philb

Jack, sorry for late response. I'll be going Friday evening.

I'll be there in (or under) my Matador

Thanks for your responses. The pump is CAV and the chap who overhauled it said that the governor was fine - I asked him that specifically because it used to "clack" when idling, funnily it doesn't seem to do that as much now. I'm stil trying to find enough spare time to make the rack position monitor, that should show what's going on. I've heard of Peter Strong and, as he's not too far away, I might take it to him after the show season. Until then I'll live with it.

Steve, Mike had a drive of my Matador today and it was a "Ah, now I see what you mean" moment. The running on was so bad compared with this that he only wanted to drive it for half a mile and then got me to take over. I'm going to try swapping the injection pump with his spare to see what difference that makes.

Brilliant!

Yes, I'd buy a shirt and a cap. Good idea.

First, try another plug (if you haven;t already) Second, try reducing the plug gap to about half what it should be. The engine should still work OK and it will be much easier for the spark to form. If it works with a small plug gap you then have to find where (if not in the plug, as Richard suggested) the juice is leaking before it gets a chance to spark.

Jack, well done for the videos, I'm starting to plan gear change and braking points! Do you know what the height of the rail bridge arch is?

Oops, I just answered the wrong question. I was talking about the spring loaded damper. I think the idling stop is also set right. Idling speed is OK and the accelerator linkage is set so that the spring is just starting to be compressed at that point. There's plenty of travel left to let the engine be stopped by raising the pedal.

Mike, yes I think so. I tried slackening it right back to make sure it wasn't holding the control rod open and that didn't make any difference.

Thanks Steve. Of the hundred or so folks that have viewed the thread, you are the only one to get the custard cream! I can only see the exhaust in the driving mirror and I didn't think it was smoking much. I'll try pulling back the maximum fuel stop a bit on the secondary adjuster to see if that affects things. My only real concern was that at some time the engine would over-speed and injure itself - without me being able to stall it. Mike did tell me that his sounded much like mine but he didn't mention the running-on issue, I'll talk to him. Meanwhile, just for fun, I'm making a sensor that fits on the back of the idling damper to measure the control rod position and show it on a meter on the dash. How's that for 2010 meets 1945?

Here's the short story: I've just re-built my 7.7 Matador engine, including having the injection pump overhauled (that may be the clue to the trouble but I'm trying not to jump to conclusions). The good news is it now has oil pressure when hot, it doesn't rumble and doesn't leak (quite as much as it did). It starts easily from cold and doesn't seem to be down on power. there's a fair bit of grey smoke when it's cold and off load but it clears quickly once it is on load. At full tilt there's a nice even stream of very faint black smoke, no sign of blue smoke at all. Idling is slow and even, with a little hunting, cold and hot. When it's cold it all works well. The problem is that once it is good and hot coming off load, like when changing up a gear, it takes ages (several seconds but it feels like ages - and much longer than it used to) for the engine to slow down. It doesn't over-speed when dipping the clutch - it just hangs on at the speed it was going at. After revving it up off load it shuts down nice and quickly. I guess the obvious thing is that the control rod is sticking but why from on load and not from off load? I've double checked the valve timing and clearances and also the injection timing by spill test in-situ - all OK. Any similar experiences? Any good ideas to force or isolate the fault (ideally without pulling the pump apart again)?

One of my first jobs was working on semiconductor replacements for valve shell and bomb fuzes. Despite the apparent ruggedness of solid state devices it was a long time before they were made as tough as the special valves that had been developed for this application. The problem was mostly that although the semiconductors were rugged, their packaging and internal wiring would not stand the acceleration of a shell firing - as the film said, around 20000g! It was a very educational and sometimes exciting experience to test them!

I witnessed an incident that may well have been due to this effect. On holiday in the USA (that's relevant for the next bit) a motorhome towing an car (unmanned, on an A frame) pulled in to the rest area we had stopped at and after no more than a minute there was a gert bang - much too loud to have been a gun, the prime candidate in that part of the world. One of the car's front tyres had exploded leaving almost no trace of it. It turned out that the car's brakes had been partially applied for many miles due to a fault in the electric brake servo which was slaved to the motorhome. It soon attracted a good crowd and despite my protests they would not keep away from the other wheels, all of which were obviously very hot. Even though I'd never heard of pyrolysis, I though there was a fair chance the others would go the same way. Nothing more happened but having seen the safety video I think we were all quite lucky. The motorhome owner thought he'd get away with just one new tyre. Oh yes - four tyres and wheels and brakes and hubs and some suspension parts, it was well cooked. At least they had somewhere to stay.

Welcome Steve. If you want copies of any of the drawings or photos from the manuals (or photos of real bits) let me know.

Welcome Lawrie, I thought you'd pop up here someday - I'm sure you'll enjoy it. Rejuvenated engine and gearbox ready to go back in now (only took five months! - mostly looking for parts), road springs next on the list. Cheers, Phil

It was sold on e-Bay about three years ago for £1200 ( I think ) by a chap near Heathrow. There was no rear bodywork and the crane was loose. I guess someone is looking after it.

I guess you're right, you've re-made a dodgy connection somewhere. Regarding temperature: The colder the wire, the higher the conductivity, the stronger the magnetic field for a given voltage - so, if anything, it would cut in at a lower voltage. You said the charge indicator light went out then back on again as the revs increased - so it was getting quite a bit more than the battery voltage across it. You also said you activated it by hand (clearing any unusual mechanical load?), so that's not it either. Most importantly, good, you're back on the road. Try fixing a modern unit that easily!

Sounds good to me too, count me in. Thanks.

I've e-mailed the scanned text but I realise there is not much in the way of description. Going on from what I said yesterday: The dynamo output is always applied to the cut-out shunt winding. When the dynamo output gets to about 25V, the shunt winding pulls the armature in and the contact is made. The load current passes through the series winding. Charging/load current just pulls the armature harder. As the dynamo slows, its output drops below that of the battery and when the reverse current through the series winding reaches about 4A its effect cancels the shunt winding field and the armature is released. If the whole system has been designed correctly, which yours should be, the dynamo voltage at idle is far lower than ~24V and the cut-out works properly. I have come across installations where the dynamo voltage does not fall low enough at idle and the cut-out does not drop out. This can leave a discharge of a few amps through the dynamo all the time the engine is idling. The point of saying this is: make sure the cut-out does drop out properly if you re-build it.

Mike, I know it's not what you are asking for but - I have the circuit diagram, description, settings and maintenance instructions if you would like them. It's the SHUNT winding (the other end from the contacts) that pulls the armature in. It looks to me as though it would be quite easy to remove that solenoid and repair/rewind it.

Mike, do you know what make/type of control gear you have, I might have details of it.

I would guess that you would be able to fix it. Get at the cut-out voltage coil terminals while the dynamo is running ( even slowly) to see if the dynamo output is being presented to the coil - it might not be. Either way track down the break in the circuit. I'd be surprised if was actually in the coil, they don't do much work and the innards are usually quite well protected from the elements. Re-winding the coil is more awkward than difficult, you probably have to remove the current winding first. As it's nice and old the connections might be screwed rather than welded - that should help. Is that more up-beat?

Mike, it sounds like the cut-out voltage coil (that brings it in) has gone and once you force the contact to close the forward charging current is enough to hold it in - it's the reverse current through that coil that kicks it out when the dynamo slows down.

Clive, where did you get the young lad from? Hold on, my incoming flack detector has just woken up. Slightly more seriously, you could also try heating it (carefully) with a hair drier (the young lad might have one) before using it. It's less messy than playing around with water - which you will inevitably do if you cool it much. Phil