My response sent Friday hasn’t shown up, perhaps it was too long and got
bounced or something, anyway here’s a short version. For the full
instructions go back in the archives to my January 2003 posting. I thought
it was in the library but I couldn’t find it.
I haven’t heard of Haring, but I have one I pulled from a '59 Mark 1 which
has stamped steel end covers rather than the usual cast aluminum. I always
assumed it was a later version SU.
This is instructions for rebuilding the SU fuel pump and adding a
transistor and a diode to make it last longer. The original plan was
published by the Classic Jaguar Association in July '89 and Jan '90. They
got it from the Vintage MG folks. A version by David Dubois is posted in the
XK library. Alastair Reynolds of the Jag list has suggested also adding a
resistor and capacitor, which I have included below.
My photos are in the jag-lovers photo album under miscellaneous restoration.
Here is the Dubois positive ground version:
Here is the Dubois negative ground version:
Here are my photos:
Going from the DuBois version, the Reynolds version eliminates the 25 ohm
resistor and joins the points blade directly to the transistor base pin (my
yellow wire). A 1000 ohm resistor connects the transistor base pin to the
battery hot terminal (the big brass main connection stud). Then a 100 ohm
resistor and a 0.1 microfarad capacitor are joined in series and make a
connection between the transistor base and ground. In my picture they are
between the points blade mounting screw (connected to the transistor base
pin by the yellow wire) and the transistor mounting tab (collector &
ground). The green wire is my extension of the wire from the coil that was
Rob Reilly - XK120 FHC, Mark V saloon, XJ12L S2, all with converted pumps