Swirl pots?

[TomLS]

Hi guys,
I guess this goes in here...
I'm thinking about replacing the high-level S.U fuel pump, with a constant pressure electric pump and a swirl-pot with a return to the fuel tank, which I can mount on the near-side tie bar.
I'm hoping to reduce the temperature build-up of the fuel to avoid vaporisation in the summer by:
a) providing continuous fuel flow, returning the surplus to the tank,
b) moving the fuel system low down and close to a fresh air supply.

I believe the S.U carbs require about 4psi of pressure, so does anyone know where I can get hold of a suitable small swirl pot?

I've seen a few on ebay but I'm looking for 50-100ml for about a tenner not 1-2l @ £50+

Thanks in advance,
Tom.

[bmcecosse]

There really is no need to go to all that trouble. Either convert to the mechanical pump (as used by Minis since ~ 1980) or simply mount the existing SU pump low down in the engine bay so it has a 'flooded suction'. You will have no further problems with the 'vapours'........

[TomLS]

Excellent idea!
How will the S.U pump deal with water spray?
If it's on the tie bar (seems the easiest place to mount it to me) it might be subject to considerably more spray from the road.
I guess I could mount it in its original orientation and use the vertical bracket I would have to fit as a water shield. I could also mount it partially behind the engine mount for additional protection.

One last thing - do I re-bend the original metal fuel hose, cut it before it turns vertical and jubilee a rubber hose in place, or replace the whole thing with a custom copper line?
My intention is to only change things in such a way that it can be easily reverted to its original layout for future sale purposes / my own guilty conscience!

[bmcecosse]

I assume you mean 'tie-plate' and not tie-bar........ Wouldn't worry too much about water spray - it should have a rubber band seal around the join of cap to body. If not - wrap with good tape! I suspect the original pipe will kink (or snap) if you try to straighten it out.

[mike.perry]

Does your car actually suffer from fuel vaporisation or are you just anticipating it?
The Series MM can suffer from vapourisation but that is because the fuel pipe is routed next to the exhaust manifold, there is no insulating spacer between the carb and manifold on the early engines and the float chamber is at the back of the carb. With the fuel line insulated or moved, a spacer between the carb and manifold and the float chambr moved to the front of the carb there is no need to move the pump or fit a return flow system

[TomLS]

Yes I did mean tie-plate . Bit of a newbie so still getting my head around all the terminology

Mike - I was told by someone at Charles Wares (make your own decisions) that I could have problems in the summer. The pump does feel awfully warm after a 2hr+ journey when its in the 20's outside. Its mainly anticipation. Mine is a 1970 Traveller and has the insulating spacer plate and the float at the front, but the pipework still runs within 2" of the exhaust downpipe, and it just generally seems a daft place for the pump! Plus I find the incessant ticking noises it makes rather tiresome, so would like it off the bulkhead really.
If I can get used to the ticking, I might dig out a sheet of scrap ally plate and some brake pipe clips and attach them as a shield where it passes the manifold, but the pump will still get hot.
My main reasoning for the move is to make the vehicle as reliable as possible without changing too much, its all very well carrying a spare (which I have) but I'd just rather not have to use it.

Tom.

[bmcecosse]

Only a relatively few cars ever suffer from the 'vapours' - I suspect probably due to short-stroking pumps where the points throw-over is not set correctly, and is certainly made worse by fitting a completely unnecessary fuel filter in the pipe from tank to pump!!

[mike.perry]

"Someone at Charles Wares" says quite a few things which may or may not be 100%.
It seems a lot of work for something which is not known to be a problem in this climate. As I said it is a well known problem with the side valve Minors and there are documented cures. The fuel pipe in the Series MM is within 1/2 inch of the exhaust