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attleej

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attleej last won the day on November 8

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  1. Dear All, Years ago there was a 'scandal' in a newspaper that the MOD was, apparently, paying something like £5 for an ordinary light bulb. They even showed the packaging with the price and the D of Q. Of course, the D of Q was something like 24! John
  2. Yes indeed. I am in close touch with Peter and have discussed this problem. That is why I know that it is common to both Meteor and Merlin engines. I am very keen to share the techniques that I have developed. That is the beauty of a forum like this. John
  3. Malcolm, Not only did I have to use HSS cobalt drills I also needed to use an HSSE tap which is HSS cobalt apparently. Even so, the tap could only manage about three tappings before it lost its edge. Initially it was like going through EN1A with lots of lead! Even so, if the tap can solve the problem at £35 a time it is worth it. Most of the studs are covered in oil passing back from the valve gear. The corner studs in question are "dry". They are sealed at the bottom and there is a special washer at the top. I doubt that the temp would exceed 100 degrees C. Coatings on the stud do not appear to be successful. I was wondering about filling the void with engine oil and grinding a groove in the top washer to relieve any pressure. That way the air would be excluded so the studs would not be in a corrosive environment.. What do you think? John
  4. Malcolm, I believe that you are right in suggesting that it is a combination of stress, moisture and heat. All three. The studs other than the corner studs are running covered in oil from the rockers and do not suffer from this problem. The studs are much larger diameter where they are screwed into the crankcase 11/16 BSF or maybe bigger still. The cylinder stud nuts are torqued to 115 ft lbs. The studs are necked down so that they are quite small dia for most of their length. This means that the stretch and stress will remain constant even though the aluminium cylinder block has expanded with the heat. John
  5. Chris, If the vehicle has a B81 you need to take the revs right up to 3750 RPM but the tachometer only goes up to 2500. The engine should not be allowed to labour too much. You can get it to read true, if it is a voltmeter type, by using resistors (a voltage divider) to adjust the voltage going into the meter. I would have thought it would be easier to find another tachometer that either works or can be overhauled by one of the specialist companies. John
  6. Dear All, Further to my last, I have now looked at the Martian Gallery thread and it was pointed out that modern balancing was much better than it used to be. It was also claimed that because of this, prop shafts can be run at much higher RPM than before. So I might be wrong! It could be that all the prop shafts fitted to the Martians were slightly defective and that is why we found, from hard experience, not to exceed 30 MPH. However, given that damage to the transfer gear-box should be avoided at all costs I would still advocate a centre bearing. I think Chris is doing a great job of looking after he old girl. John
  7. Rob, My recollection is that they were steel boxes. I certainly do not remember any wooden boxes in that role on any mil vehs of the time. My recollection was of a 'union' type lock in the top middle of the side facing forwards. John
  8. Dear All, The pic of the prop shaft shows why I think that it is too long and would benefit from a centre bearing. The Martian is good for 30 MPH but any more risks ripping out the back of the transfer box as I have observed in previous posts. Well done for spotting the crack in the ball joint. The ball on the right of the two looks to be bent! Is it? What on earth has happened to the vehicle to cause that damage. John
  9. Dear All, Meteor tank engines (and later Merlins) are prone to snapping their 'corner' cylinder studs that hold the cylinder head /cylinder block onto the crankcase. The studs appear to snap in service and not just when being tightened up. It is thought to be a stress corrosion problem. The studs are an interference fit in the crank case and are very difficult to unscrew even when complete and with the possibility of have two nuts secured on the top of the stud. About 16" of leverage is required to get them to unscrew. Unfortunately, the snapped studs can leave only a 7/16" diameter stud only 3/4" high or less! The engineering solution that I have devised is to drill and tap the remains of the stud 1/2" UNF Left Hand. (Thanks to TSB for that idea). Then a left hand threaded bolt can be screwed in and the remains of the original stud will unscrew. I found that the remains of the stud unscrewed quite easily. This probably because the threaded remains of the stud 'relax' slightly. If the remains of the stud does not unscrew, the replacement stud can be turned down and threaded 1/2" UNF, LH , and screwed in place with Locktite to stop it from unscrewing when the cylinder head nuts are torqued up. I made up a range of special jigs to facilitate drilling the remains of the stud absolutely square and concentric. This is essential in case the stud will not unscrew and a turned down stud has to be resorted to. The manual makes it clear that the studs cannot be bent even slightly. Photos of the tooling can be seen on other posts of mine on the HMVF forum. John
  10. Dear All, I have made some progress on the Meteor M120 engine. I have now managed to remove the two broken cylinder studs. You cannot believe how tough the steel was. I wore out a 1/2" UNF HSSE Cobalt tap after tapping just two studs! The separate post on this subject is just to allow anyone to easily research the topic. The 'plastigauge' test shows that the main bearing clearances are within spec. After having made a jig to machine two big end shell bearings we now have a complete set of big end bearings. The last real challenge is the gudgeon pin bushes that are fully floating. The bushes are 10 thou worn out and, worse still, I have just discovered that the little end bore in the con rod has 5 thou ovality when the spec is for only 1 thou. Making the new oversize gudgeon pin bushes is easy enough. The problem is finding someone to grind the little end bore reliably and economically as I don't think my rebore shop can do that work. I will check on Monday. Does anyone know anyone who can grind con rods near to Portsmouth, Hants? John
  11. Dear All, I will miss a proper Landrover and I write this as a retired "over privileged officer". I first drove a military Landrover in about 1975 and have always had one of my own since about 1974. John
  12. Rob, This what I have. The 7/8th 26 TPI thread portion might be a bit short. I would expect to have a 1/2 BSF lock not to suit the one that Marvinthemartian has. Alternatively I could make you one. All I need to know is how long the fine threads should be. John
  13. Rob, I almost certainly have a bulkhead fitting as shown. If not, I can make one quite easily as I should have the 26 TPI die (or whatever TPI it is). Can you just confirm the O/D and length of the fine thread. The coarse end is 1/2 BSP. John
  14. Robin, I have only ever seen a nozzle similar to the one in the photo. John
  15. Dear All, The most important document is the 'work ticket' which has to be signed by an officer or Senior NCO. That is the driver's authority to take the vehicle out on the road. I think that it is either FMT 600 or 1000. The other vital doc is FMT 3 accident report form. It is a very useful doc for recording accident details. There should also be MT Drivers rule book. I cannot remember what that is called. The vehicle should also carry a user hand book and a servicing schedule. Finally, breakdown orders which would vary according to where the vehicle is operating and whether or not it was on an exercise. John.
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