Posted From: 188.8.131.52
|Posted on Saturday, 03 January, 2015 - 07:30 am: |
Ignition coil is a special type of transformer. Ignition coils have open magnetic flux which makes a bad transformer but a good coil.
The ratio of input to output is the same as the number of windings of the primary and secondary. The secondary is high tension.
Eg 12v in and 12kv out 100 primary windings and 100,000 secondary.
There two types, wet coil and dry coil.
RR use wet coil, which is std brit car.
The primary ohms for Lucas coils are.
DLB 101 Std 12v 3 ohms. £18
DLB 105 sport 12v 3 ohms.£22
These two coils are for brit cars without ballast. The sport coil has more secondary windings and is for MGs etc.
DLB 102 Std 12v
Ballasted coil 1.5 ohms £19
DLB 110 sport 12v
Ballasted coil 1.5 ohms £27
DLB 198 electronic ignition 12v 1 ohm £23
Ballast resistor 1.6 ohms pattern part AES Ltd. Part no 060703. :£5.
Note that a ballasted coil at 1.5 ohms and a ballast at 1.6 ohms in series gives 3.1 ohms which is about the same as a non ballasted coil.
Dizzy caps and rotor. The centre brush is carbon and is the same as any Lucas cap brush. Or use any make and sand down to fit. Or any motor brush. Or very soft pencil lead. The rotor arm end does not touch the cap segments there is an air gap. Dirt on the rotor or cap segments won't stop the HT. The dirt should be wiped off, but polishing the rotor etc will not make any difference. WD40 fixes.
Warning WD40 propellant is butane and is inflamable and I have seen it blow up inside a dizzy cap. I have never seen any damage caused. But it might. So allow 2 mins before cranking if WD40 has been sprayed directly in the distributor.
The cap and rotor are both standard Lucas 8 cylinder parts. Black is usually points and blue is usually electronic. The obvious source is Rover.
The condenser is matched to the coil and ballast ohms if no ballast then the coil ohms only.
The condenser and coil are a tuned circuit. The first spark at the plug ionizes the gap. As the capacitor or condenser discharges back through the primary windings of the coil is bounces and causes the coil to ring. This prolongs the spark.
AES is Auto Electrical Supplies.
(Message approved by david_gore)