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fv1609

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Posts posted by fv1609

  1. The coil may have been changed from 6v to 12v if the ballast resistor has been removed. The original clamp with its warning may have been loosened & a 12v coil slid in. A Lucas coil should have the part number & date code stamped on the base (flat bit), this will indicate if it is 6v or 12v coil.

    Maybe the ballast resistor failed & a 12v coil fitted as a temporary fix or maybe someone thought they knew better than the designers & having a 6v coil + ballast resistor was a silly complication?

    Wired with a 12v coil it will still run but the performance will not be so good at high revs because the extra inductance of a 12v coil over a 6v coil slows down the rate at which the coil can magnetise & demagnetise.

    In other words loading the primary with more resistance & less inductance reduces the time constant of the circuit.

     

  2. Wherever the resistor is located it might be as well to do some preliminary checks as it may be quite ok..

    The coil is a 16C6 & would have a resistance of about 1.5 ohms, the ballast resistor would have a similar resistance.

    With the ignition on but not started, you should get 12v on the +ve terminal of the coil.

    When you close the points this should drop to 6v. This would confirm that the ballast resistor is working.

    It looks as if the ballast resistor is short circuited on running the starter motor.

    Incidentally the ambulance UHB says that the basic electrical system is the same as fitted to the 12v GS.

  3. Please post some pictures of around the coil & of the inside of the filter box. It is very difficult to visualise your set up.

    From the title of the thread & at the outset you asked for the location of the ballast resistor, by that I assumed you had a 24v system. But perhaps this is not the case & it is 12v, in that case I wouldn't expect there to be a ballast resistor.

    Do you think all the wiring is original or maybe a previous owner has made modifications?

  4. John wow melted solder that was getting hot!

    Picking up on your point about a newly manufactured good quality condenser, I agree but it doesn't matter whether the condenser was intended for a 6v, 12v or 24v system. I just use condensers for a car (ie 12v) in 24v systems.

    It doesn't matter what the voltage is of the LT energising the coil, it is the Back EMF that comes from collapse of the magnetic field when the LT is turned off (ie points open) that counts. This is typically 300v so condensers for distributors will usually be rated for 500v although they rarely state that!

    If you see any sparks as the CB opens that is the 300v, it is not the LT supply.

    I've met a lot of people over the years who have wasted good money on "24v condensers" when a normal car one will do provided you find one of a similar size & clamp configuration.

    Because of the high ratio of secondary coil turns to primary turns, the Back EMF on the secondary is much higher than on the primary. Provided the coil is one designed for the earth system of your vehicle then this 300v will be of the correct polarity & be added to your HT.

    If you have vehicle where the earth polarity was changed & someone has just swapped over the coil LT connections then this 300v will be of the wrong polarity & detract from the overall HT output.

    Using a coil of the wrong polarity for your earth system means your HT system is 600v worse off than using the correct polarity coil.

  5. The ballast resistor is inside the filter box & that will be a few inches away from the coil, given that the screened cable is quite short.

    If you are getting sparks at the points it shows that there is continuity through the filter box & the ballast resistor is likely to be ok.

    You shouldn't really be getting sparks at the CB points, it is the job of the condenser to minimise this & maybe you have the signs of a failing condenser. This would not only show itself by allowing sparks but the spark will erode the points (think of how an arc welder works).

    The consequence of a spark is that it slows the collapse of the magnetic field of the coil thereby producing reduced HT. For maximum HT you need an abrupt switching off of the voltage to the coil & a good condenser should provide this.

  6. Sam do not buy an official B Series condenser. Even unused it will be quite old & will have deteriorated internally. Even years ago I remember people paying around £50 for the "proper condenser" an utter waste of money.

    Use any new 0.2mfd distributor condenser that will fit inside. You must use a distributor condenser as it will be rated at 500v, do not use 0.2mfd condenser other than one designed for a distributor.

    • Like 1
  7. All good stuff Wally. In this treasure trove are there any pictures of that Hornet model when it was intended to be the Orange William launcher? I have a picture of it, probably at the changeover period to Malkara when there is a strange hemisphere over the controller's windscreen. But there is some labelling that has been deliberately obliterated that I suspect may have referred to Orange William?

    On the subject of OW are the any models of the other proposed launcher FV426 I wonder?

  8. Field repairs on the showground can be a challenge.

    "Have you broken it mate?"

