The finished engine

Above: The finished engine

Making a Billabong engine

My story started back in 2007 whilst taking some scrap parts of a Chrysler Galant motorcar to the scrap yard, I discovered that the distributor gears, which on the Galant drove off the crankshaft, with a ratio of 2 to 1 would make ideal skew-gears for a small side-shaft engine I had been contemplating building.

I have found that over the years old engines have become hard to get and so expensive, so I thought I would make an engine using bits of scrap. I originally looked at an old piston vacuum pump with the idea of using the base and crankshaft for my engine, but I did not like the idea of wrecking a working vacuum pump, so it was back to the drawing board. Some years ago, while restoring my Islington engine, I had made a small furnace and cast the parts needed for the fuel inlet hot tube system, so I thought “to hell with it, if I can cast a couple of parts, why not cast all the parts required to make an engine!?”

I spent some time drawing plans; it was not easy but I worked out the size of the various parts by measuring my 8hp Ronaldson–Tippet, and made the model approximately 1/4 inch to 1 inch of the Ronnie.

Making patterns

The next job was to make the patterns, making most of them from wood, a job that took about three weeks. When I showed the wooden flywheel to someone, they remarked “How did you make it?” I said I took a piece of wood and carved away anything that did not look like a flywheel. I wish it was really as simple as that!

I made several mould boxes, and found some clean Mallee sand. At this point I decided that it was time to learn some more about foundry work, so I travelled to Castlemaine to visit Billman's Foundry. This was actually the first time I had seen inside a foundry. The owner kindly showed me around and gave me lots of advice. He also checked my patterns, and said they would be OK.

The next weekend I arranged some help from friends. (Larry and Sue Conner, along with local guy wayne Rutherford and my son Allan). We had some trouble with the crankcase mould, but after three goes, the pattern came out OK.

The furnace was lit, and when burning well, we put in the iron and turned on the blast from an old vacuum cleaner. After a while, molten metal showed at the taphole. We then waited the recommended eight minutes before removing the plug, expecting to see molten iron, but we got nothing. This was a bit disappointing, but we decided to try again the next day. We started again, this time using more coke and less iron. This time after removing the plug, out came a flow of orange coloured molten iron, which was poured this into one mould, and we started on the second. But the iron started to cool and left us with a half filled mould and iron set solid in the crucible. Another failure!

There are always lessons to be learned from failures, but I still hadn't leaned to get Billman's Foundry to do my casting.

Assorted patterns ready for use

Above: Assorted patterns ready for use

Filling the mould

Above: Filling the mould

Three boxes ready for pouring.

Above: Three boxes ready for pouring.

The first Pour

Above: The first Pour

New furnace

I decided to try again with a new furnace, this time constructed from old hot water cylinders, with a liner of crushed fire bricks and fire clay. It took three days crushing up a load of fire bricks to make enough material for the liner. The finished furnace was a cupola type with a drop bottom, a 10inch cylinder, four-feet high with blast supplied from a garden leaf blower.

The big day came to test it. I rammed up the boxes with the patterns. Then, when the coke was burning I added 18 kg of iron, followed by four inches of coke, then a further 18 kg of iron and turned on the blast. In approximately ten minutes I had a good supply of molten iron. The moulds were filled but I forgot to put weights on the boxes. The box with the flywheels lifted and I lost the flywheels, but most of the other parts turned out well.

The next day I started to machine the parts, starting with the cylinder head. When it came to drilling the head stud holes, I found that the core for the water jacket had been too big and the stud holes came on the edge of the water jacket. I thought Oh-well, another lesson learnt.

Visit to the hospital

To machine the outer cylinder I mounted the casting in the 3-jaw chuck on my old Macson lathe. The fact that it had a flange on one end, I thought it should be OK without a centre. I first machined the flange, then put this end in the chuck and machined the other end, and then started a light cut down the side. About one inch from the end I noticed the tool starting the cut in deeper - I just went to switch the lathe off when disaster struck. The tool bit in and pulled the cylinder from the chuck and the cylinder smashed my left hand against the lathe. I said something like “golly-gosh”, then looked at my hand, it was a mess.

