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paulbrook

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Posts posted by paulbrook

  1. I seriously would not bother with the rule of 12 but the idea is that you imagine a line across the engine between No3 and No4 cylinders and when one valve on one side of the line is right up (its a sidevalve remember) then you adjust the corresponding valve at the other end of the engine: so adjust valve No 12 when No1 is right up, 11 when 2 is right up etc etc etc.

     

    I always forget where I am up to and besides, working out exactly when a valve is at its highest point can be tricky - not too bad on an OHV engine where you can see clearly, but a bit of a guess when you are peering into a gloomy oily valve chest hidden behind a manifold.

     

    Go for TDC (compression) - much easier and most likely much more effective!

  2. I have never done them on a WC but I have a Kew-built Dodge Fire Engine with the same (virtually) engine. The manual says 14 thou for both inlet and exhaust cold and that's what mine were set at. If you fancy doing it running you might want to invest in some asbestos wrists as it will be a bit warm. Actually I am not sure it can be done running as things will be moving a bit too much to get a spanner on.

     

    I also recall 3 hands are needed - two for the two spanners (the locknut and the adjusting nut) and one for the feeler gauge, unless, of course, the military engines are wildly different from the civvy ones. For normal humans expect to be bending down picking the feeler gauge off the deck a few times!

     

    The perceived wisdom with these things is a rule of 12 (adjust valve 1 when valve 12 is fully open etc) but with a flathead (sidevalve) things are much easier. Find TDC on the compression stroke for any cylinder (although No1 is a good place to start). You know it is at the top of the compression stroke when the piston is at the top (either check the timing mark or gently pop a wire into the plug hole) and the rotor arm will be pointing at the pluglead segment in the distributor cap corresponding to that particular cylinder.

     

    At that point both inlet and exhaust valves for that cylinder are both fully closed and so you can do both clearances for that cylinder. Turn the engine through one complete turn and move on to the next cylinder in the firing order. A quick check of piston and rotor just to make sure that you got it right and then another two valves etc etc etc.

     

    If any clearances are huge suspect a stuck valve.

  3. The fuel would have to be seriously rotten to cause the symptoms described. Take the union off the carb and pump some fuel into a container. If it is the colour of tea (without the milk) and if it stinks (a sickly smell) then it may be off, but even then the truck would just pop and bang and would probably run better lean (ie no choke) than rich (choke on). Remember that this was an engine that would run on pool petrol.

     

    That said the best approach has already been mentioned, and that is to strip it all and clean I out; in particula look for condensation in the bottom of the float chamber - a mere droplet of water would cause the symptoms described. For good measure undo the feed from the tank to the pump, stick an airline with a few PSI pressure on it and blow that al back into the tank too.

  4. Indeed.

     

    Just for the record the Dyson 50ton Tank Transporter trailer that resides there (and we have been unable to take possession of since the museum closed first time around) belongs to one of my clients, who purchased it, a second trailer, and an Antar Mk3a from Mr David Arnold a long time ago.

     

    Should this trailer be offered for sale or attempts made to dispose of it in any way I would be grateful for a heads up. Many thanks.

  5. OK this was a bit extreme but the No1 did the right thing (at first) by chucking it back off when it did not go on straight first time (rather than attempting to manoeuvre on the trailer bed). I think the load had a fault but even so it was a bit scary.

     

    Interestingly given, as some have said, the abilities of your average tank the only way you could get a Chieftain up onto a 50t trailer was flat out in lowest gear and that meant that sometimes they would come on with a bit of a bang. Plus they overhung each side. God help you if you were anywhere near the back end of the tank as the exhaust noise was excruciatingly painful as it revved to the max.

  6. During the trials all three contenders were run against the in-service MK, and all were better off road loaded (in a range of terrains), part loaded and empty, and that was even though the replacements had more road-friendly tyres.

     

    The Leyland Daf, being permanent 4wd, was particularly foolproof. The best of the lot though was the Volvo, with excellent gearing, near perfect weight distribution and the turning circle of a London taxi.

  7. Urban myth

     

    The Leyland was a much better truck and much better suited to the task set than either the truck it replaced (in part) or the AWD (bedford) contender in the trial.

     

    Anyone who says different probably preferred black and white telly, telephones with dials, rickets and the ability to tell racist jokes without censure. Plus they probably never had to use one in anger. Not that the old MK was a bad truck - it wasn't. But the Leyland was streets ahead when it was tested by many many users.

  8. If it was a Leyland prototype it would have been a Scammell (if that makes any sense....) as the Leyland badge was only fitted when the MMLC went into production (all the prototypes and pre-production equipments were Scammell).

     

    I ran the prototype/pre-production fleet in the DROPS Trials Team - this was not one of ours - at least not in this configuration. The chassis could well be a Foden MMLC though which was very similar to the Scammell (Leyland) offering, but fitted with the larger wheels.

  9. If the bolt does not actually pass through the water jacket and water is getting into the bolt hole then it must be coming from somewhere - either leaking along between the water holes and the bolt hole in the head gasket or through a small crack in the cylinder head between the water jacket and the bolt hole.

     

    Now all that sounds a bit drastic, but if it really is the tiniest of weeps and only the occasional bubble then it may be prudent to leave well alone.

     

    A check of the head bolt torque settings might be worth doing, but only with a great deal of care I think. I would be tempted to add some K Seal to the coolant and keep an eye on things for now. The alternative is head off and some prudent crack/non destructive testing.

     

    Oh and it is worth considering if rainwater is running onto the top of the engine somehow and collecting in the recess round the bolt - when the engine gets hot it boils off as you describe!

