• David Bracey
    17 May 2014 at 22:14 #50798

    Hi everyone,

    I’m hoping to benefit from the collective knowledge of our community. I’ve done about 350 miles in my LG45 since finishing it a week ago and have had a number of problems with hot plugs and leads.

    My car had a single Scintilla Vertex mag and also a coil ignition distributor, both of which I’ve retained. The distributor feeds to the plugs on the exhaust side. The magneto has been unreliable and when it fails I have had plugs and leads overheating on the distributor side – presumably because of un burnt fuel entering the exhaust system and causing overheating which in turn melts plug leads.

    I’ve now got the mag working again but can’t help thinking that a pair of modern coil distributors is the way forward. What have other owners done? I aim to cover several thousand miles each year in this car and it needs to be reliable.

    Thanks in advance.


    Colin M34
    18 May 2014 at 09:16 #50799

    Hello David

    Glad to hear you have got your car on the road. IMHO Scintilla Vertex magnetos are pretty reliable and are still used in light aircraft so they can’t be that bad. I suggest you first take a look at the condenser and then perhaps send it to a specialist for checking/ rebuilding. If you send me a private message I will provide details of who I have used.

    Colin M34

    18 May 2014 at 09:33 #50801

    Hi David,
    Coincidentally my LG6 has exactly the same set up. When I bought the car, the magneto worked, but the distributor side packed up fairly quickly as the rotor arm burnt through. It was a new one made by “Park”. There was a spare “Park” one with the car so I fitted that, and that lasted about two weeks. I then fitted a very well used Lucas rotor arm….end of trouble. So watch what parts you buy!

    Not long after I enjoyed distributor reliability, the Vertex magneto packed up (despite having been rebuilt by D H Day not many miles previously). I’ve yet to resolve the problem, but it is useful for switching on whilst driving through tunnels to enjoy the backfires. Anyway….had no problems with the distributor or its wiring overheating, and like yours, it feeds the exhaust side.

    I have a stainless exhaust manifold, but I would imagine that would perhaps radiate more heat than the original cast iron version. I doubt unburnt fuel is your problem; whilst there is doubtless some, it will be no more than that not fired by a normal single ignition engine. More likely, I would think, is that your ignition timing is out, or bearing in mind care might not have been exercised in choosing that distributor, that the centrifugal advance curve is unsuitable.

    At least with a twin ignition system, you have two bites at the reliability cherry!


    18 May 2014 at 17:21 #50802

    I run two LG45s, a saloon and LG45R, both are on scintilla vertex and, fingers-crossed, have proved very reliable in the last eight or so years. I had all of them rebuilt by Adrian Gorvin. When I was racing my LG45 Team Rep I did play about with various options and then I needed FIA passport but returned to the vertex mags. I am careful with the timing and do not let them advance beyond around 29 btdc and try and get a 2 deg separation with the mags. Hope that helps.


    David Bracey
    19 May 2014 at 14:44 #50803

    Thanks everyone – that is all very helpful. I suspect that my magneto is failing when it gets hot and that my distributor is an early model probably not best suited to this car. The advice appears to be that properly set up working magnetos are quite up to the job so that is where I will be heading.

    Tom Dark Engineering have offered to refurbish my magneto while I wait – well, it’s a 2.5 hour wait – and another ex-member of the club has offered me a reconditioned one as well so I should be in business.

    Thanks again.


    19 May 2014 at 17:17 #50804

    With my M45 I used a jaguar distributor on the exhaust side which is an easy alternative to use. I got fed up with having the magneto rebuilt by so called experts and therefore converted it to a “distributor”. If you are using a Scintilla (horizontal type GN6) this is a very easy conversion. The coil for the mag is tucked away out of sight down below on the chassis and the condenser can be mounted externally on the mag. You use the usual mag points to break the spark. The only obvious difference was an HT cable going in where the earth wire for the mag normally comes out. A mounting internally for the HT cable (holding it against the point normally connected to the mag coil) is the only other thing required. An advantage with this system is that there is a better spark for starting and a spare coil and condenser can be carried at minimum expense.

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