No spark

[UAB807F]

Hi Frank,

I'm afraid my fault diagnosis is far less technical than yours, maybe something to do with many years spent without a voltmeter

No spark at the points and I generally start with replacing or clean/reset the points plus a new condenser, usually with the distributor out so that I don't inadvertently earth the internal wiring. In the days when I ran contact breaker ignition I'd have a spare "internals" set in the boot. (in fact even with electronic ignition I still have a spare set)

At the same time I check the rotor arm/distributor cap for burns or tracking, although that doesn't appear to be an issue in your case as it sounds like the LT circuit that's at fault. If I was in the workshop I'd then wire it up with no radio suppressor off the coil. It's a simple circuit and with so few components my approach was one of just swopping out components until it worked....

Incidentally, was the original coil a non-ballast resistor coil as well ?

[rgh0]

I would guess a high voltage insulation breakdown inside the coil causing the high voltage side of the coil to short to earth when the voltage builds up but before it get high enough to form a spark at the plug. Try a new coil.

It could also be an open circuit failure of the condenser but if no spark even at low speed this is unlikely

regards
Rohan

[petersracing]

I had this the other day and the low tension lead had dissolved into nothingness.

[fashford]

Thanks folks. I'll swap out the HT and LT components and report back. Thanks again.

[bob_rich]

Hi Frank

Take off the High Voltage lead from the coil to the distributor cap at the coil. Fit a short lead from the coil high voltage terminal and affix the other end around 1/4" from earth. A short length of ordinary hook up wire should do while it may break down that is what you wish to see. Crank the engine with ignition on and a good spark should be seen across the 1/4" gap at the end of the wire.

In doing this just be mindful that U dont have a fuel leak so the external spark does not give U further problems.

If the coil cant give a spark when all your earlier tests showed the circuit was basically OK then first check points actually open with distributor cam then suspect could be capacitor ( condenser) as this is the cheapest and then finally the coil.

best of luck

Bob

[fashford]

Well, it turned out there were two problems instead of one. The easy one was solved replacing the HT line from coil to distributor. The second one was a periodically shorting connection at the tach.

Obviously, thanks for your input. I've still things to work on but I can drive it around now!

Frank