  10. I am not sure if this has been posted before - if it has I apologise. I was sent this link earlier, and it is well worth having a look through. Amazing artwork from a man who probably had a lot more to think about than capturing with pen and brush the things going on around him.

     

    http://changipowart.com/

     

    Very humbling indeed.

  11. Both GP and ISO racks had the same carrying capacity - 15t. Remember though that the GP rack was single use - a bit like a big pallet; it was a throwaway item which once delivered to the gun line would not be used again which explains the different construction.

     

    As far as I recall there was no specific MLRS rack. MLRS rockets came in their own pod which could be loaded to either rack type.

  12. There are/were 2 types of rack: GP and ISO. They are identical except that the ISO rack has twistlocks to secure a container. At the rear these twistlocks are mounted on short fold-out arms because the rack itself being ISO and having the A frame at the front is too short for a full length 20' box.

     

    Both are capable of carrying an evenly distributed 15t load (evenly distributed side to side as well as end to end).

  13. Datadawg - The debate is specifically about 432 but the principles are much the same.

     

    Fox at just under 7 tons and relatively small in relation to the size of the loadbed (and therefore allowing a decent tie-down scheme) is likely to have a CofG of 1.2m or thereabouts (just over half the overall height) will impose an overturning moment broadly similar to twice the weight at half the height of C of G (which is the case for 155mm ULC) and would therefore in my considered opinion be an acceptable load.

     

    Saracen at 11 tons and a similar height CofG to the Fox would, however impose a much greater overturning moment. Not as bad as a 432, but still outside the design parameters.

     

    Both loads, however, would be unlikely to cause any one axle to be overloaded depending on US rules and regulations. With that in mind I leave you to make your own determination!

     

    As well as the road situation it must also be remembered that the flatrack and load have to be hoisted on and off the vehicle, during which the potential for issues is much magnified, yet seems to have been forgotten thus far in this exchange. The idea of marginal loads being loaded or unloaded in the vicinity of the general public by untrained and unqualified operators makes me shudder!

  14. This is nothing to do with the current debate but it may be of interest to some as technically it is not a truck.

     

    It was procured as a weapon system. MMLC looks like a truck and drives like a truck but it was designed and built for the sole purpose of delivering vast quantities of artillery ammunition and engineer stores (mostly anti tank bar mines) to support 1 (Br) Corps hold the advancing Soviet army until either a diplomatic solution was found or tactical nuclear weapons were used. In the early days MMLC and IMMLC were even considered as a candidate for C vehicle status (ie plant) because of the very limited role envisaged. It is not and was never a GS truck.

     

    The design brief was very narrow indeed and a difficult one to achieve, a delicate balance (if you pardon the expression) of a determination by the MOD centre to comply with construction and use whilst a the same time meeting the ammunition throughput requirements; hence the caution consistently expressed by myself regarding its use as a GS vehicle. As I have said before, even putting it on the next sized tyres (insisted upon by MOD in order to improve the ground clearance to the levels demanded by the medium mobility design specification) caused the first-off model out on its maiden voyage to capsize in front of the assembled good and great at RARDE - and that was just driving in a lazy circle in front of them.

     

    That's said it was quite clear that the vehicles could be used for other purposes, but in this regard, and noting the above, instead of MT staffs working it out for themselves in the time honoured fashion with trim sheets and a decent dose of common sense, each and every load and its associated restraint scheme for DROPS had to be designed, developed, if necessary trialled, then published in JSP71.

     

    It is further worth noting that the flatracks were designed and built to be used once for a one-shot delivery of said ammunition, from the depots, through the DROP system, to the guns/launchers/minelayers, where, like pallets, they would simply be abandoned. As such they were not subjected to any sort of reliability, battlefield day of life-cycle testing, and neither were they expected to be used again and again in peacetime except in certain controlled training circumstances. I rather like the one-way street of racks in the event of war because as presumably the abandoned empty racks would double up as decent obstacles to thwart the progress of the advance of 3rd Shock Army.

     

    All of this design, development and procurement was a quarter of a century ago. Since then, of course, elements of the DROP system have been used extensively all over the place and many have suffered the ravages of time; at times over the years the fleet has even been subject to "track mileage" constraints. During my last few years in service (including my time as the chap responsible for the training of every single DROPS operator and instructor across the 3 services) the fleet were routinely grounded for one reason or another, including lots of cracking of various structural components.

     

    So you will forgive my caution I am sure. I should, of course, do what I said I would do and shut up, but having lived DROPS quite literally from pre-cradle to pretty much grave I just like to ensure that history and hard won experience is not lost.

  15. Having said I will bow out I will just have a small addendum to the simple GVW issues outlined already, based on the Army assessment as I recall it:

     

    Stability - both on the road and loading - are seriously compromised by the maximum payload with a CofG much higher than the design 0.5 m which was the case for 155mm ULC or MLRS SPL (which were the loads for which the system was designed and built). These things do not just lift an inside wheel, they fall over, very suddenly, very dramatically and very comprehensively, and sadly even the best drivers bum is no indication that the point of no return is about to be reached.

     

    Load restraint. Even at the capacities advised in the HSE guidance securing a 432 properly onto a GS FR is problematic. Lashing points, such as they are, are only rated at 1.5t (and even then there is no certification paperwork). The dimensions also make it difficult to ensure that lashings are set at less than 60 degrees. Because of the additional stresses imposed by loading and unloading JSP71 (The Joint Service Loading and Restraint authority) specified that the standard restraint rules for DROPS were increased by a factor of 2 - that is to say that the restraint system should be capable of holding 2xweigh forwards, 1xweight sideways and 1.5x weight rearwards.

     

    I am sure that there are other issues, such as second axle loading, but the above were the reasons why it never carried 423 in service.

     

    And now, I promise, I will shut up!!

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