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SU Fuelpump

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robolab

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Innerhalb der Komplettrestauration möchte ich bei meinem MKIII BJ8, Baujahr 1966, die kontaktbehaftete SU-Benzinpumpe gegen eine neue kontaktlose elektronische Pumpe tauschen.
Da ich bei meiner alten Pumpe den Typ nicht identifizieren kann und auch in der Serviceanleitung nur die alte Bezeichnung AUF 301 zu finden ist, weiß ich nicht, welches der richtige elektronische Ersatztyp bei BURLEN ist. Ich finde dort nicht genügend Hinweise auf den entsprechenden Typ (Ausgangsdruck,Volumen/h, Bauform). Außerdem habe ich vor die Polarität des Fahrzeugs auf Minus an Masse zu ändern.

Bevor ich mit Burlen telefonischen Kontakt aufnehme, kann mir jemand einen Insidertip geben, ob und welches Modell ich dort bestellen sollte?

Besten Dank im voraus
 
Now in English!

Within the complete restoration I would like to exchange the contact-type SU fuel pump for a new contactless electronic pump on my MKIII BJ8, built in 1966.
I can not identify the type of my old pump and in the service manual i only found the old designation AUF 301, I do not know which is the correct type for electronic spare at Burlen. I cannot find there enough evidence of the appropriate type (outlet pressure, volume / h, design). I also plan to change the polarity of the vehicle to negative ground.

Before I will call Burlen, has anyone a Insidertip , whether and what model should I order?

Thank you in advance
 
Thanks for the answer,

AZX1308EN seems to be the appropriate electronic fuel pump, I got the same answer from Burlen. But I'm not sure whether the mechanical pump fail less often. What experiences do Austin Healey driver have with the electronic SU fuel pump or the mechanical SU fuel pump.
 
robolab said:
...What experiences do Austin Healey driver have with the electronic SU fuel pump or the mechanical SU fuel pump.
Click to expand...

Way, way too much. I've probably bought a half-dozen SU pumps for my BJ8, both electronic and points, and changed pumps on the side of the road at least a half-dozen times. The points pumps are robust but require points cleaning and adjustment every few thousand miles--Norman Nock said it was a routine service procedure back in the day--and the points will need replacing eventually (probably around 10K miles, maybe more). In theory, the electronic pumps should go forever, but the diaphragm can harden with time and other glitches can claim them too. The advantage of the points pumps is you can change the points in a hotel room if you have to, when an electronic pump fails that's the end of the story. But, the points pumps have a 'shelf life' because the tungsten points will eventually oxidize and the pump won't, well, pump (hence the service). Note also there have been problems with aftermarket points being made of defective materials.

Bottom line: carry a spare. Install an electronic pump and carry a points pump as a spare, or vice versa, or use two of the same kind.

Did I mention carry a spare?
 
I put a Facet electronic pump in my 100 in 1981. I bought a spare in 2010 just in case. Never used it. The Facet is nowhere near being an original replacement but it sure is reliable! And cheap.
 
I replaced the original points pump on my 1960 BT7 in 1999 only because I wanted to go to negative ground. It was still working perfectly and in the 34 years I owned the car to that point, I never serviced the unit or replaced the points. At the time, it had around 130,000 miles. In a way I wish I had kept it on the car just to see how many years it would have lasted. My "new" negative ground points units has lasted 15 years so far without service or an issue. I guess I'm just lucky.
BTW, these SU pumps fail mainly because most people say they are LUCAS pumps and we all know how unreliable Lucas electrics are......
 
But I'm not sure whether the mechanical pump fail less often.

It is well known in the electronic industry that electronic switching devices are far more reliable than electromechanical ones. I have been running electronic fuel pumps for over 20 years without a failure.
 
Robolab,

Get whichever pump you want, but also get a Faucet electronic pump and put together a little "quick install" kit. In addition to the pump you will need wire with pre-made connections, a short piece of rubber hose and two hose clamps. Pre make the wires by measuring the distance to the fuse block and cutting the wires to the required length. Then install the correct connectors (female) to both ends of the wire. You Can install it in an emergency situation by disconnecting the rubber line at the carburetors and plunging the line into the Faucet pump. Then use a small piece of rubber fuel line to connect the outlet end of the Faucet pump to the carbs. Connect one of the wires to the fuse block and the other to ground. For safety reasons you should also make a small bracket to anchor the pump to the car rather than let it hang by the fuel line. Put all the parts in a small box and you have your back-up plan. It can be installed without having to crawl under the car on the side of the road.
 
Hi All,

For the last 50+ years, I have had 2 fuel pumps in my BJ8P1 and the original was only replaced (running perfectly) because of its age. After replacing the points, my first was installed in a friends BT and is still running perfectly today.

So what caused the points to burn or the electronics to fail. It turns out that many of us were under the misconception that since power to the pump usually ranged between 12 and 15 volts, this was the range of power fed across the points or to the electronic triggering components. As it turned out, since a coil is involved in the pump as an active component, similar to the ignition points and coil, several hundred volts are being passed across the points. As a result of these fluctuating levels of high voltage fed across the points or into the electronic triggering circuits, pump failure is only a matter of time and is usually unpredictable.

Over the years, experts like Dave DuBois (https://homepages.donobi.net/sufuelpumps/) had initially proposed the installation of a transistor to reduce the power that passes across the triggering points. As one that followed Dave's suggestion, I installed the transistor and benefited from reducing power across the points for the first year (I thought). However, this modification proved to be a failure (as Dave would agree) as, although it did substantially reduce power across the points, this reduction proved too low to burn off the oxidation that forms on tungsten points when idle and resulted in pump failure.

TVS%u00252520Electronic%u00252520Component.jpgSU%u00252520TVS%u00252520Installation.jpg
However, Dave's approach was not incorrect and a few years back, a diode was introduced called a Transient-Voltage Suppression (TVS) diodes that was designed to protect sensitive electronics from power spikes. This $1.50 component, when installed across the points, would shunt off flash voltage and maintain operation within a power range that would eliminate point burn but allow sufficient voltage to burn off oxidation. As a result of installing this component and an in-line power feed fuse, I expect my points pump to last until the diaphragm disintegrates (maybe another 30 years).

My suggestion is to keep the points and install a TVS diode.

Good luck,
Ray (64BJ8P1)

 
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