Lucky escape
IF you spend any time restoring old vehicles for money, one of the lessons you learn the hard way is that the last 20 per cent of the job takes around 80 per cent of the time. This 80/20 split is known as Pareto’s Law and turns up in many different areas of life: for example, many businesses get 80 per cent of their income from 20 per cent of their customers. In Land Rover restoration, that last 20 per cent of the job is all about detail: ensuring cables and pipes are properly routed and securely fastened, adjusting hinges and latches so that the doors shut properly, hanging the exhaust system properly so that it does not rattle against the chassis, centring the steering and making sure the tracking is spot-on, and so forth.
The problem with this kind of work is that the customer doesn’t see it. Fresh paint and upholstery are easy to appreciate, likewise a smartly painted engine in a clean, tidy bay.
But doors which don’t fly open on corners are taken for granted, even though the restorer might need to spend a couple of hours adjusting body mounts and inserting spacing shims to achieve a good fit. As a result I see quite a few freshly restored vehicles which have been brought to me because the driving experience does not deliver on what the appearance promises.
A good example was the early Series III which limped into the Norfolk Garage a couple of weeks ago, having been delivered by transporter. To be fair it had not been subjected to a full restoration, but had been extensively smartened up with fresh paint, new seats and canvas, and a chunky set of tyres on Wolf rims. It was structurally solid and everyone who saw it said “Ooh, lovely”. But after putting about a thousand miles on it the owner had thoroughly fallen out of love with his new Land Rover. He had a couple of long journeys planned for it, and it was up to me to make it fit for the job.
The obvious starting point was the engine. This was the usually dependable 300Tdi turbodiesel from a Discovery. The vehicle had started life with a six-cylinder petrol engine, which meant that the gearbox sat further back in the chassis than on the far more common four-cylinder vehicles. As a result, whoever had carried out the conversion had been able to fit a five-speed Defender LT77 gearbox, mated to the Series transfer box with an adapter plate. I have been asked a few times about five-speed conversions in Series vehicles: the main problem is that even the shortest LT77 is a good few inches longer than the Series gearbox, so you run out of room at the front for the radiator, intercooler and pipework unless you move the transmission back in the chassis or fit a later-style flat front which not everyone wants. On a six there is just enough space to squeeze everything in behind the standard Series radiator panel.
The conversion had been very neatly done some years earlier: the only gripe I had with it was that the engine was slightly skewed in the chassis. When fitting a 300Tdi to a Series you need to trim a bit off the left-hand engine mount and then fabricate the chassis brackets so that the mount is hard up against the chassis rail: the engine on a Defender sits a bit closer to the chassis centreline than on a Series, so you can’t just copy the Defender chassis brackets. I have seen a few 300Tdi conversions in Series vehicles and most of them have the engine out of line. It doesn’t seem to cause any major mechanical problems but it looks odd.
As part of the renovation the 300Tdi lump had been treated to a new head gasket but there was something badly wrong somewhere. It idled very roughly with clouds of light-coloured smoke, sounded as though it was off a cylinder or two at higher speeds, and wouldn’t pull the skin off the proverbial rice pudding. Valve clearances seemed to be a good starting point, so I undid the three rocker cover nuts and one of them came out with the rocker shaft mounting stud still attached to it. The rocker shaft on a 300Tdi is held down with three nuts on studs and two bolts, all of which screw into the aluminium cylinder head. The errant stud had stripped its thread, probably because of over-tightening. I keep a good selection of thread repair inserts on the shelf so it took very little time to remove the valve gear, drill and tap the head and fit an insert.
Tdi engines have little caps on top of the valve stems to reduce wear on the tips of the rocker arms. These have a habit of punching through, leaving massive valve clearances which will make the engine run rough and sound horrible. I was expecting to find a couple of damaged caps but they were all fine. I refitted the valve gear, started checking valve clearances and found that all eight adjusters had been screwed down so tight that they were holding the valves slightly open. There should be a clearance of 0.2 mm between the valve rocker and the cap in the off cam position. Sometimes you find a piece of workmanship on a vehicle for which there is no rational explanation and this was one of those moments. With the clearances restored to factory settings I turned the key, the engine fired up and settled down to a happy, smooth, smoke-free idle.
The next job was to look at the steering. The owner had originally approached me to enquire about power-steering conversions. The steering on a Series Land Rover is very low-geared and the wheel is huge: I take the view that if the vehicle feels almost undrivable without steering assistance, something is probably wrong with the steering system. And so it proved. I detached the steering rods so that I could check each part of the system separately and quickly narrowed the problem down to a very stiff steering relay.
This component is bolted through the chassis just behind the radiator panel and transmits the steering operation through 90 degrees. It also performs a damping function to help cushion shocks being transmitted through the front wheels in off-road conditions. It should be filled with EP90 gear oil but tends to be ignored until it wears out or seizes. New relays are usually supplied dry and not everyone realises they need to be filled with oil before use. Lubrication is tricky – there are four small bolts holding down the top plate, of which two need to be removed. Oil is then trickled into one of the bolt holes while air escapes from the other. It helps to remove the top steering arm but this can be a challenge in itself. This steering relay was bone-dry. I was concerned that the oil I fed into it might just run straight out past the seal at the bottom of the shaft, but fortunately it stayed put.
