Throughout this site we use many technical terms, and given the breadth of readership our site enjoys, sometimes we are remiss and incorrectly assume everyone knows what we are referring to. For those that do not, here are some explanations of the technical terms use. |
The Warren Synchroniser
The Warren synchroniser, a device that had all but disappeared by the 1980s, was fitted between the gearbox and the propeller shaft and was operated by the clutch pedal. When the driver disconnected the gearbox from the engine, the Warren synchroniser disconnected the gearbox from the propeller shaft and the driving wheels. This allowed the gears to stop rotating completely and the gear change could be made quickly and easily. When the driver accelerated, the synchroniser resumed transmission of power to the propeller shaft and the driving wheels. A useful advantage of the Warren synchroniser was that it could be used as a freewheel device. The driver, by depressing and releasing the clutch, disconnected the drive until they accelerated and the drive connected again automatically.
After a long working life, the synchromesh components of a gearbox will become worn. This will lead to a tendency for the driver to over-ride the synchromesh and to engage the gears before they are rotating at the correct speed. This is a noisy operation and it causes excessive wear on the gear teeth. If synchromesh components do become ineffective for this reason, the only means of rectifying the situation is to replace the worn parts. If the gear changes are not rushed, however, the system may well operate satisfactorily. If it does deteriorate to the point where it becomes virtually inoperative, the driver can always resort to double declutching, rather than invest in an expensive repair to what is probably an already ageing car.
One possible danger is the addition of lubricating additives to the gearbox oil. These, while possibly reducing the effects of friction and wear on the gears and bearings, may reduce also the frictional effects on which the synchromesh system depends for its operation. If a gearbox has become noisy as a result of old age, it may be more prudent to consider a different grade of oil - or if ordinary engine oil is specified, to use a hypoid oil-than to run the risk of reducing the effectiveness of an already worn unit. If you are buying an older classic and the gearbox is quiet, but difficult to change, this may well be a sign that the seller has effected a cover-up of the true state of the gearbox. |
