Snagger

Mine either, but for something that ugly, it flies pretty well! Here's another video that shows what these things are used for. I can't imagine how low brow the audience are, but their cheering the crashes more than the successes gives a good indication. ANyway, it's still pretty impressive what abuse the vehicles seem to stand up to: http://www.youtube.com/watch?v=WwjGo3kQgMw&feature=player_embedded

Just out of curiosity, Bill, how old are you? I'm only 40, and if it's any consolation, feel much how you describe already - I find it hard to drum up the enthusiasm to go into the garage to work on my RRC, but then I am continuously putting in the legal maximums at work (not my choice). What tyres do you use on your RR? If they're oversize, then the vapourdrive would need to be a crawler for your use. Mine gets plenty of road use (or did), and very little off road, and even though it only has a standard 300Tdi turning the R380 and BW unit, I often wish for a six "cruising" gear on motorways. I might fit slightly oversize 235/75s when it's finished just because of that.

My post probably was unclear. Using a bottom PTO configuration for an overdrive would require additional new input and intermediate gears to take those tow out of mesh, and would also be tight on space laterally as the OD input and output would have to be side by side, the drive line dropping down from the gear box main shaft to the OD input shaft and then to the right to its second shaft before being routed back up to the intermediate cluster. One of those shafts would need sliding members to lock and disengage the 1-1 and step up gears, and even in 1-1 you'd be running the torque through gear sets rather than locked shafts, so loosing efficiency. It'd be much more complex and less reliable and efficient than the existing designs that use the rear PTO position.

I agree that it's the heat that is the problem on both types of unit, and that the bearings on the Fairey are pitifully small. Rather than coming up with a completely new design that achieves the same thing, creating a heat exchanger or oil cooler system would probably be more beneficial. Using the transfer box filler plug hole would be a good return line point, but then again tapping a line into the top of the case might be better so that the filler hole can still be used for level checking. The challenge would be in siting the hot oil outlet port. Maybe somewhere on the rhs of the transfer case would work? Cant't use the rear face because of the hand brake, or the front face because of the 4wd housing, and using the drain plug would be inviting disaster off road, getting ripped out on the first obstacle or in deep mud. But what about oil flow? What would work to pump the oil through the cooler? I don't know if an electric fuel pump would handle the heat and viscosity for long.

I still see no advantage - an epicyclic gear set with three planet gears will have six meshes - planet with sun and planet with ring, times three. A three lay-shaft system will also have six meshes - the front end of each lay shaft to the outer concentric output shaft and the rear end of each lay shaft to the inner main shaft. The thing is that a multi-lay shaft will be turning more mass of metal, but the radius of each piece is less. The ratios of mass/radius of all the turning parts will influence the amount of energy lost in turning all those parts, but I'd expect the epicyclic system would be more efficient and reliable as well as more compact for a given weight/strength. That's why they're used for aircraft propulsion gear boxes on turbine powered aircraft.

As long as you're sure the unions are all tight, the easy way is to open the bleed and spin the engine on the starter for a few seconds at a time, letting the starter cool 30s between each spin. After five spins, let the starter cool for five minutes, then have a few more goes. Once the engine fires, let it idle with a rag around the filter to catch the spillage while you let the bleed weep until clear of bubbles, then nip it up. If you can't get the engine to start after five cycles of five, then you have a more fundamental fuel feed problem. You might want to have a battery charger available before doing this.

You could, but it would be made more complex for it, also needing a new intermediate cluster as well as the main shaft gear (so that those two would no longer directly mesh) and complexity often means weaker.

I can't see much difference mechanically between elliptical gearing sets and a multiple lay shaft system - you have lots of bearing sets and teeth meshes sapping a similar amount of energy and generating heat, and in both cases opposing planet gears or lay shafts cancel out tangental loads on the sun gear or main shaft. One is more compact than the other, but I don't see any reason one should be stronger or more efficient than the other because they are doing exactly the same thing. As for Tanuki, I think I see the thrust of his point. The exact ratios he mentions are not hat point; what I see as the fundamental issue he raises is that the top gear selections should involve straight through drive, bypassing gear sets, so when the gear selection is giving you the least torque advantage by going high ratio, you are also minimising the gear set energy losses - it seems a shame to labour an engine with overdriving gear sets which are wasteful when straight though lock ups with higher ratio diffs would give the same end ratios far more efficiently. I hope that's what he was trying to illustrate - I don't want to put words in anyones' mouths. I think he's absolutely right - locking the gear box and a transfer box with a direct-locking 1:1 high ratio would mean the only gear sets to sap energy would be the diffs.