The sharp end of the cylinder cut through the back of my hand and I could not see the two small fingers. I thought “I am gunna get in trouble when my wife sees this!” I wrapped a towel around it, and picking up the cylinder to have a quick look; it still seemed OK. I then fronted the Wife.

As we did not have a car at home that day, my wife Maree, rang for an ambulance and I was taken to the Robinvale hospital, where they found that the fingers were still there, hanging underneath. They then sent me to the Mildura Base Hospital where they X-rayed the hand and found the bones and tendons had been cut. I was then put in an air ambulance and sent to St Vincent's Hospital in Melbourne. I then spent two days there getting wires and screws put into my hand. That was followed by approximately 4 months of trips to Melbourne and Bendigo hospitals for treatment.

When I got around to inspecting the lathe I found the two bolts that hold the screw nut to the cross slide had come loose, thus allowing the cross slide to move on its own and cause the tool to bite in. Another lesson: Maintain your equipment.

The results of a failed pour

Above: The results of a failed pour

A later pour produced useable casting.

Above: A later pour produced useable casting.

Back to the engine

Returning to the engine, I very carefully machined the remaining part. First I machined the outer cylinder, then the cylinder liner. The crankcase needed a jig made to hold it to the face plate on the lathe; this I made from some heavy ten inch channel. I had to get main bearings caps milled by an outside company as I didn't have a milling machine. I also had had them line-bored by the same people. I made bronze main bearings. The crankshaft was made using two 3inch by 3/4 inch plates together. Then I bored the shaft holes 1 1/2 inches apart on my lathe and then cut the shape of the counter weights with the angle grinder. Then I made a jig to machine them on the lathe.

The shafts and crank pin were machined for a press fit. A jig was made to assemble the crankshaft which was pressed together with Loctite. When I came to machine the piston, I found that it had a blow hole in the top, a problem I also had with the cylinder head. So it was back to the furnace to recast these parts, as well as the two flywheels, again. The pour failed, so I tried again. This time I got a piston but the cylinder head and flywheels were not suitable. Fed-up at this I decided to get Bi11man's Foundry to pour the head and flywheels. I delivered the patterns and was told that the parts would be ready in about three weeks.

While I was waiting for the castings I got on with machining the piston, made some rings and a gudgeon pin. The big end was cut out of a piece of 2 inch bronze shaft using a small angle grinder, and finished with a file. The con-rod was tackled next. I made an adjustable rod to work out the length, then machined the rod from a piece of 1 3/4 inch shaft and put it all together; it turned over OK so I knew everything lined up.

Making the carburettor

The next job was the carburettor and fuel pump. Having made the patterns and found some finer sand, rammed up the moulds and was ready to cast some brass. I used my old small furnace with a crucible this time. With the help of a friend (Jim Tolley) we loaded up the crucible with scrap brass and turned on the blast. I had read somewhere that putting crushed glass in with the brass helped to form a skin on the top to keep out oxygen. Soon the brass was melted and as I lifted the crucible out with tongs to put it in a pouring ring I then knocked it over and lost most of the brass. The next day Iim came around again and we tried it again, this time it went perfectly. Now it was just a small matter of machining away all the bits that did not look like a carburettor and fuel pump. I had decided that the engine should be a throttle governed type, so I used a throttle butterfly from an old brush cutter carburettor inside the casting. The fuel pump was a piston-pump type, working off the side shaft.

The valves and valve housings were made by cutting down Briggs & Stratton valves. The housings were machined in the 4-jaw chuck and the valves lapped in.

It was then on to the governor. The balls and arms were machined from 5/8 inch shafting. The governor was mounted on the side of the cylinder with a belt drive from the crankshaft. When it came to making the oiler, I visited all the second-hand shops in Robinvale and Swan Hill, until I found a small wine glass of the correct size and shape; this was taken to a glazier who cut the glass and drilled a hole in the bottom. The glass cost me 50 cents to buy, but having the hole cut cost $30! The rest of the oiler was made from scraps of brass.

