What causes dirty ignition points?

Thanks again for all of the advice on dirty/scored points.

BTW - I do not have a "points" file, and instead used a very fine (1000 grit) wet/dry sand paper to clean my points and the car is now running great.
 
Mike V. Florida said:
I thought the good points were made from tungsten? Is tungsten not hard?
Click to expand...

Yes, fairly, about like a grade 5 steel fastener, but here's where quality comes in- It is near impossible to produce solid cast Tungsten blanks from a liquid state. Tungsten blanks for making things like ignition points and TIG electrodes start as powdered metal that is compressed and then heated to a point well below the melting point. The lesser grades are incompletely fused. The higher grades are more completely fused and then post-forged to further refine the structure into a slightly denser grained form. The higher grades can also be cold rolled, annealed and drawn to make wire for lamp filaments. If you're using the Tungsten as balance weights, the lesser grade is fine. If you use it for electrical contacts the lesser grades erode and oxidize faster.

It also depends on what elements, if any, are used to 'dope' the powder used to make the final Tungsten stock.

As to filing vs using an abrasive, they sold metal points files for a reason! If you use any type of abrasive, like silicon carbide, diamond, emery, etc, it is always possible to leave behind microscopic particles of NON-conductive material that will embed in the point material. As the points burn away it is very possible to end up with a micro-particle of embedded abrasive exposed and sticking up just enough to prevent point contact after a thermal cycle, like cooling off and then a restart attempt. If you use the recommended metal point file there will be no hard, non-conductive material that will cause the problem. Points that do not like to work after a rest period are often the victim of embedded abrasive particles. The only 'fix' is a good filing with a metal file or replacement.
 
You must log in or register to reply here.
Back
Top