Ignition problems

[partridgekelley]

I know you are orininal model A guys. But I can't figure this one out! I have a Mallory distributor and a marine performance coil , running 12 volts. This set up was running rough at higher speed. I changed everything=points,condenser,coil, distributor, even the carburator. Nothing changed! Than I added another condenser and it ran good at all speeds. I don't understand enough about electric's to know what's going on. Can anyone explain this? I have been playing model A's over 50 years and never had this problem. HELP!!

 

[steve s]

I'm assuming that you added the second condensor in parallel with the first. Sounds to me like there are only two possibilities: either the condensors are of too-low capacity, or there was some unhappy connection that finally got jiggled just right. I would try to measure their capacitance, and then see if you can find one with the same TOTAL capacitance.

 

[jburessr]

I have run across this problem several times in the marine industry, there are several things that can be at fault. The points are not firing right or even double firing. this is caused by an oil film under the points or condenser (not grounding good) weak spring tension on point arm, spark jumping between the points itself (bad set of points) High output coil over powering the system (bad grounds or wrong coil for system) Coil connected backwards, distributor not grounded good. not having the proper voltage feeding system, bad or lose rotor contact. and the list can go on but these are the most common things you'll find.

 

[29restorod]

Just last week I had the same problem with my Mallory distributor. It had a NEW condenser,and a 6Volt Mallory antique coil. It ran fine at 45 MPH,but started to miss under load at around 50MPH. I changed condensers again to a 70's Ford condenser. Now it runs smooth at all speeds. I have heard that condensers are made differently today than years ago. It seems that the selenium insulating material is no longer made,because of health problems. A great deal of people are having condenser failure in just a short time. I keep two spare condensers in both of my point equiped cars.