Kevin Julian Posted March 20, 2023 Share Posted March 20, 2023 Hi I purchased a Humber pig last year and after some good advice and some hard work it is ready to go for its first drive. It has never been road registered so presuming it has not been driven for prolonged periods since being sold off in 1970. It came to me in fairly good shape and I've completed all of the mechanical work and checks I believe it needed. The MVT inspected it in January and were happy and after completing a V55/5 I am now waiting on the kind lovely people at the DVLA (they might read this) to send me a V5. Only thing I am unsure about is the 2 speed generator which is not charging the batteries very well or at all whilst idling. Could anyone advise how best to check the Rolls Royce B6 engine 2 speed generator. Is it working/how it should be working/should it charge at idle? And very welcome would be any tips and mechanical things to watch out for when taking a pig on the road for the first time in many years. ERM is 13BK56. Thanks Kevin Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 20, 2023 Share Posted March 20, 2023 Kevin well done very satisfying. I hope you primed the dynamo with 1/4 pint of engine oil if it has been stood idle for 3 weeks or more, this is in order to lubricate the dynamo gearbox until the engine is running & can force feed it with oil. You say it is not charging is that because the charge warning light stays on or you have measured the voltage out from the dyamo or something else? I will reply later as radio conditions are very good at the moment as it is raining heavily & I need to seize the opportunity. Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 20, 2023 Author Share Posted March 20, 2023 Hi Clive, nice to hear from you and hope you are well. I'm lost on the radio comments, another interest? I have just double checked the charge warning light as it's always been started during the day. It is coming on but very dule. I get 24v testing at idle and also at 2000rpm which doesn't seem right but i am not sure what the 2 speed means! Should i be getting a lift in voltage at idle or when driving along which I've not been able to test. Regards Kevin Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 20, 2023 Share Posted March 20, 2023 Kevin, Humber I Ton (armoured & non-armoured) have a 12A dynamo. FFW (armoured & non-armoured) have a 25A dynamo. The problem with dynamos is that below 1200 rpm-ish the output is very low. The 25A dynamo has a gearbox that comes into play at about that speed to increase the rpm of the dynamo itself. So that you can get a useful output even with the engine ticking over at 200rpm. These two-speed dynamos are force fed oil from the engine, but the gearbox will not get lubricated until the engine is running, so if not run for 3 weeks the dynamo gearbox needs to be primed with 1/4 pint of engine oil. Placed in the oil filler hole protected by a brass boss, do not pour oil into the meshed hole which is the air breather hole! The noise from the gearbox may be noisy at start up until the engine is pumping in oil. There will a change in note with a sort of whine as the gearbox clicks in at 1200 rpm. Often this oil top up is ignored either by ignorance or arrogance that it will still work as it is robust so just ignore that requirement. I have seen a few dynamo gearboxes that have failed, it will still charge but not on low revs. The EMER describes how to repair the gearbox which looks a nightmare with special tools etc better to treat it with respect out the outset. You really need the User Handbook WO Code No.12246 it is very good at explaining everything. When it was written drivers were trained to have an understanding of automotive skills & expected to do minor servicing, maintenance, fault finding etc. unlike today's handbooks that are very basic describing where the steering wheel is & how to adjust the seat belts : ( Check that your Generator Panel is complete. Unscrew the large cover at the top & out should pop a smaller cover, which should aways be carried in there. These two caps screw into the air input & output on the dynamo when wading. The trouble is that the dynamo will get very hot so the dynamo is switched to 5A output & the charge warning light will come on. This is because in normal use the cap within the cap stored at the gen panel top presses down on two microswitches that allow normal charging. So if either cap is missing or the bigger cap is not screwed down fully, it will only charge at 5A. (Radio? Yes, another hobby I have been a licensed radio amateur since 1964. I'm not much interested in talking round the world, if I do communicate with other countries I only use Morse code. My main interest is in the microwave bands, the highest band I operate on is 24GHz (wavelength of 1.2cm) Most of my daily activity is on 10GHz (3cm) using rain & snow scatter, aircraft scatter & tropospheric scatter. The heavy rain today has been particularly favourable, it all helps to get my signals from out of my valley where you can't even get a mobile phone