THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

Whilst out for a Sunday drive, my S suddenly lost power. At first I thought it was a fuel problem, having checked all leads to dizzy, coil etc.
Trip home on the back of a tow truck ! Called the local Auto Club and mechanic called out to view the car.
A bit of info, which may or may not be relevant - I recently had electronic ignition fitted, new coil, old dizzy, rotor & cap.
So, I have power to the coil and the dizzy cap, BUT no power to the spark plug leads. Yes, I did ensure that they had a good fit to the cap.
The mechanic thinks it may possibly be a "short" down the rotor spindle.
I pulled the rotor off, after a bit of a tussle (rust !) gave it a clean and also the points in the cap.
Still no go !.
Do you think I'm looking at a new dizzy ???
Thanks....

Is the centre brush in your distributor cap making contact with the rotor? Seems not. The spring behind it might also have given up or the "brush" is simply worn out. They cost about $11 because no one wants to make them any longer. I would just buy a new distributor cap. Cost between $15 & $50 depending on whose name you want on the thing. Most come out of the same plant. Comes with new brush & spring. You are losing spark between the coil/distributor cap centre & the rotor.

You say you have had electronic ignition fitted but you stated "OLD DIZZY". Is you distributor old as in fitted with points and condenser or is it an old electronic distributor with a module in place of the points.
If it is the latter it could be the module that has failed. This happened to me several years ago when I had a positive earth electronic distributor on the car. The module failed and it was just as cheap to buy a complete Neg earth electronic distributor and change the cars polarity than to buy a Positive module replacement.
No brainer to me so new Neg earth distributor bought and fitted and the car changed to Neg earth.

I hope you are using the uprated red distributor rotor available from Moss or the Distributor Doctor. The older after market black ones do short out suddenly from the contact arm rivet to the clip that holds it to the distributor cam and leave you stranded. I had two instances of failures of the black one before I learned of this common issue.

This is the correct rotor. No stud. Ultrasonic welded well away from the distributor shaft. Distributor Doctor red Rotors are also OK. Direct copy of the real thing. Excuse/ignore my decision to move away from points. I hate the damn things & setting dwell angle. Pertronix unit available both Positive & Negative earth.


Original Lucas.

Thanks for all the comments.
New cap ordered and managed to source the red Bosch rotor for $2.00 (clearance sale), so ordered 2, must be the Scottish in me !!
Fingers crossed that this will fix my issue - if not I may be back with further questions.
Cheers.

Just make sure that it is the correct rotor for a Lucas distributor cap or it will either smash the cap or have too large a gap to jump to the cap contacts.

I always thought that this had been standardised in the industry until I learnt to my cost this was not so & destroyed a cap on one of my Alfa's as a kid.
This might now have been standardised in the intervening time & my comment outdated.

And reset the timing after fitting.

Please insert your location ~ this is a global forum & it makes life so much easier for all.

New cap & rotor fitted and all good once again.

Good news. So it was the brush & spring in the center of the cap. Makes all the sense in the world.