Coil Problem ?

[Simon T]

Hi All,

Can anyone advise a new novice member as to a problem with the herald 1360 Ive just aquired, All was going well with a couple of local drives to get used to driving an old car again when out of the blue it wouldnt start in the garage one morning. On an initial inspection I found petrol was getting to the carb so a quick look over the ignition system showed up a mouse nibbled! coil lead  and a weak spark to the distributor cap so i replaced the lead with a new one and tried to start the engine. It ran to a fashion but very lumpy with every touch of the accelerator causing a stall. I noticed that while running lumpy the coil was getting very hot, could this be the problem, a faulty coil perhaps or should i be looking somewhere else, as you can probably tell i am a novice to all this so any help would be really great,

Cheers,  

[Pete Lewis]

Simon, there are a number of problems in the coil arna

 

  it gets hot,...  this is quite normal..  hand hot  to quite hot     very /.excessively hot  unable to touch  is not normal

 

   if you have a cheap meter  check the resistance across the blade terminals  there are two coils 

   1.5 ohms forcars with a ballasted reduced operationg voltage around 6 -8 volts on the ignition feed,

    3 ohms for coils fed direct with 12-14 volts  

    run a 1.5 on 12v and it will get very hot.

 

    other things are duff condensers, can increase the current used and cause lumpy misfiring .  

 

  rotor arms with a rivet in the sweep plate are known failures and cause misfire/lumpy running  out of the blue .   best are red ones. 

 

     if you leave the ignition switched on for long periods with the points in a closed position you will soon heat up  any  coil

 

     both rotor and condensers can fail without any pre warning 

 

      check there is no corrosion in the coil sunken HT connector

      check the condenser is secure

      check the small braided wire which earths the dizzy top plate to the side screw is not fractured inside the cotton braiding 

      check the polarity of the coil,,   if its neg earth at the battery then the wire to the dizzy is on the neg coil terminal

      and the white ign feed is on the +pos 

 

  that will do for now 

Pete

[Simon T]

Cheers Pete,

great advice, I dont have a meter as yet so will start with the other checks and replacement of the rotor and condenser etc, once again many thanks,

Simon.

[Simon T]

Thanks once again Pete,

Popped down to my local euro parts (formerly Lucas) today, 1 rotar arm, 1 set of points and a condenser for £ 10.33 off the shelf. Started to change them one at a time to isolate the problem, Started with the rotar arm, no difference, next the condenser and bingo! one smooth running herald.

Simon

[Pete Lewis]

think it was in a PC mag  because of so many aftermarket failures they cut a condenser up to find it only had a few mm of waxed foil inside,

   it should have 9metres  or something like that. hence that little shiny thing is a gutless wonder , so no buffering and blown points and rotors 

     with rivets allow the spark to jump to earth on the cam.   

             Grrr  

                Pete

[PJM Stag]

Make sure you get rid of the mouse too