philb

How many times do I have to tell you people, "No food or drinks in the Ops Room"! Our defence equipment is just not designed to survive a crisp attack. (and that's closer to the truth than you might imagine)

Very interesting, Clive. I wonder how it behaves with AC drive under compression pressures, with a fuel air mixture? Or is the answer BANG?

I think the Dorchester was the Armoured Command Vehicle, there's one at the Royal Signals museum too. The armoured cars were like a Ferret's big brother. I've not seen one in the UK but there is one in Holland.

I bet they're from your new book Clive? I just knew it would bring trouble on us.

Oh Ed, you could be my new best mate (it is optional though). I find the apparently simple but (to me) devilishly subtle operation of CI fuel injection very interesting; both the designed performance and the deterioration due to wear, fatigue, damage etc.. At risk of boring you, are you open to questions? The kind of thing I have in mind is the engine damage caused to Catweazle's (banned member but the thread might still be accessible) boat engine. It had a fuel wetted cylinder which resulted in the piston crown rim melting and the bore being badly scored. I recall that he had the fuel injection system checked as a result and no obvious fault was found with it. The suspicion was that the injector had stuck partially open but why no subsequent evidence of it and why no symptoms of trouble until the power dropped? I think he replaced the nozzle, as well as the damaged parts, and it ran fine afterwards. Phil

Steve, a timely question; I've just this evening repaired the little bracket in the picture . The slotted plate had broken so I cut a new one and welded it to the rest of the extrusion. It's a bit agricultural (for a greenhouse door actually) but was easy to do. I agree with Asciidv in that the melt is a bit runny but I've managed to contain it in the few jobs I have done. there's thread on here where I, Clive Elliot and a few others described what we had fixed with it. Like most other things, it takes a bit of practice. I believe the "magic" material is a eutectic alloy, which melts at a much lower temperature than the work-piece and then combines with some of the work-piece to make that region a eutectic alloy also - so the whole thing doesn't melt, just the region to be repaired. I've used a natural draught Propane torch for my repairs and that is plenty hot enough. It would be interesting to learn from an expert how the typical properties of the welded material compare with those of the less stratified base materials. Anyone? Phil

I design sonar systems. That usually gets the response "Oh" , then the subject quickly changes to football or the weather. Can't understand why, I find sonar fascinating. I've spent most of my career design electronic equipment for all the British Armed Forces (and a few others) and it's given me great insight to their practices, common and different. I'd like a 500 ton wooden floating MV (if you know what I mean? Napier DELTICs and two-stroke Fodens?) but my piggy bank won't stretch that far and I don't have enough pals to crew one. Anyway I have all you cyber-pals, don't I?

I wouldn't give up on that pump casting without trying Alutight/Technoweld. Many of us have successfully repaired parts that would otherwise have been scrap.

Here's a link to the valve spec http://www.radiomuseum.org/tubes/tube_t4a.html, quite a beast!

Thank you, fascinating dynamic electro-mechanical design! Similarly inspiring, in my experience, to the mechanical teleprinters - Creed 7B and the like. From the days when designers spent a good long time thinking hard before they cut metal (although the prototyping phase might have had its moments of excitement?). Does anyone here know the origins of the chain gun mechanism?

When I stripped and cleaned my engine, the paint history of the crank-case and block was 'eau de nil', red (oxide), black and, finally, a mid green - a bit like the colour of the 'reply to thread' button. Unless someone had given it a very thorough clean when it was last rebuilt, the green must have been the original colour - I don't think it was a primer for the black but it might have been. It's now back to 'eau de nil' (Dulux 'Amazon Jungle 5' actually but you'd be hard pushed to tell the difference!) and all the little leaks show up nicely.:embarrassed:

Sounds good. What did you find out?

