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Ballarat Tramways road roller Jelbart

The following section (Roller Requisites) is a reproduction of an article from the July 1998 edition of Running Journal (our regular newsletter). It is a light hearted account of the starting procedure for the Jelbart Road Roller, based on the instructions of Doug Wiseman, who was the backup driver for this machine at the closing of the Ballarat Tramways in 1971.

Roller Requisites


Ballarat road roller at Lake Wendouree. Photograph Graeme Breydon

Ballarat road roller at Lake Wendouree. Photograph Graeme Breydon.

In the last Running Journal one of the items covered the emergence of the Jelbart Roller from the depths of the bus shed. Readers may be interested in what it takes to get this marvelous machine going — it isn’t just a case of turning an ignition key or putting the trolley pole on the wire.

First, check the water level in the tank — it should be a couple of inches below the top of the tank. This acts as a heat reservoir for the engine, as it relies on natural circulation of the water through the engine block to keep the engine cool in the absence of both a water pump and radiator.

Put leaded super petrol in the fuel tank (not half leaded) to start — once it has warmed up we switch to power kerosene (unavailable these days) or a diesel petrol mix. Fill the priming bottle with super. Open up all the oil lines taps to ensure that all the bearing surfaces are lubricated and check the oil level in the reservoir.

Put the drive belt through the upper drive pulleys, but not on the fly wheel pulley (yet), retard the spark, adjust throttle at random, open the fuel taps and close the choke (or is it choke the close?). The next step is one of the most important steps to a successful start of this machine — locate one well-muscled fearless assistant and station on the left-hand side of the roller.

Open the decompression valve a couple of turns, and get the fearless assistant to slowly turn the flywheel over until the (one and only) piston is at maximum compression (this is a good move as he can’t see that you’re not doing work to help him). Once this has been done, prime the decompression valve with petrol from the priming bottle as the fearless assistant slowly rotates the flywheel back — if you’re doing it right, you get a really good slurpy sucking sound from the piston. Prime the governor fuel cutoff tap with some more petrol and ignore the general smell of liberal amounts of vaporising fuel.

Coordinating with the fearless assistant in the time-honoured manner (1-2-3-Go), turn the flywheel over as quickly as possible, grabbing the spokes by hand and spinning it up. After doing this for about 30 seconds, realise that it’s not going to start. Select appropriate words from extensive Anglo-Saxon vocabulary and apply to construction and operation of the machine, and wonder if an expletive deleted big starter motor can be fitted. Wipe hand across face to liberally cover with mixture of oil, petrol and grease, and persuade fearless assistant that it really isn’t that hard to start. Re-prime engine with fuel, fiddle with choke, throttle and spark settings at random, and fail to start engine another 11 times.

On the thirteenth attempt, decide this is definitely going to be the last attempt today. Amazingly, the engine fires, so furiously close decompression valve, advance spark and race around to driving position, Then start twiddling the throttle and adjusting the governor setting until the engine is firing about every four or five strokes, which means that it should be ticking over fairly smoothly. Once it has warmed up a bit after a minute or so, open the choke.

Then slip the drive belt onto the flywheel pulley taking care not to fall into the spinning flywheel, and we’re ready to go rolling (but not rocking). The final two steps before venturing out into the big wide world are to thank the fearless assistant and take a mental note to make an appointment with your chiropractor and/or masseur on Monday.

Just a couple of notes to finish up — don’t let it run out of fuel before you get it back in the shed as it’s a right b-----d to restart when hot. The other thing is that with judicious adjustment of various controls, it is possible to produce a backfire so explosive it will deafen everyone within fifty feet, lift the roofing iron off the bus shed and have the police come round from Kilmore asking who is firing off shells with a six inch naval cannon.

Driving the Roller

There are several main driving controls to operate the roller.

On the right of the driving position, there is a single lever for the clutch and brake which is fitted with a crescent ratchet. When pulled in one direction, it tensions the drive belt against the pulley that drives the gearbox. In the other direction, it releases the drive belt and applies the normal service brake for the roller.

To the lower left is the quadrant lever for operating the parking brake — this should not be used for bringing the roller to a stop, but only for keeping it in a stationary position.

Also to the lower left is a pull rod which is used to adjust the governor setting. There are also two rotating knobs which operate the choke (on the left) and the throttle (on the right) respectively.

Centrally mounted on the back of the gearbox is the gear lever, with five positions. The central position is reverse gear, with a neutral position both above and below reverse. Both top and bottom positions are forward gears — one is the normal travelling gear, whilst the slower gear is used when rolling tar. Do not change from one gear to another whilst the roller is in motion, as this will damage the gear teeth. Always bring the roller to a stop by disengaging the clutch and applying the brake before selecting another drive gear, then re-engaging the clutch.

Use of the steering wheel is fairly obvious, as it drives a worm gear that pulls on the steering chains going to the front roller. Just below the steering wheel is a lever used to operate the power driven steering mechanism which takes power off cones fitted to the drive shaft. This isn’t much use whilst the roller is in motion, as it is too slow-acting and use of the manual steering wheel is relatively easy in this case. However, it is very effective in moving the turning the front roller when stationary as the steering is quite heavy — hold the lever to the left to turn left, and to the right to turn right. Note that this mechanism only works when the clutch is engaged, although it works no matter what position the gear lever is in. The roller does not have any compensating suspension, so care should be taken to keep it on as much a level surface as possible, as the track is quite narrow. If one side is allowed to drop into a dip in the road, the roller can assume quite an alarming tilt from the vertical, and we have no wish to find out what its limits are.

Also note that that the drive roller is smooth steel, so traction is very poor on slippery surfaces, particularly grassed areas, and it is easy to get the roller trapped in a slight dip in the ground in these circumstances. Take extreme care when crossing rail tracks as it can slip alarmingly on steel rails in any direction.

Stopping the Roller

There are several ways to stop the roller’s engine.

  1. Allow the engine to use all the fuel. This is quite effective, but may result in you having to wait for a while. Care should be taken when the fuel is finally running out, as the fuel mixture becomes leaner in the piston and more explosive detonation occurs. In order to keep the engine from rotating at excessive rpm due to the increased power of detonation, adjust the governor setting to reduce the number of firing strokes.
  2. The preferred method is to turn off the fuel taps and allow the engine to stop from fuel starvation, as for method 1. The same cautions apply. However, this doesn’t always work as sufficient fuel may leak past the taps to ensure continued ignition.
  3. This method should only be used if method 2 fails. Retard the spark and open the decompression valve, which will reduce the power generated in the piston so that it will be unable to maintain a firing cycle, and the engine will stop fairly rapidly.
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Last updated 3 January 2005.
Content copyright © Russell Jones 2001-5. Reproduced with permission.