[Healeys] Negative ground SU fuel pump question

[Bob Haskell]

Kees,

What's flower paper?

Cheers,

Bob Haskell
Austin Healey 3000 BN7/BT7 registrar

On 5/10/21 11:48 AM, Kees Oudesluijs via Healeys wrote:
> Richard,
>
> Rebuilding SU-pumps is therapeutic and satisfying. I started years ago 
> after I retired. I still discover new things about them and keep 
> developing the technique and methods.
> I always prefer to keep the 3-layer diaphragm as it is far superior to 
> the later 2 or even single layer ones. As long as all three layers are 
> intact, reasonably supple, not cracked and can be (very carefully) 
> separated from each other without damage they are usually OK. When 
> cleaned (brake cleaner) and dried I dust them with a little talcum 
> powder to prevent them from sticking in the future and keep the rubber 
> in good condition. In the past I used some rubber grease. I still have 
> perfect original diaphragms from pumps that were fitted in the '50's. 
> One thing which is important is to take care with the Bakelite bridge. 
> Do not overtighten the fixing screws as the Bakelite is rather brittle 
> and cracks easily. However the plus side is that Bakelite can be 
> glued, and if bits are missing reconstructed, very well using araldite 
> or any other suitable epoxy glue. Same for the cap. It will leave a 
> very strong and lasting repair.
> Points are usually fit for sanding the worst pitting followed by 
> polishing them with flower paper. Old point may be preferable to new 
> points, the old ones are probably a better quality. They hardly wear.
> The main reason the SU-pumps are giving up is lack of use as electric 
> corrosion between the points will stop them working. I have done more 
> than 160.000miles in my first Jensen-Healey and never had one problem 
> with the fuel pump. Even after I laid up the car for about 10 years it 
> would still pump the fuel on my yearly start up of the engine. After 
> that it was left to its own devices and when I took it out in 2008 to 
> fit in my present J-H it failed! I took it apart, cleaned, inspected 
> it, polished the points and rebuild it with all its original 
> components bar the seals for fuel hose connectors. It has been working 
> flawlessly ever since and that was needed was a cleaning of the 
> points. Earlier I replaced the capacitor with a transil 
> (bi-directional Zener diode), 1.5 KE18CA. I now keep the capacitor and 
> fit the transil in parallel with it. It will decrease sparking 
> tremendously.
> In very old pumps single instead of double points are fitted and often 
> no capacitor is fitted at all from the factory. When rebuilding these 
> units I always fit a transil with or without a capacitor to protect 
> the points.
> If you want to carry a spare fuel pump, do not use an SU-pump. The 
> points will corrode in the boot after some time and it will fail you 
> when you need it. Better to get one of those $15 simple Facet fuel 
> pumps. They are crude, make a lot of noise but will get you home.
> Cheers,
> Kees
>
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