Starter for ten
RICHARD HALL bought his first Land Rover, a Series III, just after his 18th birthday and has since owned, maintained and restored these vehicles for over 30 years now. He runs a small Land Rover repair and restoration business in Norfolk and every month he lets off steam in LRM.
STARTER motors are the unsung heroes of the Land Rover world. Big lumps of metal that sit on one side of your engine somewhere at the back of the bay, spin the powerplant into life when you turn the key or push the button, and just keep on doing that job with no maintenance, year after year. Like many of the larger mechanical components, starters are often stamped with the date of manufacture: more often than not I find vehicles 30, 40 or even 50 years old which still have the same, original and untouched starter motor that they left the factory with.
There are two basic types of starter motor you re likely to find on a Land Rover: Bendix and pre-engaged.
Four- and six-cylinder petrol engines from 1948 to the end of Series III production used the Bendix starter. This is a splendidly simple device, consisting of a big electric motor with a pinion gear at the end of the shaft, which slides up and down the shaft on a spiral groove. When the motor is energised the inertia of the heavy pinion gear causes it to move up the shaft until it engages with a ring of gear teeth on the outside of the flywheel. A one-way clutch prevents the engine from driving the starter motor if the gear sticks in engagement.
The Bendix starter was cheap to manufacture and pretty much universally used across the British car industry until the 1960s, but it had a weakness in its design. By the time the pinion reached the flywheel it was already rotating at speed. This gave the pinion and flywheel gears a hard time, and both would wear to the point where engagement became unreliable. The pinion gear would bounce out of engagement so that the starter motor just whined uselessly.
This problem would get progressively worse until the ring gear was so badly worn that the starter would no longer engage at all, and even a new starter could not be guaranteed to set things right again. To replace a ring gear the engine would have to come out. The old ring gear was split with a sharp chisel, then the new one evenly heated (either in an oven or with a ring of gas jets) to expand it, then pressed onto the flywheel while still hot. At one time just about every small village garage would have the equipment to do this job.
Another problem with the Bendix starter was that it would only work with big, coarse gear teeth. For larger, higher compression engines, and in particular diesels, it was difficult to achieve the kind of gearing needed to turn the engine over at a decent speed using a Bendix drive. The solution was the pre-engaged starter. This uses a pinion which slides back and forth in a straight line on the shaft, and is moved into engagement by a large electrical solenoid connected to a sliding fork. The solenoid also incorporates a set of electrical contacts. When, and only when, the pinion gear is fully engaged with the flywheel, the contacts are bridged to power up the motor. This design allows finer gears to be used and near enough eliminates the problem of wear in the pinion and ring gear. Pre-engaged starters were used in diesel Land Rovers right from the first diesel-engined Series I in 1957. V8 engines always had them, and the four-cylinder petrol engines went pre-engaged at the start of One Ten production.
The final refinement was the introduction of reduction gearing within the starter motor itself. This was pioneered in the United States in the late 1950s when it was found that gearing allowed the starter motor itself to be physically smaller and to draw less
current. The Lucas starter used on diesel Series vehicles and earlier 90/110 non-turbo diesels is direct drive and absolutely massive compared to the geared starter used on the later engines. Pre-engaged starters have a few more components than the Bendix variety but the heart of the design is the same – a hefty, rugged electric motor designed for a long maintenance-free life.
The item most likely to fail first is the solenoid, especially on V8s where the starter motor is tucked in close to the offside exhaust manifold and gets thoroughly cooked. If your V8 starter motor works fine when cold but sometimes appears completely dead with a hot engine, a faulty solenoid is almost certainly the cause. Many problems with starters are actually caused by dirt and corrosion on the ends of the heavy cable that connects them to the battery, or poor contact on the small spade connector that is used to energise the solenoid. Before condemning a starter motor it is worth checking all the cables and connectors thoroughly, including the battery earth cable and any straps or cables between the engine and the chassis.
