I've been running a Pertronix Ignitor in my 1275 powered TA now for a couple
of years. I love this unit. It fits entirely within the distributor and only
has two wires emerging. Its been entirely reliable and its such a relief not
to have to worry about points and condensers and bushing wear. I had heard
that Martin Veem up in Napa, CA converted an XPAG distributor so I thought I'd
try it on my Arnolt.
I used a part number LU142, same as for the sprite/midget purchased from Skip
Kelsey. Skip has the best prices on these things. The LU142 is designed as a
bolt in replacement for the points on the 1275 distributor. Units are also
available for the MGB's also....I presume the MGA also.
The XPAG application presents some problems because there isn't enough
clearance for the magnetic rotor to clear the point plate. Proceed by
stripping off the points and condenser of your plate, I used a "Uni-bit" to
bore out the hole in the center of the plate so as to have clearance for the
magnetic rotor. You will find that the mag rotor will push down snugly on
your distributor shaft which is proper. However if the pickup unit were to be
mounted on the plate as normal, it fouls the high tension rotor and its too
high up for the magnets to trigger it. The trick is to mount the pickup in a
lower position.
I did this by hacksawing the squared and lowered part off the point plate.
The cut will intersect the bigger hole in the middle. Now drill a small hole
in the end of the pickup base that doesn't have a hole and drill two holes on
either side of the point plate. Arrange the holes so that you have about .040
clearance between the mag rotor and the pickup unit. You are going to use the
pick up plate to bridge between the two sides of the old point plate and you
are going to mount it so that it is below the old point plate. This is
difficult to describe in words but it will be obvious when you have the parts
in your hands. This new mounting drops the pickup unit down just enough to
allow the magnets to trigger the unit and for the high tension rotor to clear.
Install a small grommet for the leads to exit the distributor. Put a black
sleeve over the two wires if you want to disguise the conversion and connect
the wires to the coils as indicated in the instruction sheet.
Note the LU142 is for negative ground cars only and can be used only on coils
that have 1.5 ohms of resistance. This would be all normal coils but probably
not the Lucas Sport HV sport coil. Pertronix make a compatible extra high
voltage coil to go with the unit. The tech rep at Pertronix told me that they
now have a unit for positive ground cars, but I don't have that part number.
He told me that my conversion should be fine from a heat point of view. I was
a little worried about heat sinking the pickup unit. He also told me that
they don't have a custom designed XPAG unit because of lack of
demand......wonder why??
The pickup unit contains a Hall effect device that turns off a transistor when
one of the four magnets pass by. Dead simple and reliable. Your mechanical
advance will continue to operate normally if it isn't stuck in old grease or
rusted shut. Timing the car is done normally by rotating the distributor
except instead of the old reliable test light across the points, rig the no.1
plug lead so you can watch it fire as you rotate the distributor. Top dead
center or a little advance is the ticket.....
Happy Motoring....
TATerry
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