The thought of a doubled or trippled Fairey OD had occurred to me too (never as a physical project as I lack the skills and equipment to do it), but I came to the conclusion that the weakness of the clutch sleeve would still be there and that the heat generated by trippling the number of meshing teeth and spinning bearings would probably be similar to that of the heat generated in epicyclic gears, so you'd lose the compact design with no benefits. The better solution would seem to be a compact epicyclic design in a large housing with high oil capacity, ideally with an induced oil flow through/over heat shedding areas. The cooling fins on the Roverdrive must help to some extent, but are not huge and it's oil capacity could be made much bigger as there is plenty of room to expand the casing without altering the innards. The way in which the Roverdrive shares its oil with the transfer box, using a finned bottom cover must also help, but a pumped oil cooler would be even better. Maybe an electric fuel pump with a length of coiled copper brake line would be effective? Now, what would be a useful overdrive is one which would also function as an underdrive (ie, low, 1:1 and high) - I could really use that on my 109, giving huge flexibility for low speed and motorway work. I know someone was looking at it, but they shelved the idea because of the economy. Maybe if they considered how many more people could fit big tyres tot heir LRs, or cheap 3.54 diffs to Series vehicles but currently can't because they'd be overgeared, using the underdrive feature for town driving and accelerating and the high function like on current overdrives for long range cruising, so that people like me can have their cake and eat it, then there might be a market for such a unit.

I'm working all weekend again, Mike - I might have come along otherwise. The difficulty in sourcing a revolving tow ball hitch is what makes me curious as to why they don't use NATO hitches, given that the latter will allow 360 degree linear rotation and 90 degree articulation in all axis, and without putting any pressure on the release mechanism or creating any friction or significant wear in the hitch. I presume it mush be a legal rather than practical issue. I can see the limits of a standard hitch easily being exceeded crossing a moderate ridge or gulley, while a NATO hitch would barely notice it...

This is great work, Mike. I fancy doing longer trips in the distant future and was contemplating making up an exped trailer with top mounted tent similar to those in your links, using my Sankey as a base, but this is much more impressive! It will limit the vehicle off road while towing, but of course will lighten the vehicle when base cam is set up, and it looks like a very comfortable way of living out. One question: all the off road trailers and caravans seem to use standard hitches, while NATO hitches would seem at face value a much tougher, more secure and articulate solution. There must be a reason for using the standard hitch - care to share?

I sympathise with you and understand your dilemma, but sender units are notoriously unreliable when not sourced as a genuine part, and if the 200Tdi sender is giving the same indications as the new sender, then I think it's highly likely the new sender is inaccurate or even mis-labelled. Similar discussions in other threads have suggested that most senders marketed by non-franchised LR specialists as ideal for Tdi retrofits don't work. Before you spend a lot of time and effort chasing a list of faults that probably don't exist, try a Genuine Parts petrol engine sender for the year of your vehicle. It shouldn't cost the Earth, and will be much cheaper than replacing thermostats, gauges, radiators, water pumps and so on...

You stated the sender was sourced from the net, and it has already been pointed out that non-genuine senders tend to be faulty...

I am no expert on vehicle dynamics, and while I agree that power distributions and suspension design have great effects, I don't think your friend is entirely right. I suspect that the RRC, Discovery and Defender models are all permanent 4wd to reduce the strain on the none-too-strong LR standard axles, splitting the torque over the pair instead of loading one. This would also be supported by the early 90/110 having part time 4wd and having optional FWH - their suspension was coils all round, and I suspect that LR only gave this option because these early proto-Defenders had low enough torque from their 2.25 engines that they wouldn't blow the rear transmissions in 2wd. Handling would be improved by 4wd, especially on wet or icy roads, but I don't think 2wd on coils would have been a serious issue. Just a though on your plan of having the front radius arms horizontal - in addition to needing very low mountings, they will also lose the anti-dive characteristics of inclined radius arms. If you compare how much a LR coiler dives under braking to a leafer, it's a pretty big difference. This anti-dive is achieved by having the radius arms drop down at an angle parallel to the angle drawn from the CoG to the front tyre contact areas. This anti-dive characteristic is not only more comfortable, but presses the tyres harder into the road surface, imcreasing braking efficiency and safety. You'd be losing a lot but levelling the radius arms.

Actually, they are the same except for the drilling of the filler holes, and the inner housings (chromed chalices) are identical. The castor is set by the bolt hole positions on the main axle case flanges. The brake back plates are handed, though, and snail cam orientation is important for the reasons already given.

