Bullarto Vintage Tractor Pull, March 2015 - page 2 of 2

2016-01-25 Robin Whittle rw@firstpr.com.au  (Added a linke to a YouTube video on 2016-07-11.)

The Tractor Pull will no-doubt be on again on a Saturday in March 2017:


This is one of several pages concerning Daylesford and places nearby.  The index for those pages is here: ../.  

This page concentrates on Lanz Bulldog tractors.  The first page is:  ../06-bullarto-tractor-pull-march-2015

I really enjoyed the 13 March 2016 tractor pull too.  I don't have any photos, and the blue-gray Lanz Bulldog tractor pictured below was not there.  However, there was a similarly handsome Lanz Bulldog model - a 1950 model P 50HP - and I have a video of it driving a dynamometer.  The sound and the flames coming out of the exhaust are a special treat:

https://youtu.be/zqCvim1GuXg    <<<--- YouTube video!

I had never previously wondered to myself "How much would a tractor like this cost?  Where would we keep it?? . . . . Where would we get a full semi-trailer low-loader float to move it around???"

But this is what happened when I encountered these magnificent Lanz Bulldog tractors. 

These are single-cylinder tractors, which run on oil of almost any kind, and apparently will run on tar if it is heated up enough.

The piston runs horizontally and the cylinder head protrudes from the front.

It is not a diesel.  The compression ratio is modest.

There is no spark plug, or even a glow plug.

Instead, there is a bulb of metal as part of the cylinder head, which must first be heated with a blowtorch (or in recent decades, a gas torch) and which sets off the explosive combustion of the fuel air mixture, and remains hot enough from this to do it again in the next cycle.

Once the bulb is warmed enough, the engine is hand-cranked from the side (note the enormous flywheel) with the valve gear open, so enough speed can be gathered.  The the valve gear is engaged, and fuel goes into the compression stroke for the first time . . . and with luck, it fires and keeps going.

The high air inlet is a feature of these types of tractor.  Perhaps it is to reduce the ingress of dust.

Here is a similar tractor, but this one uses a diesel, not a hot-bulb engine.  I think it is a single-cylinder and it is clearly a kindred spirit of the Lanz Bulldog.

This one is roadworthy and registered.

The Lanz Bulldog tractor was designed and made in Germany.  There's a lot of information on these and their two stroke hot bulb engines on the Net:



An explanation of hot bulb engines is here:


They blow smoke rings 10 metres or more into the air.  I was unable to capture this in a photo.

The sound of their engines is very distinctive.  Around 6AM one Sunday morning in late 2015, I heard the sound as I lay half-asleep.  Someone was driving a Lanz Bulldog or similar tractor through Daylesford:  Poot-Poot

I guess this means it has a 35 horsepower engine.  There's a list of models:


which makes me think that this was made in the years 1936 to 1955.  This page, one of many, makes me think this tractor is a D8506 or similar:


Here is a 1952 D8506, with electric starter:


These 35 HP models have a 10.338 litre displacement.  This is a big engine to hand crank, and with this model, the steering wheel detaches to be used as the crank handle.

There's a video of a similar model being started here:


This video is by Bob Twyford, who has - or at least had - a tractor museum in Red Cliffs, near Mildura, in northwest Victoria.  I couldn't find a website for the museum, but it would no doubt be associated with the Tractor Restoration & Appreciation Club of Sunraysia:


Further research indicates the museum is, or was, located at the corner of Azolia St and Cocklin Avenue.  However, the lack of Internet presence now makes me wonder whether it is still operational.  The last of the videos on Bob Twyford's YouTube channel is from 2013.

I didn't see one started, but the owner of this tractor showed me around it and told me more fascinating details about it than I can remember now when writing this web page.

He showed me how he could close off the fuel and open the valve gear, let the engine slow down - it took a while due to the huge flywheel - and then as it almost came to a stop, hit a compression stroke so the engine bounced backwards in the reverse direction.  Then he opened the fuel supply and activated the valve gear and the engine sprang to life again, running backwards.

This is not such a good idea, since the oil pump doesn't work.  So he repeated the process, letting the engine slow until it rocked up against a compression stroke which bounced it forwards, and soon had the engine running forwards again.  I don't know if there is any practical purpose to this, but it is quite a arty trick which demonstrates the simplicity of the machine.

Simplicity and robustness was one of its major selling points. 

The unpainted casting is the outer part of the hot bulb.  This is what must be heated with a blowtorch.

On the left the little handle by the flywheel controls the valve gear and fuel.  I recall this one was running from sump oil.

The side panels are for radiators.  I recall that there is a water jacket with convection circulation, rather than relying on a pump.  The screw-on panels enable control of cooling so the engine temperature doesn't fall to far in cold conditions.

I understand that the steering wheel with its shaft plugs into a hole in the centre of the right flywheel cover.

Here is a little video of the tractor in action.

This one has a starter motor, and I can't see where the hot bulb is.  Perhaps it is a diesel. 

Here is a diagram from the manual from a similar model:


If the above file is no longer available, please let me know and I will place it here on this site.

This does seem to be a two-stroke diesel, since on page 37 the manual describes an injector.

All the axes of rotation are left-right, whereas in most tractors the crankshaft is front-back, with the gearbox having this axis and a pinion gear driving the crown gear on the pinion to create the left-right axis drive for the axle. 

This means that a power take-off shaft (front-back axis) would be quite tricky to add.

The fan is evidently between the left and right radiators.

Bob Twyford's four videos on restoring a 35 HP Lanz Bulldog tractor show some of the insides, including a view of the piston from the left-facing exhaust port.

This page concentrates on Lanz Bulldog tractors.  The first page is:  ../06-bullarto-tractor-pull-march-2015

This is one of several pages concerning Daylesford and places nearby.  The index for those pages is here: ../.