While I had the steering in bits I freed off the track-rod ends so that I could adjust the tracking. With everything back together I took the vehicle for a short road test and was pleased to find that the steering felt exactly as I would expect, with good self-centring action and no tendency to wander around on bumpy roads. The engine shovelled out black smoke under load. I suspected someone had wound up the full power fuelling so I turned it back down and the smoke disappeared, without any noticeable effect on performance.
Now that I had a driveable Land Rover I set about giving it a full service, The owner had no record of the timing belt having been changed, so I suggested it might be a good idea to do so. There is a long and complicated history around 300Tdi timing belts, with several design modifications to stop the front edge of the belt wearing against the tensioner. A belt replacement turned out to be a good call – the camshaft oil seal had failed and the belt was soaked in engine oil. The belt itself ran true on the pulleys with no tendency to creep forwards when the engine was turned by hand. While changing the belt I found another stripped thread, this time for the stud which attaches the serpentine belt tensioner to the timing case. Thread insert to the rescue again.
There were a few more niggles to sort out, starting with a non-functional temperature gauge. The 300Tdi has a rather small gauge sender and I am not aware of a version of this sender whose resistance curve matches the Series temperature gauge. I tried drilling and tapping a spare thermostat housing to take a Series sender but the metal around the sender was wafer-thin in a couple of places and I feared it might crack. I eventually found a threaded adapter to take a Series sender, which screwed into the top of the thermostat housing in place of the plastic plug used for bleeding the cooling system. The sender is the correct side of the thermostat to give an accurate reading, so this solution will work just fine unless the coolant drops so low that it no longer reaches the top of the engine. I suspect that by the time that happened the temperature gauge would have been in the red for a little while.
The heater plugs were fed via a standard Defender/discovery timer relay which appeared not to be working. On investigation I found that most of the wires on the relay plug were wrongly connected. Unhelpfully, on later vehicles Land Rover made most of the wires black to make it harder to hot-wire the vehicle via the relay plug. Luckily I had a 200Tdi plug and harness and was able to use that to work out which wire did what.
Just about the last job on the list was to investigate the uncooperative gearchange. The LT77 gearbox normally has a fairly strong spring-loaded detent to prevent accidental selection of reverse gear. On this vehicle it was almost impossible to find first gear as the detent was so weak. The detent consists of a sprung plunger in a housing bolted to the right-hand side of the gearlever extension housing, just below the gearlever itself. It is adjusted in two ways: a screw and locknut to vary the tension on the plunger, and shims of varying thicknesses between the detent assembly and the gearbox. I removed the detent assembly and the plunger action felt fine, so I removed a couple of shims, bolted the detent back into place and found that it now worked as it should.
All I had left to do was to refit the transmission tunnel cover. On a six-cylinder Series this fits on top of the floor panels which makes life easier than the
four-cylinder vehicles, where the floor panels overlap the tunnel cover and need to come out before the cover can be removed. As so often, the tunnel securing screws had been replaced with whatever came to hand, in this case some rather long, large self-tappers with pointed ends. As I fitted the last screw there was a flash of big electrical sparks. I hastily unscrewed it and removed the tunnel again to investigate.
Six-cylinder Series vehicles have the battery under the passenger seat. The main battery cable normally runs along the nearside of the vehicle to the starter motor. This vehicle had been fitted with a battery isolator switch on the bulkhead within reach of the driver, so the battery cable had been routed along the right-hand side of the gearbox and neatly secured with P-clips, directly in line with one of the tunnel securing screws. When I refitted the screw it went straight through the cable insulation creating a dead short. There were two holes in the insulation, so I wasn’t the first person to have discovered that problem. You would have thought that the cable would have been rerouted after it happened the first time. The owner is lucky that the vehicle didn’t go up in flames.
The owner came to collect the vehicle and I suggested a short test drive. He was delighted with the way it drove and set off happily on a five-hour journey.
Half an hour later the phone rang and it was the call I always dread: the vehicle had broken down after leaving my workshop. The oil pressure light had started flickering and was now on permanently. He had checked the oil level and it was fine. What else could I suggest might be awry?
There were two possible options. One was that the switch for the oil pressure light had failed. Whenever someone posts on Facebook that their oil pressure light will not go out the advice is always the same: change the pressure switch first.
These switches are cheap (around £5) and take only a couple of minutes to change, but they most commonly fail open circuit (ie, no warning light at all) so I was not hugely optimistic. However, sudden total loss of oil pressure on a 300Tdi is rare: most of the occurrences I have heard of are caused by excessive wear in the oil pump drive dogs at the front of the crankshaft. I had checked these while changing the timing belt and they had looked fine.
So I threw a few tools and a pressure switch into the Discovery and drove out to the stranded Series III. In no time at all I had changed the switch. The oil pressure light went out as soon as the engine started and stayed out, so I told the owner to continue his journey, keep a close watch on the light and stop if it came on again.
I had a message that evening to say that the vehicle had got home without missing a beat. Someone that lucky really ought to be buying lottery tickets.