I normally have a few diesel starters sitting on the shelf, recovered from old 2.5 diesels removed in favour of Tdi engines and deemed not good enough to keep or sell on. Remarkably, every four-cylinder pushrod Land Rover diesel engine from the original 2052cc Series I motor to the last of the 300Tdis shares the same bolt mounting pattern and pinion gear tooth pitch and diameter. A 300Tdi starter motor will bolt straight onto a diesel Series I. The opposite is not necessarily true; as previously noted the old Lucas starter is a big bulky device and will not fit onto any of the turbodiesels as the manifolds and turbo get in the way. The later starters usually come from one of two manufacturers: Bosch and Paris-rhone (later Valeo). Of the two I prefer the Bosch unit, which I have found to be less prone to solenoid failure than its French rival. In terms of power there is nothing to choose between the two.
Original factory starter motors are very high-quality items and usually have a long life: – the same cannot always be said of aftermarket reproduction or remanufactured units. These are often built down to a price with inferior bearings and brushgear, and shiny new starters have given me more problems over the years than grubby secondhand ones. I had a Defender 300Tdi come in for some fettling recently; it was a part-finished project, on a new galvanised chassis but with a lot of rough edges, and it came with a brand-new battery plus a jump start pack in the passenger footwell. The starter motor looked like a recent fitment but the engine barely turned over fast enough to fire it up, even when warm.
Starter motor access on some of the Land Rover range can be awkward to say the least. The Td5 notoriously has one fixing bolt which you cannot see from any angle. The Defender 200Tdi needs to have the front exhaust pipe dropped to get the starter out, and the Discovery 1 is little better. Factory-built Defender 300Tdis are much easier to deal with once the turbo intake pipe is moved out of the way. Having checked all the connections and found nothing amiss I soon had the starter motor on the floor and went rummaging around in the parts store for a replacement.
Hmm, slightly fewer starters than I thought I had. One Bosch and two Paris-rhone. I bolted the Bosch into place, reconnected the battery and turned the key. Nothing. I tried a couple more times and eventually the starter turned the engine over slowly and lazily for a few seconds until it fired. It was if anything worse than the one I had taken off. I examined the battery wiring with a critical eye and did not altogether like what I saw. The cables looked a bit undernourished and had ring terminals crimped onto the ends seemingly using an old pair of pliers. Twenty minutes later the Defender had all new battery cables, a new earth strap and a starter motor which would still have struggled to fire up a moped on a cold day. Duff battery? Not according to my voltmeter but I changed it for another, which made absolutely no difference.
I swapped the Bosch starter for one of the Paris-rhones. This had a solenoid which clicked loudly but would not power up the motor, confirming all my prejudices about these starters. The second Paris-rhone was a little better in that the motor at least turned, but the solenoid throw was too short to engage the drive gear fully with the flywheel, so it would actually start the engine about one time in five. Running out of ideas now I refitted the original starter motor. The new battery cables seemed to have made a small improvement but I still would not have trusted it to start on a cold morning. I gave up, shoved the Defender outside and set about clearing a bit of space in the workshop for a couple of gearboxes that I had just acquired.
I lifted up a tangled pile of oil cooler pipes, intercooler pipes and radiator hoses in a corner of the workshop that I hadn’t touched for months, and underneath I found precious treasure – an original Bosch starter motor which I forgotten I had. I lifted it up with trembling hands and carried it out to the Defender. This starter was my only hope – would it work, or let me down like all the others? I bolted it up, turned the key and was rewarded with the sound of a 300Tdi spinning over healthily for a couple of seconds before firing up with no bother and no glow plugs on what turned out to be the coldest day of the year so far.
I have no idea how I ended up with so many dead starter motors on the shelf. Normally the only used parts that find their way into the store are those which have been tested and judged fit for further service. I might pull the two dead Bosch starters apart just to see what has caused them to fail. Parts are available, and with my stock thoroughly depleted it would be nice to have at least one spare that I can rely on. The 27-year-old starter on my Discovery has been getting a bit lazy in the cold weather – I am crossing my fingers and hoping it holds together a while longer now that Spring is here.