Fuel Pump Overheating So I've Moved It

[Simon Marks]

With the weather forecast for last Friday being for the hottest day of the year, I thought I'd take my Westfield Eleven to work (a 70-mile round trip) so that I could see how it behaved in hot conditions. The trip home was rather a disappointment. The air temperature was 28 degrees and, after six miles, the car stuttered, then stammered and cut out. The fuel pump (Facet solid state cube type) was tapping away but was very hot and the bowl on the Filter King was empty. I had taken a cold bottle of Highland Spring out of the office fridge before leaving the office so I squirted a dose of this over the fuel pump. With that done and the front clam secured, off we went again. In the next 35 miles (I had to go a longer way home to dodge a lot of standing traffic and use some 12-car road rally lanes that were congestion free), I had to repeat this exercise six times (I bought another 1.5l bottle of chilled water from a garage) - so that definitely was the problem!

I had sited the pump as suggested in the build manual but the under-bonnet temperature was obviously getting very high, exacerbated by the pump being at the top of the engine bay and, I am assuming that this was allowing the fuel to froth so that it would not pump, despite the tank being over half full at this stage.

In the Demon Tweeks catalogue, it says that this type of fuel plump should be mounted close to the fuel tanks, so I took the decision to remount it low down in the pontoon just in front of the fuel tank. Doing this was straightforward (particularly after having fitted an elbow outlet on the pump that directed the hose towards the existing hole in the wing), the most involved operation being to extend the wiring. I have left a plug/socket on the top off-side chassis rail (the original fuel pump location) so that I can isolate the pump if fiddling with the car. With the pump now being outside the engine bay and being lower should appreciably reduce the temperature of its operating environment.

The pump fired up straight away after I filled the tank and turned the key and it was noticeable that it was shifting fuel much quicker than before (when it seemed to be priming for a few seconds before the tapping note deepened). I need to pick up a couple of grommets to seal the old pump mounting bolt holes and wait for another hot day to test it thoroughly. I'll report back when I have done this.

Simon

[Splat]

Although my pump is the trad, cylindrical SU unit, converted to pointlessness (!), its mounted in just that position and I've never experienced any problems with overheating (and I've driven my car in some HOT weather!). Hopefully you've cured it!

[Westfield 129]

78F here is, well, Tuesday. It's sort of that temp all year around, 'cept when it is hotter. MUCH hotter.
I always put the fuel pumps next to the fuel tank, as it is a cool area, and convenient should you ever need to replace the pump on the road (While those little Facets are reasonably reliable, I have had to replace one. I believe that their best attribute is that they are available at just about any auto parts store, and they are amall and cheap. Carrying a spare along is easy). Plenty of room by the tank, and little trouble to run a fuel line from the tank to the pump, and then acros the inside of the scuttle to the carburetors.

I have never had a proble with a fuel pump due to heat (icluding ambient of over 105F) in that position, and it is unlikely that you will.

Now, you may need a proper fuel pressure regulator now that you have the pump's full rated flow.

[Simon Marks]

Hi, Both,

Thanks for the replies. It looks like I have come to the right conclusion and taken the right action. I do have a spare Facet in the garage (it came with the remains of a rally car that I came by some years ago). I have fitted a Filter King so can adjust the pressure, should this be needed. I'll check.

Simon

[bobwhittaker]

CHINESE FACET :-

Available on ebay for the princely sum of £9.95 including VAT and postage .
I have one on the XI and only last week fitted one to my Rover V8 ( 3.5 litre )
engined scratch built HMW . It has never missed a beat since .

I wouldn't install those pumps where they have to suck the fuel up , always give
them a positive head .

[Simon Marks]

Hi, All,

I had the Eleven out today - to a Sunbeam Lotus Owners' Club meeting at Santa Pod. I was able to use the engine temperature gauge as a thermometer (as it never dropped below 32 degrees between 09.30hrs and 14.30hrs when the car was parked on grass). This is four degrees hotter than when it all went wrong a few weeks ago. On the 80 mile run home in such heat (via a friend's house near to Santa Pod), it never missed a beat.

I consider the problem sorted and personally add my recommendation that any new builders site their pumps in the pontoon close to and in front of the fuel tank.

Simon