Ferret ignition

[MiketheBike]

On a Ferret, what do the filter unit and ignition junction box do?

 

Is there anything in them that could break down, that would cause bad running when the engine is hot?

 

I can see from the circuit diagram that the filter unit has a couple of coils and capacitors going to earth, and then on towards the coil...I wondered if these could be the problem with my never-ending hot running issues?

[Marmite!!]

Everything you need to know about B60 Ignition...

 

http://www.hmvf.co.uk/pdf/IGNITIONMATTERS.pdf

 

I changed the plugs in my Ferret to RSN12Y's & it ran a lot better than with the platinum tip plugs when hot...

[MiketheBike]

Thanks Lee....I should have known to look there to start with...my search did not bring Clive's doc up. As usual...a great read!!!

 

I have champions, but I think they are RSN13P? Maybe a switch to the 12Y's will be one of my first steps, and mean I only need to keep one type in my toolbag for that and the landy

 

Cheers

 

Mick

[MiketheBike]

Mmm...well, I tried testing the filter unit, luckily I have a spare engine with all the ancilleries to compare

When I tested the spare, using a digital meter, when connecting across the "IGN" terminal in the connection box and earth...I can see about 300ohm, and then increasing within about 1 second to over 1M (all very rough measurements). When I reverse the polarity, I see the same readings. I assume this is the capacitors charging up.

 

When I checked the one on the ferret, its almost a short (I need to redo those tests with the wires disconnected to make sure I am reading it all correctly), without the ignition switch etc connected.

 

While I had the coil and connection box opened up, I thought I may as well disconnect the filter unit, and run a wire direct from the "SW" on the coil, to the "IGN" connector in the connection box and give it a run.

 

Well...its the smoothest its ever run, with none of the spluttering under load. The timing does seem to be out, but will have a look at that tomorrow. I wonder if the capacitors have failed in the filter unit?

[fv1609]

Mike I expect the difference in readings is dependant on whether the points are open or not.

 

In the first instance the points are open & you are charging up the capacitor in the distributor. In the second instance the points are closed & you are measuring the resistance of the primary of the ignition coil which is about 3.5 ohms.

 

If it is running better with the filter bypassed then test that. The resistance should be less than 0.01 ohms. The capacitors would get pretty hot in use if they were succeeding in leaking LT to earth away from the coil. You could try removing them to eliminate them from the inquiries. (But in theory it could be illegal to remove interference suppression components if it results in raising levels of radiated interference above permitted EU levels:-\)

[MiketheBike]

Thanks Clive...I will check that out...completely forgot abou the points. I will test with both ends of the filter unit disconnected at the coil and connection box