Responding to Joe B. I was acquiring a lot of Super Elto’s and
they all need the wiring repaired. The coil and the condenser
are in a tube filled with tar. I had figured out how to get the coil
out, clean it up and reuse it but the condenser needed to be
replaced.
Its value is .1mf. I stumbled on to these. They exceeded the 600
volts that was being recommended. I posted them on the board
and asked if they would work before I ordered them and the
response was, they would.
When I tried one of these 1mf caps. I bench tested the assembly
before I filled the tube with wax. The coil would fire on the bench
but the motor wouldn’t run.
I took the coil out again and replaced the cap with a condenser
and it took right off.
Posted my experience and Tom Manley had an explanation that
made sense to me. He said – that condensers have a dV/dT
specification. Dumbing it down for me, the condenser wasn’t fast
enough. That would coincide (in my mind anyway) why it would
fire on the bench but motor wouldn’t run. He gave what the min.
spec. needs to be, and I have it some were, but its something you
would have to search out before you buy.
So its more than just the mf value and the voltage.
Now that I throw the original coil away and use a substitute who
knows what the correct condenser value would be. I have a few
that I favor but its more about how the fit. I can get most of the
ones I prefer at any auto parts store.
It was expanded to me that having the wrong condenser value can
accelerate the point wear but other things can change the actual value
at the points like, the length of the wire, poor connection at the wire,
or a poor ground. All can cause the points to pit prematurely but as
little as these motors get run you probably never notice it. So far that
has worked for me and I believe I run my motors more that most.
Tubs.

Another thread about the Vishay caps.

https://www.aomci.org/forums/topic/substituting-old-condensers-with-modern-capacitors/