the factory's assessment that it was large enough to supply the carbs and a 1558cc engine): reduced priming time.

Seems reasonable. Especially given the pump has no manual prime lever under it (I miss that).

Could be this is a(nother) reason not to "fix" things that aren't broken. Or, as Jim Hall says on Jay Leno videos, "the law of unintended consequences" . . .

Sea Ranch wrote:Okay, here goes . . .

Vince, nice idea about the copper olive. Where do you get such a thing?

Craven, that insert looks very trick. Where do you get such a thing? And thanks for sharing about your little chemistry experiment. Good to know.

Randy

Loads of them at the usual "auction" sites.
http://www.ebay.co.uk/itm/301998692226 or http://www.ebay.co.uk/itm/121299360929
Note the difference in colour.

Craven is spot on with the insert advice, essential with a soft walled pipe or it can simply crush and pull straight out.

You might consider using an isolator valve before the pump. Makes draining the tank easier / turn the fuel off to the drain the carbs / isolate a fuel leak etc Lots of reasons.

http://www.ebay.co.uk/itm/111642406930

Vince

For future reference Ray at RDEnterprises sells the correct olive & nut for 1/4" nylon fuel line, his part number is 026E0370Nut.

What can I use to connect the 1/4" (nominal 6mm) (O.D.) nylon pipe to 8mm (I.D.) rubber fuel pipe? Or even 6mm rubber pipe. I obviously cannot compression on the rubber.

Somthing like 6mm compression one end and a male (horse tail) the other would be ideal.

I could push the nylon into 6mm OD rubber and convert from there but it seems a bit of a bodge.