fv1609

Being asked to speak about your vehicle in the arena can be daunting & I can well understand people's reserve about about wanting to do this. I am reasonably happy to babble on endlessly about my particular vehicle. What I do find a hindrance is to hear myself echoing through the PA system with a half second delay so I have to carry on talking over myself. This means a certain determination in trying to keep on track what you are trying to say. I don't know whether the isolation of a commentary box cuts out this echo effect. But generally I think commentators do quite well. Its not a job I would want to undertake. Sometimes exhibitors present themselves in vehicles other than the one booked in & the commentator has to think on his feet. I would find this extremely difficult unless the vehicle was a Humber 1 Ton or a Shorland. Given the random way in which vehicles line up for the arena parade, it must be very difficult for a commentator to find interesting things to say about a vehicle of which several have already passed through & possible several more further back in the queue. I think the most skilled at this was David Fletcher of the Tank Museum with his commentaries at GDSF. He always managed to weave a connecting story between the vehicles driving in. These are of course not chronologically presented, their role & country of origin was totally random, yet he was able to string the whole commentary into a coherent, interesting & often amusing story. A particular highlight for me was to stop the Hornet/Malkara near the commentary box & slowly pan the missiles in his direction! But things can vary, one show I took the Wolf & had presented its history on the entry form that it was 51 Sqn RAF Regt & the rear end blown up in Afghanistan. No doubt seeing more action than many of the vehicles at the show. But despite having supplied the history the commentator merely mentioned that it was "a pick up truck & someone has fitted a hard top". So no I didn't bother going round on the other two days.

The Great Dorset Steam Fair wrestled with this problem. A couple of years ago they took a pragmatic view & the show now finishes at 3.00pm on the Sunday with a reduced entrance fee on that day. Slipping out early from a show can be tempting I know. This weekend I went to new show for me but I noticed many slipping out at 4.00pm, I thought this rather unsporting as I had agreed to stay until 5.00pm. This I did but my reward for doing my duty was to queue for 1.5 hours just to leave the site through one entrance/exit. :-(

Someone sent me a request for a copy of the full report via an email through HMVF. I was away from home but tried to reply on my phone but your settings did not allow a reply through the HMVF email system. I have not been able to retrieve this message on the PC at home. The problem is not just finding the document again but I'm afraid I get swamped with requests for scan of documents of their various kinds. I don't mind doing a few odd pages but full scans of things can take a while. Each day I receive one or two requests for documents & I can't keep up I'm afraid. As it is most mornings are written off answering technical queries & looking things up for people. Sorry it's not practical at the moment.

Pages 12-14 http://www.hmvf.co.uk/pdf/IGNITIONMATTERS.pdf

Shame for you. Paradox is that it must have an ok one. If it didn't sell then it might not have a very good one. Trying to approve your Yahoo application but can't log in I'm afraid. Away at show need to do it on home pc.

Nick yes I'm already watching that one out of curiosity. Not sure that the seller has twigged the significance of what he's got. I notice he doesn't show the rear to show the state of the straps & as we know at that sort of age elastic is everything.

Yup. One just sold on ebay for £45. I don't know what proportion were made in that configuration?

I have several S6 respirators already, in fact I sold off a couple recently. But Neil you realise the rare thing about this one?

Ah yes forgot this S6, quite rare I believe.

I think that was Cpl Jones who was very keen to volunteer for the task

Yes heard that shortly after your post, double standards somewhere.:shocked:

National Park, yes tell me about it, we were annexed into one against our will a few years ago :argh:

http://www.theguardian.com/uk-news/2014/jul/28/conman-faces-jail-help-for-heroes-fraud

Mike in the ballasted system at high revs because of the lower time constant of the circuit then the coil current can rise more rapidly. But this is only during a small percentage of its operation & not greatly significant. I would forget about the issues of a ballasted system that are of no help in your system. You seem not to have a ballasted coil as it measured 3 ohms resistance in the primary which suggests to me it is a 12v coil. It is unfortunate that modern coils are no longer stamped with their part number on the base, often have no label on them & only come from a box with a part number on. Like you I tend to assume coils marked SW & CB are for a positive earth system. Generally coils marked + & - will be for a negative earth system, but this may not be the case. So I agree with Richard you should check the application of the coil. It is possible you have been miss-sold the coil or been misunderstood, given that the other coil you had from them was only 0.8 ohms & clearly not a normal 12v coil that you had asked for. If you search the net for discussions about using a positive earth coil in a negative earth vehicle the predominant advice is that you simply swap the LT connections over. A few brave souls will say this is not ideal but they are shouted down by people who say it works so it must be ok. Well it will work to a large degree but as I mentioned earlier you will lose the benefit of the autotransformer & it will work against the system. So that you lose 600v of HT compared to a negative earth coil in a negative earth vehicle. So this may be critical when under load, high revs, accelerating or with a lean mixture when you need all the volts you can get. Your coil only seemed to create a reliable spark across 12mm generally, I find 12v coils are are approaching a 20mm gap. So it maybe only on the cusp of running ok. Unfortunate such a large gap in air is not necessarily translated to the spark in the plug where the gas density limits conduction.

There were a lot of friendly Belgiums up at top of the circuit. In the my section of the Jones field it was 80% Dutch with that wonderful large thing stuck up into the sky. I found that a great asset as a landmark to find my way back to 'base' & reference point for visitors to find me.

