Uprated Ignition Coils

[cliveyboy]

What uprated ignition coils are people using on their ballasted systems.
The ones readily available are Lucas sport gold DLB110 and Bosch (red top).
What have people used and any experience on which is best.
Clive

[gjz30075]

Clive, I'm using the Lucas Sport coil, gold, but don't have a ballast. I removed the ballast when I installed this coil over 25 yrs ago.

Greg Z.
'72 Sprint

[twincamman]

i just went through this----car would start foul plugs and stop ---went and bought a BLUE BOSCH COIL [ aside from the cultural differences ] problem solved quick starts-- even idle and brown plugs-----life is good ed law

[type26owner]

Clive,
It's prudent to use the lowest voltage coil so as to not overstress the dielectic strength of the insulation of the Lucas ignition components and the plug wires. All new ignition components start out with their highest dielectric value and degrade in use until finally failing. Once they have degraded enough they allow a short circuit to track across or through them to ground. The key is to slow this inevitable degradation process down by not using too high a coil voltage. The higher voltage justs constantly electrically hammers on the insulators speeding up the dielectric degradation process. The best coil voltage is determined by just not allowing a misfire at WOT when the highest air gap resistance is encountered across the spark plug. The flame kernal is generated by the available spark across .020" gapped spark plug and this is an either all or nothing effect. At full throttle are you having the engine misfire cause that's when it will be most noticable? If not, then stick with the stock 25k volt coil and make the ignition system as reliable as possible by not pushing up the voltage unnecessarily.

There's lots of web references supporting what I've stated here.
Regards,
-Keith

[steveww]

As well as using a good coil, Bosch or Lucas go for electronic points; Lumenition magnatronic or Aldon Ignitor. The electronic points will also improve the spark. If you fit electronic points and/or high power coil remember to open up the plug gap to get a bigger spark and better burn. I use 0.8mm (30thou) with the magnatronic and bosch coil

[twincamman]

THE BLUE BOSCH COIL IS INTERALLY BALLISTED the same one we use in formula vee its a bullet proof part-------my engine is t c with 40 dcoe 32 webbwers from an alpha ----i bought the carbs used as no motor came with the elan so i hunted down bits anc pieces to make a motor ----i used the same jetting on my 7 in this motor -- mains 115 air correction150---f11 elmulsion tube ----the idle jets on the alpha set up are more sensitive and require 2 1\2 turns as opposed to 3\4 turns on the lotus set up --- set the crank timing at 5 degrees with the cam marks facing and #1 at tdc i use a unicin to balance the flow at 1000 rpm ---check all is well electronicly points at 16 thou --champion n9yc plugs at 25 thou---when it is running remember carburetter is french for 'leave alone' when performance changes look to the points and regap and clean the plugs when things go 'off' a bit the first thing most people do is diddle the carbs ===then there are two problems to deal withand the webber delorto set gets a bad name let me know how you make out ed law

[type26owner]

The Lucas dizzy cap and rotor are the weak point of the electrical system from the standpoint of withstanding high voltages well and the unwary abuse them. The result is an undeserved reputation which Lucas has gotten over the years for being unreliable. I've got news for you if you tune your ignition system correctly this will not be a problem. It's when the wrong components and settings are applied for the wrong reasons that the system is guaranteed to fail rapidly.

The cap and rotor are old technology and still have the same limitations they have always possesed. They still appear to be a phenolic resin and as such have a rather low dielectric strength of only about 25kv. This is the parameter which dominates the do's and don'ts of the ignition system. Don't install a high voltage output coil even though the actual voltage achieved is only what's required to overcome the resistance to ground. Don't set the spark plug gap open more then what the Lotus manual states or the resistance to ground goes up and therefore the coil voltage has to build up to a higher level each time to jump the extra gap. The very worst combination is to open up the spark gap and install a high voltage coil. Don't be a victim of the dark force and get stranded on the side of the racetrack or the open road through ignorance. Do use the stock components and settings to get excellent reliability and performance. There is more gimmicky useless crap available for ignition systems I think because they are so poorly understood. Beware that there are all tons of counterfeits parts too.

Here's one of many articles which explains the facts about dizzy caps.
<a href='http://www.bwdautomotive.com/datastream/Spring2001_data_stream/page5.html' target='_blank'>http://www.bwdautomotive.com/datastream/Sp...ream/page5.html</a>

-Keith

[twincamman]

I have no failure in 20 years with the super 7 ---i use the standard ford points and caps and distributer rotor ----I expect the same with the elan motor-----its checked and rebuilt every 50 000 miles only because its is becoming so rare it has 170 000 miles on it with all the original block-head-crank etc etc new pistons were added at 100000 so much for poor brit quality [ and it is driven with pinache and enthusiasm ]:rolleyes: ed law

[type26owner]

Ed,
By using a 25 thou gap on the spark plugs you've done exactly what should be done to prolong the lifetime of the cap and rotor. Congrats! You've confirmed my point. Thanks.

It's been awhile since I've researched this stuff so I might have this next statement garbled up but IIRC it's the amount of current delivered which is more important then the voltage to get the best combustion from the spark plug. The amount of voltage just jumps the gap. The amount of current lights the flame kernal consistantly.
-Keith

[twincamman]

I=E\R

[type26owner]

Yep. Kinda silly to deplete the available current then by forcing up the voltage due to raising the resistance path to ground unnecessarily. Just the fundamental principles being applied. Kiss off good radio reception though.
-Keith

[steveww]

V=IxR (Oops a little typo snuck in there :blink: )

Thus the more voltage you have over a given resistance the more current will flow. The more current the hotter the spark. The hotter the spark the better it lights the fuel. Opening up the points gap increases the resitance but gives a bigger spark which creates a bigger flame front.

normal gap 25thou vs bigger gap @ 30thou = 20% increase (ignoring some physics)
typical basic coil gives about 9-12kV
Bosch blue coil 35kV = 200%

Thus opening up the points gap with a sports coil gives a hotter bigger spark and thus a better burn.

OK so it is going to stress the dizzy cap and rotor arm some more but these are consumable parts like brake pads. These parts are cheap and you should always carry spares of these anyway.

When ever you go down the turning route you are always going to stress parts more and cause thing to fail before they would normally. More power/torque puts a greater load on the gearbox, clutch etc it is just the price you have to pay.

[type26owner]

Steve,
Shouldn't that actually be V=I x R to correctly depict one of the forms of Ohm's Law. Pretty sure I've got the correct understanding of the physics of what happens when the primary field collapses in the coil and a finite quantum of energy is generated in the secondary circuit. Best practice is to stay within the electrical capacities of the components by not changing the ratio of Ohm's Law from the stock values.

And you're right I do carry at all times a spare dizzy with cap and plug wires and another good coil at all times. Otherwise expect to get stranded at the most inopportune time possible. It happened to me already.
-Keith
p.s. Just so happens I'm trying to design right now a Mumetal magnetic shield which allows my first-of-a-kind 6 degrees-of-freedom <4K sample manipulator to move through it's range of motion and still allows less then a micro-guass in the area of the x-ray illuminated sample secondary electron emission area of the microscope's hemispherical analyzer. Fun stuff but not my area of expertise!

[twincamman]

radio?????????? my music comes from the exhaust ed

[rickf]

A couple of years ago, I put a new Mallory distributor in a 50 year old MG TD I had at the time and it was like giving it Viagra. It didn't think it had it in it.

Too bad I can't fit one under the intake manifold on the Elan engine. Seems like somebody ought to at least sell a cap and rotor made of better stuff for the Lucas unit.