    "Do you want a hammer?"

    On such occasions I wish I had one of those workman's tent/shelters you used to see when carrying out repairs to cables/pipes at the roadside. I found wearing headphones or ear defenders gave some discouragement to the passing comedians & greatly satisfying when their companion would say "He can't hear you, he got his ears covered".

    Humourless this may sound but it can be a source of great stress worrying whether you will be able to effect a repair to get you home, without having to provide material for passing comedians.

    An additional anxiety is the tool box, if on the ground, kids rummage & try to walk off with bits.

    I have noticed that a raised bonnet & a tool box can quickly draw a crowd. If I am doing some minor adjustment or repair, I'm quiet happy to provide chat but not if it is a crisis repair, I just want to be left alone.

    I carry in the vehicle a comprehensive range of electrical test equipment (5kV Megger, multimeter, inductance meter, HT tester, cable fault tracer, DC clamp ammeter, coil testing device etc). If I see a raised bonnet & a tool box as I pass, I mention that if it is thought to be an electrical fault I have a range of test equipment which may help, then walk on.

    The response from the distressed owner can be quite varied from bluntly dismissive to an invitation to help. In the former category if I see a distributor condenser that has been removed, I do poke my nose in & ask if they would like me to test it. Frequently I am told that it has been tested on a multimeter & there is no short circuit. But you cannot effectively test a condenser like that.

    It is a difficult decision to press the issue knowing that you can be of help if the owner had a more open mind or to walk away. There have been occasions that having walked away some time later the owner, having explored all advice from their group of experts that they are prepared to hear what might else be tried.

     

     

    • Like 1
  9. 10 hours ago, David Herbert said:

    I know that the two speed generators do give trouble occasionally

     

    The main cause of failure is the bearings packing up due to lack of lubrication. The generator gearbox needs to be primed with a quarter of a pint of engine oil if the engine has not been run 3 weeks or more. Many owners fail to do this & boast that they have as yet had no failure, but when failure comes messing around with the generator gearbox & clutch is a nightmare that requires special tools.

  10. 13 minutes ago, B series said:

    b) It current is fitted with generator No1 Mk2 FV141545 which is spec for cargo vehicle, but it has a generator panel No2 M2/1 (FFW), there are no spare leads or disconnected plugs on the vehicle and it all looks complete as it left the army, will this combination work the charging system?

    c) What are the diffrences between a B40 Mk 5A cargo engine, and a Mk 5A FFW engine other than the generator?

    d) To correct this mismatch of parts if required, do Champ experts think it would be better / easier to find a FFW generator, or change to a No 1 Mk 2 or 2/1 Cargo generator panel ?

    b) It seems that you can get away directly fitting a Gen Panel No.2 in place of the Gen Panel No.1

    c) The FFW engine will be fitted with an engine oil feed to lubricate the gearbox in the Gen No.2 & a drain out to the sump. Not sure whether the Gen cradle may be different.

    d) I am not a Champ expert, but it would be very difficult to find either type of Gen Panel No.1. They are very rare & I suspect more troublesome. The reason for the greater abundance of Gen Panel No.2 was that large numbers were re-manufactured for Pigs in NI. Of course not all Pigs had Gen No.2 but on failure those that had Gen No.1 were fitted with Gen No.2 & matching panel.

  11. 20 minutes ago, wally dugan said:

    The top photo is for clive 

    Much appreciated it is too Wally. Lovely to see that High Gloss DBG twinkling in the Sunshine, so very British 60s.

    The trailer went through quite a bit of change, not seen such an early example before.

    Dscf2165a.thumb.jpg.900da098f36e14e93476e7e686ed05ac.jpg

     

     

     

    • Like 1
  12. GDSF have taken payments from the public for camping but are offering a carry-over to 2021 or a refund.

    WPR still seems to be off line, it will be interesting to see if the same sense of fair play exists at least as far a carry-over to 2021 goes. If it does not it will generate a vast amount of ill feeling & a suspicion that even swallowing your loss for this year, could they ever be trusted again should you decide to pay again for next year if some no refund cancellation occurred again?

    A scenario could be a few enthusiastic & trusting exhibitors paying again to enter next year, for the organisers to realise there has been such a breakdown in trust, that they have relatively few entrants that it is no longer viable to run it again next year & those trusting exhibitors get stung a second time?

    Such a cycle of mistrust would be the end of the event & nobody wins.

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