The Defender and Discovery senders are incompatible with SII or SIII gauges. Why not follow the advice given and fit the correct sender for the gauge you have?

Your problem is mixing a 4-disc brake master cylinder with drum brake slaves - disc brake master cylinders produce higher pressure but lower volume than Series masters, and are incompatible. You need the correct SIII pedal box, servo and master, and be warned that there are two different masters for dual line servo assisted brakes, one for SWB and one for LWB. As mentioned, that unsupported Tee is poor - it could result in vibration induced fatigue cracking of the pipes or unions, resulting in brake failure. You would have been better off using a blanking fitting (as used on brake callipers to blank of cross-drillings) in one of the MC ports and a single brake line to the other. I don't wish to sound unpleasant, but when it comes to braking, steering and suspension work, people should not be touching them unless they really understand what they're getting involved in. Replacing like for like is one thing, but when the inexperienced and untrained start swapping non-specification second hand parts over to save costs, they are risking their lives and the lives of other road users to save money, and that is a very dangerous attitude.

The problem with electric power steering assistance to the steering column is that it puts huge strain on the standard steering box and relay (as mentioned earlier, those relays can twist or shear relatively easily if overloaded), whereas the hydraulic options (whether a full PAS replacement from another vehicle or the strap-on ram kit) provides assistance after the relay or replaces it completely, so such shears are impossible. If you want to fit discs, a wider axle and CV joints, why not fit coiler axles? I have done it to my 109, retaining leaf springs. The front axle saddles have to be a bit taller to allow the track rod to clear the springs, but by using 1-ton shackles and re-orienting the spring angle, ot by using a 1-ton chassis like me, the loss of ride height can be regained. The one issue I seemed to have after fitting coiler axles was the tendency of the front prop UJ yolks to hit the rhs engine mount under heavy braking. This is because of the combination of the higher diff pinion position (inclined, rather than horizontal like SII/SIII axles) and the lower engine bracket for the Defender TD/Tdi engines. By fabricating a higher arched engine mount, the clearance issue has been resolved and the axle wrap control ideas I was investigating have proven unnecessary. It's all documented on the axle section of my blog.

It's very low quality hose and splits all the time. I don't think it tolerates the heat very well, and doesn't seem to like diesel either, despite being specifically made for it. As the others said, get a roll of hose from Halfords - there's no need to replace the banjos or other parts of the spill sstem, and you don't even need to undo the bolts; just pull the old hoses off the banjos and slip the new hose on - it's simple push-fit with no barbs.

I vaguely recall the post, Bill. It was similar to what I had in mind using a P38 box, which not only fits outboard of the chassis but whose bolt holes are conveniently spaced to fit above and below the chassis rail, needing just some reinforcing plates and anti-crush tubes to clamp to the chassis with no chassis alteration. The P38 box is also more robust and reliable than the 4-bolt Adwest type used on the Defender/Discovery/RRC, and has lighter feel, and may even be cheaper froma scrappy because they are less in demand, being more reliable.

There is another way, which is to fit the electric steering from a modern car to the steering column of the SII/SIII, but that could have certification implications because of the cutting and welding of the inner column (even though the worm gear at the bottom is welded on). To be honest, neither the electric or ram systems take my fancy - they leave the comparatively vague and low geared original system in place, while the Defender/P38 system gives much tighter feel and higher gearing as well as reduced effort.

I think that it's a real case of apples and oranges. They're very different systems with very different characteristics, and as such are used in different applications. IS is certainly more comfortable and compliant at speed, with much better stability. Live beam is better where ground clearance is an issue. The thing is, you won't be doing high speed, needing the stability of IS, if ground clearance is an issue, and so LB will do the job in those circumstances amply. Likewise, most vehicles that drive at high speed won't need the ground clearance of LB, so again, they don't need a compromise system, like the buggy in the photos or Dakar racers - they don't rock crawl or cross ditches and bomb holes. LR have been ingenious in their use of cross-linked IS on the new models, which gives the best of both words - the only compromises are complexity and cost (the former being a major consideration for use in remote locations). If you can come up with a system that gives the advantages of IS and LB without the complexity of cross linking, I think you'll soon be a rich man!

Absolutely brilliant!

I guess not - I didn't consider the rotation of the wheel position on the hub, lining the wheel nut lobes up with the drive flange bolts...

No, they won't. The 200 Defender 110 axles are identical to the earlier 110.