The bearings for the side shaft were made of steel, with bronze bushes. I had chosen to have a low-tension ignition system which meant making an ignitor. The body, made from pieces of cast iron etc was all straightforward. However, making the small mica washers was a pain. In the end I punched a series of holes in the sheet of mica and then cut the sheet into squares using the angle grinder. These squares were then put onto a bolt and turned down on the lathe. The end result was a stack of small mica washers.

Assorted brass castings

Above: Assorted brass castings

My damaged hand - Be careful

Above: My damaged hand - Be careful

Machining the piston

Above: Machining the piston

Machining the cylinder head

I had now reached the point where I needed the cylinder head and flywheels so my wife and I hooked up the caravan and headed off. We picked up the parts and on to visit friends (Larry and Sue) for a few days. I spent some time in Larry's workshop cleaning up the castings.

The cylinder head, which we had made solid, required boring out of the combustion chamber and water jacket. The head was then fitted to the cylinder and the ignitor assembly fitted. I then moved on to fitting the valve housings, the carburettor and the linkage from the governor to the carburettor.

To fit the sideshaft I made a jig to hold the shaft in place with the skew gears meshing, and then drilled and tapped the mounting holes. I then bolted plates to the engine and tacked the side shaft hearings to the plates. When I was sure that the shaft turned freely, it was case of welding the plates to the bearings.

After I had machined the flywheels I took them to an engineering firm to have the keyways cut. I also had the keyways cut in the side shaft by the same company. Gib- head keys were made and fitted.

The valve rockers and lever to operate the fuel pump were made and the ignitor finished, which involved making a tripwheel for the sideshaft to operate the ignitor. To test the ignitor I connected it to a battery and turned the wheel by hand - the ignitor worked perfectly.

All that was left was to cut the keyways in the cams at the correct valve timing, then assemble and test the engine. I cut the keyways in the cams on the lathe, but when I checked the valve timing I found that I had cut the keyway in the exhaust cam in the wrong place and so I had to do it again. More learning!

First start-up

Once the engine was assembled I tried to start it, but found it did not have enough compression; there was leaking around the valve assemblies. I also suspected that I had too large a combustion chamber. This had me worried for some time but the first thing was to fix the leaks by regrinding the valves and fitting stronger valve springs. I then made a new piston, with a longer Piston top. to take up some of the combustion chamber.

On the 24th of June 2008 it was finally time to test the engine. I hooked up an electric drill to the flywheel (with a belt) and filled the carburettor bowl with fuel. The engine started instantly and ran very well, with no vibration. Happy that all was well, I connect up temporary fuel and water systems and after making a few adjustments, restarted the engine and ran it for 10 minutes.

All I had left to do was to make fuel and cooling tanks, a trolley and all would be done. The question was what was I going to call the engine? After some thought the name BILLABONG was chosen and a brass plate with the words Billabong Engine, Made by L W Hopcroft, Australia was made and duly fitted to the engine.

More problems

One day while in the workshop I held the inlet valve down by hand and turned the engine over; this was a mistake as the long piston top hit the inlet valve and bent it. Upon removing the valve housing I found two cracks. Although the engine still ran I was not happy, so I made new patterns for modified valve housings, and I modified the cylinder head pattern to have a smaller combustion area. Another modification included a mounting for the exhaust rocker shaft. This meant I would be able to use my original flat top piston.

After the new cylinder head and modified valve housings were fitted I ran the engine to see that all was OK. It was then time to dismantle the engine and paint it with enamel. This done the engine was re-assembled in time to be exhibited at the Australian National Rally at Murray Bridge where it ran for three days, and drew a lot of interest. I've since built four more complete engines and sold several sets of unfinished castings to people who want to build their own Billabong engines.

Machining the flywheel

Above: Machining the flywheel

Parts of the flyable type governorAbove: Parts of the flyable type governor

I have now built four Billabong engines

Above: I have now built four Billabong engines

Brass name plate

Above: Brass name plate