I believe there is already UK law which limits the degree of modification allowed to a vehicle before it has to be submitted for Single Vehicle Approval and re-registered ( A process, I'm sure, that Gritineye is familiar with . Sorry, Bernard, couldn't resist it. ). So, I guess they are just intending to tighten the limits? The only real snag (technically only) is that current C&U standards apply to almost every aspect of the SVA except emissions (which are engine-age related). Having read the proposal (or whatever it is called), I couldn't see anything relating to re-registering, did I miss it? So, maybe, they will just insist on the test and updating the records following it? If the annual MoT test is a good idea, why isn't SVA for modified vehicles? I've seen some frightening examples of pre-SVA specials (kit cars in new-speak. Doh! new-speak is now old-speak, but you might know what I mean) which aren't trapped by the MoT test. Anyway, as said before, it shouldn't affect many of us.

Oh yes, as usual. Looking forward to putting a few more faces to names - if that's the right way round?

PM sent.

I'd buy a piece of piano wire and make one. It might take a few tries (and breakages) to get it right but it's not too difficult.

The show at Newark was the AEC centenary rally for which, I believe, the Dakota was organised. It passed over the site three or four times. There weren't many military vehicles there, about a dozen Matadors and a couple of Militants (including 052's lovely maroon one) but altogether there were 650 old lorries and buses! Diesel heaven.:-)

Degsy, I agree, when I said cheap I wasn't thinking of VERY cheap unbranded stuff. Tony, with the benefit of a fine filter you are free to choose. I don't suppose any of use do enough mileage to get into the coking, sticking ring problems. Without a filter I think it's best to let the crud settle.

When I bought my Matador the oil pressure was very much Like 16svt quoted but probably a bit lower still when idling hot - and that was running straight SAE40. Cutting the story short, when I stripped the engine I found the main bearings were seriously worn - the centre main had about 40thou clearance (ten times what it is supposed to be). The end bearings were a bit better so, presumably, the crankshaft was flexing in operation. Reassuringly the big ends are largely protected from abrasives by the centrifuge action of the the hollow crank-pins with lateral exit ports (nice design feature). Anyway, having rebuilt the engine it now holds 50psi hot running and about 30psi hot idle, on SAE30 - much happier. Various comments on what has been said so far: Adjusting the pressure relief valve spring probably wont help the pressure when it's hot (unless, by fluke, the valve is leaky) Detergent won't hurt as long as the engine is fairly clean to start with but it could cause trouble if there is a lot of crud to break loose and circulate. Dispersant is the devil. That causes the abrasive crud to stay in suspension and circulate for ever rather than drop to the floor of the sump. OK if you have a full flow filter - but we don't. Multi-grades are OK in principle but they will probably result in high ash deposits in the ring grooves (because of the high level of oil consumption by design - compared with modern engines) and I don't know of any multi-grades that do not also have high levels of detergent and dispersant. So, back where we started, straight SAE30, changed frequently. Because there are very few additives to lose their properties, cheap is probably as good as expensive, not that I've seen much price variation. Ducking for cover.....

I had one too. They're just about OK to run a couple of light bulbs but not much else. It is, as you say, a brush-less design and as a result the waveform is terrible and the regulation almost non-existent (loosely coupled to engine speed). It just about beats a poke in the eye in the grand order of usefulness. Don't run anything sensitive from it, the potentially very high voltage peaks could kill it. I christened mine "the worlds worst generator" and sold it.

Is the cylinder wall thick enough to take a sleeve? It might be retained by a lip, top or bottom. Charlie Brown of Deanfield Commercials makes new liners (certainly wet but maybe dry too) for AEC engines, machined from solid using one of the family of Meehanite irons, I believe.

The book has a good list of chassis numbers, going right back. I think it was supplied by John Harrington, the AEC Society historian. John seems to know it of the history of some of them too, he told me where mine had served in civilian life.

Brass plate on the near-side chassis rail just behind the cab - serial number O853xxxxx, W.D. number and overhaul record. I've not come across any direct stamps on the chassis but there might be.

Indeed, oh wise one.

Jack, when do you think you'll be able to say who can go? If the A&E contingent is a fixed number and I'm not in it, I might try to book in to the Weymouth event directly - as for previous years. Or would that upset the apple cart?