[Healeys] S U fuel pump
bspidell at comcast.net
Tue Oct 20 09:18:24 MDT 2020
The late Dave DuBois, who designed the transistor-switch fix, quit doing
the conversions when he found the reduced voltage cross the points
allowed them to oxidize. I tried the transil fix, but didn't get much
more longevity than a stock points setup with a diode; I do know some
have had better luck with them.
I have a points/diode pump in my BN2 that works well, but I only have a
few hundred miles in the car. I've lost track of what I've got in my BJ8.
On 10/19/2020 11:31 PM, Kees Oudesluijs via Healeys wrote:
> When rebuilding SU electrical fuel pumps I ad a transil (e.g.. 1.5
> KE18CA) over the points, parallel or in stead of the capacitor if
> fitted. This reduces the max voltage across the points to 18V instead
> of several hundreds when the contact is broken and the points spark.
> It is also important to clean and polish the points using flower paper
> (2-3000 grid), also when new!!
> A transil is more or less a bi-directional Zener diode. They cost next
> to nothing. I buy them in bulk and pay about $0,15 but when buying
> only one expect to pay between $1 and $5. Ebay is an excellent way to
> source transils (mainly from China).
> A transistor circuit similar to those used in early transistorised
> ignition systems does a similar job by limiting the current through
> the points
> Kees Oudesluijs
> Op 20-10-2020 om 07:50 schreef Ray Juncal via Healeys:
>> I'm rebuilding a couple of early S. U. fuel pumps for my 100. In
>> checking my reference files I came across an article from the MG club
>> about adding a transistor circuit to reduce the amps across the
>> points. That would keep the points from burning and extend the life
>> of the points. Has anyone on the list tried this? The author of the
>> article claims he has 20,000 miles on the conversion and new looking
>> contact points. Thoughts, comments, suggestions.....
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Healeys