Back home! Forgive me for returning to this subject.
But I fear that the information left as it was could lead to significant sadness for the Plus 8 crowd (mid-1980s to 2000 (or 1996 for the
USA). I have a soft spot for them.
L, as ever I admit to being easily confused and like to keep things simple to aid my understanding.... I do not understand the need for an internally ballasted coil if one such exists,
I have never found you confused on such things Luddite, not in the last 25 years!) Yes these coils exist aplenty, at least in their advertising. A simple google will solve that for you. 🙂 Try it.
However I referred specifically to the Mallory Red Top coil (advertised as internally ballast resisted) in contrast with their regular Tan Top. As noted, I found it became too hot for safety and I switched
back to the Tan and a standard ballast resistor I have not gone near such things since.
This seems to be a case where my experience and theory do not match..
but remember, in this area, my knowledge is limited to Rover/LR and Morgan V8s. Rover/LR factory V8 specification came with two types of coil set ups. A 12V coil with the common ceramic ballast resistor which ended sometime in the 1980s and a later 9V coil with the
little beer can/canister/capacitor.
I thank you gentlemen for guiding me to that. The literature is more or less consistent. The beer can absorbs electricity and then releases it. Therefore it produces
a better spark all things being equal. However, That being said Lucas distributors are all substandard. Kevin Vernon and I, along with all others though from what Kevin Vernon and I saw it a degraded
spark compared to Mallory. Mallory Unilites were not only more precisely timed but a stronger spark as well. The Mallory uses at 12V and ceramic ballast resistor. The Mallory diagram I posted above
as can be confirmed by the 100s who use it. Remove the effect of the ballast resistor and the coil gets super hot and stalls the car in 15-20 minutes, burning the coil and so on. The beer can failure
does the same to the 9V system.
At the outset, Rover/LR were worried about the beer can and the consequences of its failure. Les Hamill, the tuner/designer/writer of note, states that they originally recommended that the thingies be
changed at every annual spark plug replacement. That is confirmed by early shop Rover Manuals. But they later changed that advisory to having the thing merely checked regularly as the signs of its
failing appear on the underside, not its visible side. But in the experiences I have seen my experience by the time one notices they are going your entire ignition, coil/amplifier/distributor innards are
gone as well. At the very least, that causes a bad day..but generally it starts a much longer saga. Of course, the beer can +8s can switch to the earlier 12V system. That worked for all Plus 8s made
from between 1968 to the mid 1980s. And ceramic ballast resistors do not fail the in the same way as the beer cans, if they fail at all. BTW, I once accidentally ran my UK mog with the bonnet stay
loose allowing it to cross the ballast resistor terminals. Ran for 15 minutes and stalled, coil (a regular one) burning hot. Burned out the Mallory internal photo optic unit as well ( 2 minutes to swap in
the spare).
Your diagram also confuses me a tad as it displays the ign switch as having one wire from it to the coil + whereas on my car and no doubt others, the ign switch will have two wires feeding the + coil terminal in order to switch the ballast resistor in and out of circuit as required...
Ot os not my ndiagram. It is Mallory's. I have yet to find, in Rover or Morgan diagrams, two wires from the ignition switch to the coil. You may be mistaking the way these ballast resistors work. Or are
you confusing the negative terminal to tach (and ECU)?
Gomog and the internet is full of wiring diagrams for your to confirm. A ballast resistor permanently reduces current and dissipates it through
heat-resistant ceramic. The beer can absorbs electricity for a milli-moment then releases it or so is my understanding. The Mallory diagram works for me and 1000s of others with our engines.
BTW. here is the story on your system.
https://www.nonlintec.com/sprite/cap_failure/ Another sign of pending failure is the car overheats caused by the hyper-heated coil adjacent to it The MMC
diagrams and the LR/Rover L-Jet and Hitachi Hotwire diagrams reflect the Mallory wiring. NAMELY, one wire from the coil, one to the tach (and then on to the ECU if there is one) and the earth. But
by your car, they were incorrect.
Another cause of an ign coil running very hot would be if it is a 9 volt coil (thanks Richard) that is being supplied with 12 or more volts constantly, when it should be supplied with 9 volts THROUGH a ballast resistor AFTER the engine has been initially fired up and now with the ign key in the RUN position..
That is what is happening when the beer can fail.
My Mogs system is to the best of my knowledge as originally fitted to it in the mid 80`s when it was built by the MMC. the only failure to date was on the central HT sprung loaded carbon brush within the dizzy cap causing burning on the rotor arm centre point and misfiring... a replacement cap sorted that issue out..
Actually, the ignition system was built by Rover or LR at that period. And yes. ! I have been there as well. (pow, sputter, bang). I carried and had occasion to use a replacement cap&rotor. This
experience is common to Lucas dizzies. It has never happened since I swapped distributors. Lucky I guess. I appreciate you desire to continue with original equipment (actually our cars were made
during a transition period both ignition and engine source wise). I am a long distance mogger and cannot tolerate the vacation risks that come with some equipment. Lucas is far more complex to deal
with and less reliable than other ignition solutions. Hundreds of owners, have moved to Mallory..which is sadly been cancelled for more profitable fare since the Mallory purchase. But whatever you have,
your car is more reliable and less risky f you switch back to the earlier system, for the reasons given. Either that, or check the underside of your beer can every time you check your motor oil. Carry an
extra beer can with you. They are only 2-3 quid.
Thank you for your help, G & R.
Lorne
P.S. What did Rover/LR switch from one system to one they knew to be less reliable? Best I can figure is that the 9V and beer can is cheaper by 8 quid. 30,000 units x 8 a year.
