Section : Ignition and Distributers

New points and new coil problems

Posted By : Peter Kristoffersson, 06-Apr-2004, 12:45pm

Hi

I just changed my contact points and coil last week and had a few problems with idle speeds, choke and start. So I am trying to narrow down the problem.

Is it possible that a set of new contact points will alter how the engine behaves, in this case will make it harder/ impossible for it to idle without choke? Might this have to do with the distance between the points?

Can a new coil do the same?

Where exactly is the ballast resistor situated on a 72 MK3?

Is a Lucas DLB102 coil correct for a 72 MK3 with ballast resistor?

Please help!
(Car died in traffic on Sunday afternoon after new points and new coil were installed)

Peter

Followups :

New points and new coil problems

Posted By : Graham Reeks, 06-Apr-2004, 02:38pm

Peter

The points gap will definitely affect this - set as indicated in any appropriate manual that you've got. If you haven't got one, get one!

Also, it's useful to get this really well measured by measuring the dwell angle. You can get this as one of the functions of a timing light - again the correct setting is in a manual. This method is good if you're not keen on using feeler gauges!

Ballast resistor is radiator side of the coil usually - it looks like a block of white plastic. I'm not sure of the code but if that coil is a 'sports coil' then you can bypass or remove it, I believe.
- New points and new coil problems
  
  Posted By : Peter Kristoffersson, 06-Apr-2004, 03:02pm
  
  thanks
  
  Is the resistor immediately to the left of the coil or somewhere in between the cables?
  
  I guess it was the gap I messed up
  
  cheers,
  peter
New points and new coil problems

Posted By : David Rumens, 06-Apr-2004, 06:48pm

Just add my bit. The points may have some protective grease on the contacts and it is always worth cleaning then when fitting.
- New points and new coil problems
  
  Posted By : Graham Williams, 24-Jun-2007, 07:33pm
  
  I now own this car, I think.
  
  According to my Triumph Workshop Manual, this car had a "KW" resistor wire for a ballast resistor. Assuming this means Pink White, I've found this wire is still in place. What affect would this have, considering a 12V, rather than a 6V coil had been installed?
  
  I recently got the car back on the road after seven month of brakes, suspension etc repairs to get it through the MOT. Having rebuilt the carbs, changed the dissie cap, leads, plugs, and points it got through. However, I then went for a drive and ended up returning on the back of a flatbed due to backfiring/misfirng during acceleration - coming off roundabouts on a section of dual carriageway etc. I've since changed the condenser as well, but I'm still getting misfires. I'm now considering changing the coil. If I do, should I go for a 12 V or 6V, and if 12V how do I bypass the resistor/do I have to put a different resistor in its place?
  - New points and new coil problems
    
    Posted By : Peter & Mick Lewis, 24-Jun-2007, 08:15pm
    
    with a simple multi meter measure the voltage at the coil low tension terminals,, with ignition on 8volt means you need a 1.5 ohm coil...as the ballast wire is doing its job..
    12volt needs a 3 ohm coil, if not marked you need to check the coils resistance,
    if you have a 12v coil on a 8 volt circuit and your spark voltage is less than useless....pete
    - New points and new coil problems
      
      Posted By : Graham Williams, 24-Jun-2007, 08:45pm
      
      When I put a multimeter across it, I got between 4 and 5 V with just the ignition on. Running, it varied between a max of 9 to 10 right down to about 2 V. (Assuming you mean between the + and - terminals on the top of the coil.
      - New points and new coil problems
        
        Posted By : Peter & Mick Lewis, 25-Jun-2007, 10:47am
        
        graham, sorry I was'nt clear check between ign feed terminal on coil and earth as checking across the coil will give you odd results . some cars have a seperate ballast resistor some have it built into the loom with resistive wire,
        if you use a aldon ignitor instead of points the will run on 6v to 18v so not a problem but the coil has to be right for the voltage supplied to it or weedy sparks are most likely..
        the split voltage idea is that when cranking up the coil should be supplied with a shot of 12volts and when runniing the wire or ballast drops it to around 8volts, it was an aid to cold starting voltage drop peter
        
        New points and new coil problems
        
        Posted By : Graham Williams, 25-Jun-2007, 10:24pm
        
        Thanks for clarifying -the voltage between the feed wire and the earth is 12V. The resitance of the coil, when disconnected from the rest of the circuit, appears to be about 0.8 to 0.9 ohms. I'm going to change the coil for a 12 V Sports coil. A local(ish) member with experience of bypassing ballast resistors has offered to help to ensure it definitely is bypassed! Currently I use points, but I'm considering changing to electronic ignition.
        
        New points and new coil problems
        
        Posted By : Barry Huffer, 26-Jun-2007, 12:27pm
        
        If you are going to change the coil and thinking of electronic ignition have a look at the Aldon(UK)/Pertronix(USA) Ignitor ignition and Flamethrower coils and the prices at http://www.lbcarco.com/.
        
        For a Spitfire IV the combined cost is about $120 -130 including packaging delivered in 3 -4 days from the States, the ignitor can cost that from Aldon in the UK.
        
        If you want some good spark plug leads they supply Magnecor at an equally competitive price.
        
        Usual caveat about connections, relatives etc only reasons for suggesting them are their excellent prices and service.
        
        Regards
        
        New points and new coil problems
        
        Posted By : Stephen Williams, 26-Jun-2007, 08:50pm
        
        I got my electronic ignition from http://www.vintageperformance.com/retrorockets/ they have a warehouse in the UK and are posted from there not the USA. Cost was Â£45 plus postage and the unit arrived next day. They sell the flame thrower coils as well.
        
        I will say I had a little trouble fitting it to my Delco dizzy (had to file the mounting plate a bit). Once fitted though I am getting a much fatter spark (Lucas Sports coil) and the timing is very even. I had the dizzy re-conned by Dave at Canley Classics a year ago but it still splashed around the timing mark at tickover. Now its right on the line. Tickover is much smoother (Webers considering) and pickup seems cleaner.
        
        Bypassing the ballast resistor should be very simple once you find it. Just take the thing off and join the two wires together.
        
        New points and new coil problems
        
        Posted By : Graham Williams, 27-Jun-2007, 06:48pm
        
        Thanks all for your help.
        
        I've just ordered a Pertronix Electronic Ignition from Retrorockets. To go with this, I'm getting a 12 V Sports Coil, a new ignition switch and a new Starter Solenoid.
        
        New points and new coil problems
        
        Posted By : Peter & Mick Lewis, 27-Jun-2007, 10:22pm
        
        If you spash out and get a hi torque geared starter it will fling it over at a heck of a rate and uses no current like the bendix type
        so the need for low voltage coils dosn't arise,, on of the best upgrades you can do,,,,, hope it all gets sorted
        ready for some sunshine Peter
        
        New points and new coil problems
        
        Posted By : Graham Williams, 19-Jul-2007, 09:38pm
        
        Thanks all for your help. Having installed the new ignition switch, starter solenoid, Sports Coil and Ignitor the engine has run well, usually starting first time.
        
        I've used the car for the last four days to get to and from work. Just seems to have developed a gearbox problem......