signal) Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 21, 2023 Author Share Posted March 21, 2023 Thanks Clive, a man of many talents 'Morse code' (: I was aware of the oil top up requirement and so have been starting the truck weekly but I fear the previous owner probably did not bother; I know that not long before I bought it, it spent at least 12 months sitting out in the open untouched. I will get onto checking those covers and micro switches, seems a good place to start. would I expect to hear a noisy gearbox if there is a problem or will it have jammed? Or possibly both depending on the stage of failure! Thanks as always. Kevin Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 21, 2023 Share Posted March 21, 2023 Kevin not sure if you have a copy of the UHB, but it is an invaluable guide to daily running. https://www.greenmachinesurplus.com/humber-1-ton-4x4-armoured-pig-user-handbook-1266-p.asp If the gearbox is working you should hear a change in whine around 1000rpm as you go up & dip down on the accelerator. This will be matched with a slight shift in voltage. I would suggest using an analogue (moving coil) voltmeter for this so that you can see a trend in voltage rather than a digital voltmeter that will jump around incessantly so your brain has to keep working out whether the voltage is going up or down. I much prefer what I call a proper multimeter like an Avo 12 specifically intended for vehicular use esp 24v systems. If the gearbox has failed it will be unlikely to jam. But you will not get any useful output below 1000rpm & there will be no change in whine as there will be no speed change. As for Morse code although it is still widely used by amateurs around the world, there is an increasing use of computer generated systems where you use a keyboard & a computer generates the Morse to be turned into text by a computer the other end. No skill is required by either operator other than to type fast. To me this is a hollow achievement, a bit like taking part in a bicycle race but turning up on a motorbike & thinking you are a skilled cyclist by winning the race. 1 Quote Link to comment Share on other sites More sharing options...
David Herbert Posted March 21, 2023 Share Posted March 21, 2023 Many years ago I had an Austin Champ FFW and found the two speed generator to be an excellent reminder that if it decided to change down it was time that I did too ! I used the Champ as my first daily driver and had no real trouble with it apart from the dreadful brakes. David Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 21, 2023 Author Share Posted March 21, 2023 Thanks Clive. I do have a hand book but it does not go into enough detail about what to expect from a working generator. Thanks for detail on that, I can start fault finding now as it clearly is not doing what it should volt wise. Stethoscope on the gear box first to see if it is doing what you describe. Regards Kevin. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 21, 2023 Share Posted March 21, 2023 Kevin glad you have the UHB. You should be able to hear the change in dynamo tone in the cab as you take it through the 1000rpm ish barrier. Sometimes people wonder about priming it what happens to the extra oil? I think a B60 was reckoned to burn a pint of oil every 100 miles, so it sort of balances out. Quote Link to comment Share on other sites More sharing options...
Bob Grundy Posted March 23, 2023 Share Posted March 23, 2023 If you get really stuck I think I may have a NOS one in its wooden box. Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 23, 2023 Author Share Posted March 23, 2023 Thanks Bob, that might be good if its not working. I'm not getting excited about the thought of rebuilding the one I have. I'll be checking everything this week end and might come back to you for a price and detail on which model you have, I believe there are 3 so need to check all is compatible. Many thanks. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 23, 2023 Share Posted March 23, 2023 Kevin of the 2-speed generators ie Generator No.2 there were only two Mks, the main difference being the screw threads. Mk 1 by BTH with BSF threads Mk 2 by CAV with UNF threads I would first make very certain that is not a problem in the Gen Panel. I remember once I had a dozen panels that I tested & I think only three gave an output that was within the correct voltage range. The most difficult thing with fitting the generator was not just guiding this heavy thing in place (I used a sling around my neck to take the main weight) onto the locating spigot but getting it to line up with the oil outlet pipe going into the sump & getting the collar thread to engage. I had to use a sawn off Whitworth spanner for this. The last time I changed a generator it took over a week of intermittent work especially to get the thing in place properly. The time before that I did it over the course of a weekend show. But the time before that I drove it home, changed the generator over in 3 hours then drove it back to the show. Amazing what you can do when you are younger. When you handle a 2-speed generator you will not be able to spin it as you are fighting against the engaged gear box. If you can spin it then the gearbox is bust although it may still charge but not at low revs. If you get stuck for a Gen Panel I have a couple still in their boxes. That is not why I suggested that but they are more likely to fail than the generator! Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 23, 2023 Author Share Posted March 23, 2023 Thanks as always Clive. The spinning of the generator is a good tip and thanks also for the possible generator panel. I have to admit I thought changing the generator would be easy, clearly not the case however one of my best friends was REME for 24 years so if i leave a trail of full beer bottles up to the generator I should be sorted(: Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 24, 2023 Author Share Posted March 24, 2023 (edited) Good news today, after only 3 weeks, DVLA have accepted my application to road register the Humber. A bit of work to do checking everything is as it should be and not forgetting sorting the generator. Very happy.. Edited March 24, 2023 by Kevin Julian Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 24, 2023 Share Posted March 24, 2023 Good news Kevin that it went through swiftly. When I've been the first to register a vehicle I had to have it inspected, but back then they had inspectors, don't suppose they have those now & rely on authorised clubs. I remember when the Hornet was inspected, he wasn't at all interested in the missiles on the back. His only concern was to check the chassis plate to ensure that it hadn't been stolen. What is it registered as? Box van, rigid body or minibus? Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 24, 2023 Author Share Posted March 24, 2023 Hi Clive. It's listed as body type special purpose and number of seats 8. I did send a lot of information for them and an apology letter if i had over done it. Also sent photos to show it's condition. Plus MVT verification letter. 1 Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 24, 2023 Share Posted March 24, 2023 Sounds as if you've done the right thing Kevin. My last Pig was registered as a Minibus which I didn't like after a bit of negotiating got it changed to Box Van. Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 24, 2023 Author Share Posted March 24, 2023 Yes that part went well Clive. Not sure the generator is going so well. Started to look at it today and it doesn't seem to have the correct unit fitted. Not sure what it is but no oil feed, no caps to unscrew and no oil filler bolt. I don't think it has a gearbox either; smaller unit. Pic of the offending item attached. I think I'll have to remove it to see what it is and what else has been changed. Regards Kevin Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 24, 2023 Author Share Posted March 24, 2023 What do you think Clive, have i got this wrong? Have you seen this before. Thanks Kevin Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 24, 2023 Share Posted March 24, 2023 I think you will find that you have a Generator No.1 which is single speed (no oil feed) rated at 12A output. Easier to cope with but very rare to find. Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 24, 2023 Author Share Posted March 24, 2023 Ok Clive thanks, not so bad maybe and makes sense as it all seems to fit well and it is painted original colours. It might be outputting 12v, i would not have picked that up the way i was testing but the charge warning light is on so maybe not. Should be possible to rebuild if it's not working. Looks easier to get off! Thanks Kevin Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 24, 2023 Share Posted March 24, 2023 Kevin that looks like a Gen No.1 Mk 2/1 made by Simms, the more common one was Gen No.1 Mk 2 made by CAV that looks slightly different. Sorry to have worried you about oil, but you did say you had a two speed generator. I just assumed it had been upgraded to 25A. Often the FV1611 is mistaken for a FFW but all Pigs have three antenna bases, so it could have had wireless sets! If there is a fourth antenna base on the OS rear it is a FV1612 FFW that has been upgraded to FFR. You can test your generator without removing it. If you slacken the fan belts & energise the windings (via fuse just in case) & it will run like a motor. The real pain are the various types of Generator Panel, can be troublesome & difficut to obtain. Although some people have fitted the 2-speed generator panel successfully. Quote Link to comment Share on other sites More sharing options...
Kevin Julian Posted March 24, 2023 Author Share Posted March 24, 2023 Yes my fault Clive, i read the manual and assumed the 2 speed was standard. I'll try that test method thank you. Plenty still to learn.. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 24, 2023 Share Posted March 24, 2023 These might help. The field winding resistance should be about 15 ohms. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 24, 2023 Share Posted March 24, 2023 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.