Just expanding on what Richard quite correctly says. You need a negative spark from a negative earth coil. That way the back EMF of the primary, typically 300v, is added to the output of the secondary. This is because it is an autotransformer. If you have a positive earth coil & want to use it to produce a negative spark in a negative earth system then you simply reverse the SW & CB connections. This will work BUT the polarity of the primary back EMF is now opposite to that of the secondary, so the HT voltage has 300v subtracted from it. The system will still work but not as well as it might because a coil designed for positive earth used in a negative earth to get a negative spark will in fact be 600v worse off than using a negative earth coil. As regards ballasted coils it is sometimes said that because of the reduced voltage then there will be reduced wear at the points. Apart from the wear that occurs by arcing from the back EMF which the capacitor should be dealing with, the electrical wear relates principally from the amount of current switched rather than the voltage as such. Comparing a 12v ballasted system with a 12v non-ballasted system, it is true that the voltage will be less at the ballasted coil but the current in both systems will be much the same, as will be the wear on the points. The purpose of the ballasted system is to allow a boost to a cold start & increase the rate at which the primary can be magnetised at high revs.

Yes won best Post War Vehicle at W&PR 2014 & Dale Prior Memorial FV1600 prize 2012 & 2013

I think Mike is using a 12v coil as that measured about 3 ohms which seemed about right. With talk of polarity does make me wonder. Because the rotor arm edge was lovely & clean & looked as if had been losing metal. That suggests a +ve spark rather than a -ve one. Although we did consider that & when I used the LED HT voltmeter switching to reversed polarity setting it didn't seem shoot up in that setting to show that fault. But it was a rather wishy-washy set of readings. What I should have done was to connect the analogue voltmeter say on the 1Kv range attach +ve to chassis & -ve to coil output & flicked the points to confirm an upward movement. I think that is the next thing to do so as to get out of the way this possibility of a reversed HT.

Mike the precise comparison will vary with the design of each particular coil but I imagine a 6v average system & 12v average system of the same era would give broadly similar HT outputs. However I'm tempted to think 6v coil design technology did not progress much beyond WW2, whereas 12v coil design has improved. So it is possible that a WW2 6v system may give less output than a modern (high inductance secondary) 12v coil. The only way to compare is to do measurements of the HT as I did at W&P. But do you necessarily want that, given the insulation problem I mentioned earlier? I have heard of instances where electronic ignition has been fitted that has given a sharper cut off of power from the coil hence higher HT but that has caused problems because the insulation of the WW2 rotor arm could not handle the extra power. Just throwing in a googly here. Just suppose your new 12v system was giving more output than the original 6v system. Just suppose as things got nice & warm the HT output increased BUT to a point where the insulation in distributor cap or rotor arm could not handle it? As far as the 12v with ballasted system goes, the coil current will rise more rapidly at high revs than the non-ballasted system. So the magnetic saturation will be greater at higher these speeds so can give more output than the non-ballasted at these higher speeds. 90% saturation is all that is required for optimum output. Excessive current by increasing the voltage cannot increase magnetic saturation beyond the 100% saturation it was designed for, it will just produce more heat.

Mike whether it is 6v or 12v it is simply the means to create the magnetic field. With a coil designed for a particular voltage it should give adequate output. It is not necessarily beneficial to strive to increase the HT above what the system was designed to handle. Because the insulating properties of the distributor, rotor arm etc may not be able to handle a higher voltage as the insulation breaks down. Particularly true of older systems.

Mike I wouldn't worry about the suggestions to use a ballasted coil at this stage. But in reply to your points raised. 30Kv is unlikely to be achieved it is more likely to be 5-20Kv with the average conventional set up. The widely quoted advantage of a ballasted set up is to apply the full battery volts to this lower voltage coil. Interestingly FFR Land Rovers that have a ballasted system do not use this facility for start up! The reason that these vehicles do not is that the ballast resistor is for another purpose. The purpose was to overcome some of the effect of capacitance of the screened system. This was achieved by loading the primary with resistance to offset some of the effect of the inductance of the coil this reduced the time constant of the circuit. This benefit is obtained with any ignition circuit that is ballasted. A reduced time constant means that the coil can "charge up" with magnetism in a shorter time. Therefore at high revs, accelerating & under load the ballasted system will perform better. But for many ordinary sort of vehicles a ballasted system may not offer an improved performance. So you might later like to experiment to see if a ballasted system improves performance. But I think at this stage it is a complication you could do without & concentrate on getting to function in the original manner.

Thank you for sharing those Rick. I've often wondered about numbers supplied, on this handbook it suggests 250. But that may be the numbers of handbooks supplied! Sorry its difficult to read the scan, reads "IB 250" & on the second page it reads: "250 - FV1601" I don't know if you saw my post on the W&P thread but I obtained an EMER index for the early mods. I wonder does anyone over there have a comparable list of Mods, which in your case would be in EMEI (AUST)? It would be interesting to see if any EMER Mods were shared & translated over to EMEI or whether Mods were based on local problems & local solutions.

I was a bit perplexed as I could find no news items relating to this re-opening. But it seems to have been re-branded. http://www.andrew-turner.org.uk/events/opening-charm-conflict-history-and-remembrance-museum-northwood-formerly-isle-wight-military-

Just went to the W&PR web site to look for 2014 pictures & just get this: "The following directories must be writable by the web server: tmp/cache tmp/templates_c Please correct by executing: chmod 777 tmp/cache chmod 777 tmp/templates_c or the equivilent for your platform before continuing." Is it them or is it me?