|Original SU High Capacity (Type LCS) pump - dirty and dead|
- The pipe work and unions would need some surgery with naff looking bits of rubber hose and clips.
- There is something reassuring about the click - click - click of an SU fuel pump.
- Depending upon the precise volume, tone and frequency of the "click" a whole range of fuel line faults can be diagnosed.
- The critical path / weakness, the points can now be replaced with a solid state upgrade kit. The downside to this is that you will no longer have the satisfaction of hearing the result of a good whack.
- It is still possible to telephone Burlen, the main UK supplier of parts and have a proper technical conversation with a knowledgeable human being.
- I think concours judges should ask for the ignition to be turned on and then deduct a few points for silence or some other inappropriate noise.
|Fully dismantled - note 11 brass spherical rollers. Also note |
the amount of very fine black muck on the inlet cover plate
compared to the relatively clean outlet side cover plate
|Diaphragm / Bronze rod, brass spherical rollers and return spring|
|For future reference|
A known working magnetic coil measures around 4 ohms
The service kit when it arrives is inspected and I find the bronze rod attached to the diaphragm is around half an inch shorter than the original. It transpires that this version of pump has a long and short body. More return postage costs! Also, the kit contains a new rocker / point assembly which will not be required.
|Ready for re-assembly. Parts on the bottom row are not required|
The diaphragm assembly is held central in it's housing by 11 (odd number ?) spherical rollers (thick brass washers) which appear to be unworn. These are reluctantly replaced by the 5 x figure of eight nylon items supplied in the service kit (see the above picture). There's probably a good reason for this, but I would be interested to know the thinking behind it. Also one of the two thin brass discs in the non return valve assembly is replaced with a plastic disc. It takes a phone call to Burlen to discover which one (its the top one - apparently ?) again - Why
Fitting the five nylon bits around the diaphragm was fiddly but otherwise, re-assembly was fairly straightforward.
The conversion to solid state was also quite easy and interesting. An aluminium machined bit (note - the term "bit" is used as a generic term for nondescript items) containing a small magnet is screwed onto the end of the bronze rod in place of the rocker / points assembly.
|Electronic conversion kit fitted. Aluminium magnet "carrier"|
in centre, screwed onto end of bronze rod.
The magnet influences a Hall effect transistor on the PCB which conducts, energising the coil which moves the brass rod and magnet upwards. Once out of the "influence zone" of the Hall effect, conduction stops, and helped by a big spring, the rod returns to its original position and the whole sequence starts again. On the pull stroke, fuel is sucked from the tank into a holding chamber and on the return stroke it is sent on it's way to the carburettors. This is probably an over simplification of the workings, but I think in principle, it's about right. One thing I have learned, is that the distinct clicking noise is not from the points as I had always imagined, but from the diaphragm centre hitting the body on the pull stroke.
|Re-built pump - total cost of parts including electronic conversion|
kit and set of new cheese head screws £110.05 plus carriage.
Around the same price of a Facet kit.
May 7th, Bank Holiday Monday in the UK saw a few JDC Area 11 members congregate at Croft circuit for a Track Day. Normally restricted to 88dB maximum (Normal car exhaust level) this was unusually a 105dB day which brought all manner of mad machinery out to play. My XK140 registered 98dB which I find hard to believe, but was assured that the meter had been calibrated that very morning.
|Line up of Jags at Croft. There was also a full race spec D type|
replica, but owner took it home and came back in the 120 OTS
Wife Angie's just gone on holiday to Spain, which should mean I'll have a little more to show than a re-built fuel pump in the the next fortnight.
Next Post - Beginning of June