It's never what you think it is.
Problem: Rough running XPAG (TD) engine, all speeds, loaded/unloaded,
all mixtures, all temperatures.
Therapy: Replace plugs, plug wires, rotor, cap, condensor, coil,
clean and adjust points, adjust timing. Adjust mixture via
lift-the-pot and colourtune. Check fuel pump. No seegar.
Suggestions: "Maybe it's sticky valves" (have newly-installed
bronze guides). But roughness occurs at all speeds, hot or cold. I
lift the valve cover, let it run at idle, put feeler under each
rocker. No tangible difference when roughness occurs.
"Maybe it's bad gas" (gas is about a year old). I drain the gas (what
a mess!) and refuel. After a few minutes to flush old gas out of the
line and the pump, engine is still rough.
So I took out the distributor and stared at it. Nothing better to do.
Sometimes staring is good.
Used the magnifiers while staring, being a blind OF. I noticed a bit
of wear on the top edge of the projection on the points that rubs
against the cam. Looking kinda sideways, I noticed that the movable
part of the points was not quite vertical.
Another case of LLL (Laid Low by Lucas).
The pivot on which the moving point mounts is a brass pin that is
press fit into the mounting plate. This pin had come loose. Because
of the spring tension, the projection that rubs on the cam was raised
a bit, causing it to rub also on the underside of the rotor. This
friction prevented the points from returning properly.
Put 75 miles on the TD yesterday. Wind is fun.
A. B. Bonds
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