Constant flow fuel system setup?

[TomLS]

Hi all,
During a long trip to and from Staffordshire last weekend, I got stuck for about an hour in heavy traffic on a hot day (the M6 is awful!).
Although my main concern of boiling over didn't happen (she never even smelled hot), the fuel pump did start its old trick of ticking rapidly due to vapor lock, which forced me to start and stop the engine for about 30 mins to avoid it totally overheating!
I also had the steel fuel feed pipe under the bonnet covered by a heat shield.

As much as I'm attached to my moggy in original spec, My reason for buying her is that I wanted a classic car that was a real alternative to a modern car, and this issue negates this, so I'm going back to an earlier idea of fitting a constant flow fuel system, with a return line to the tank (along with an electric cooling fan)

What parts have people used to do this conversion? Do you use a pressure regulator valve, or a swirl-pot to regulate the fuel? I've recently heard that people are having problems with 'Facet' fuel pumps, and they are the only aftermarket pump I'm familiar with - what are the alternatives?

Cheers in advance
Tom.

[bmcecosse]

Just mount the pump low down in the engine bay - so it has 'flooded suction' from the tank - you don't need to go to all the fuss you are suggesting!

[TomLS]

Could fuel not still vaporize in the pipe between the pump and the carb? I had this problem between the swirl pot and carbs on my landy.

[IslipMinor]

I have a rear mounted Facet pump in the boot, so the fuel in the line to the carburettor is always under pressure. As an added precaution, the exposed tubing coming up from under the floor into the engine compartment has a length of split rubber hose round it to insulate it from the exhaust heat. The fuel pressure regulator/filter is mounted where the original SU pump was.

The reason for the Facet is to provide the level of fuel flow the engine needs, but has the advantage of needing to be rear mounted.

We were on the M25 around Heathrow a few years ago, when the temperature hit the magic 100°F and even in the slow/non-moving traffic for quite a while, the fuel flow never faltered. Again 3 years ago we were part of the Lord Mayor's Parade and progressed at walking pace or less for an hour or so - again never a hint of fuel problem.

[bmcecosse]

Fuel only evaporates in the 'suction' line - so eliminate the suction line by providing flooded suction. And yes- mount pump at rear if you wish, but it's more exposed to wet/mud/debris there. And ideally - you would need to swop to a 'pusher' pump - but in practice, the Minor pump works fine - at least low down at the front, it does!

[IslipMinor]

but it's more exposed to wet/mud/debris there

Yes, agreed, that is why I mounted the Facet in boot, down in the spare wheel compartment, on the LH side of the rear bulkhead. That way it keeps spotless!!

[bmcecosse]

Good plan!

[gatsby989]

but it's more exposed to wet/mud/debris there

Yes, agreed, that is why I mounted the Facet in boot, down in the spare wheel compartment, on the LH side of the rear bulkhead. That way it keeps spotless!!

I am just preparing to mount a facet pump at the rear of my moggy. I was going to mount it underneath the boot, but this sounds like a better idea. Couple dumb questions if you don't mind:
1. Is the fuel line steel? If so, will a plumber's tube cutter handle it?
2. How did you route the fuel line into the boot? Just drill a couple holes for flexible fuel hose? Grommets to keep them from being damaged?
3. Where did you route the wire for the pump? Under the carpet?

Thanks!

[IslipMinor]

The fuel line is cupro-nickel (Kunifer), but copper would do as well. I wanted to replace the fuel line, so I have extended it into the boot area using rubber grommets to protect it. I suppose you could use flexible hose and the existing line? To bend it I have a small tube bending tool that I use for brake lines, but it will do slightly larger tubing as well, but needs quite a bit of effort!!

The harness to the rear of the car is sheathed with a split plastic tube, so I ran the additional wire for the fuel pump inside that as well. No reason why it could not be run inside the car though.

[MarkyB]

Anyone making changes to the fuel system needs to bear in mind that ethanol is going to be added to petrol in greater quantities in the foreseeable future.
It's happening already in France and we were warned to avoid it as it is not compatible with some components in our systems.

[drivewasher]

Can someone explain this hot fuel pump milarkey to me please. Why does it happen the full details please.
Also if I were to modify to a rear pump, I would try and leave the visible parts as origonal IE The pump on side of battery box. I would leave all the pump and it's pipework in place, remove the valves from the old pump to allow an unrestricted flow of fuel through it then it would all look as if it hadn't been altered

[bmcecosse]

It's been covered many times - but basically - the fuel has to be sucked up by the high mounted fuel pump - this makes the fuel in the suction line more vulnerable to vapourisation in hot weather. Happens to some - never happens to others - probably made worse these days by the modern fuel make-up. Made worse by fitting fuel filter on the suction line! Sure fire fix is to provide the pump with flooded suction - either mount it low in the engine compartment, or use the mechanical pump fitted to all Austin versions, and all Minis from about 1978 onwards, or fit the pump low down at the rear of the car as discussed above.

[drivewasher]

My vans a 1971 Austin and it seems to be origonally set up with electric fuel pump. Do you thinkit should have a mechanical one? The plate by the camshaft is a "blank" pressing but it's NOT the origonal engine.

[bmcecosse]

Ok Ok - all Austins EXCEPT the Austin Minor Van - which wasn't really an Austin at all.... as I'm sure you know......

[drivewasher]

No I didn't know, so my van should be electric. There you go I just learned something!

Oh right! just got what you mean, it's only the badge and possibly the grille!