Preservation

The updates start about two months into the project. Although little work in dismantle took place in the first month. During the first month, we concentrated on preservation of the rusting engine. Kevin had already filled the cooling system with diesel before delivering ‘Devon’.

This should prevent further internal decay. The outside was and still is being sprayed daily with penetrating oil, to help prevent and help loosen nuts and bolts etc. and prevent further external decay.

Cylinder 1, has the most rust building up around the head and upper cylinder. It was important that this area was sprayed with oil regularly. On a damp day, you can see the moisture collecting on the surface. This is mainly because of the engine once fitted in a sea going vessel. This environment has allowed salt to embed into the metal. When the atmosphere becomes moist the salt draws the moisture into the metal. If the cylinder is to badly decayed then a new one may have to be purchased. The decay could have thinned the wall sufficiently enough, that it may split when the engine is running.

We removed the eight doors as soon as we got a clear date to work on the engine. It is quite clear from this photo that the crankshaft has not turned for sometime. We also found a lot of sand in the sump along with fishing line. The crank joined the list of parts that are in need of regular oil spraying.

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Water Pump

The water pump was quite a task to remove. Mainly because the way in which the crank had seized. It made access inside the crank case very tight. Once off the engine the pump disassembled with ease.

With the pump housing being manufactured in brass rust is not a problem. The photo’s illustrate how a quick clean with a soft wire brush, to remove excess grime and a short time in the sand blaster can bring the pieces back to life.

The pump can be divided up into main areas or restoration :

1. Valves:
   
   
   These had been replaced at some point. Looking at the shape of the rubber disc within the valve assembly, these were made from a piece of rubber matting or something similar. Despite the quick-fix solution, they have appeared to have stood up to the task quite well.

2. Valve Springs:
   
   
   These are very corroded, so will need to be replaced with new ones.
   
   
3. Main water pump casing
   
   
   With a little cleaning it is possible to get the brass shining again. The valve seats on the outer two holes are still in reasonable condition.
   
   
4. Gland Nut:
   
   
   The knurled ring is badly burred, so will need some attention Possibly a new one will have to be made..
   
   
5. Piston:
   
   
   This has got a little wear in the sides, so will have to be replaced or machined. If Machined then a sleeve will have to be made to compensate for the difference in size. The rod joint will also need re-packing.
   
   
6. Air Chamber:
   
   
   Out of all of the parts on the water pump, this is one of the most viable, so it will need a good clean. The air bleed tap will also need to be dismantled, cleaned and reassembled.
   
   
7. Gland Packing:
   
   
   This was the two pieces that came out of the pump. They will have to be replaced on a regular basis to prevent leakage and damage to the piston.
   
   

Diagram of Water Pump Available

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Removing the Heads

Some History Revealed

Removing all four rocker covers proved to be quite a job, as the nuts had seized onto the studs. Plenty of heat worked eventually. Once off, work could start on stripping the rocker and push rod assemblies down. These have to be removed to access the cylinder head studs and nuts.

Whilst the rockers appeared quite rusty they are restorable. However the steel rocker end plates crumbled when touched. Eight more are being made, along with all new studs.

With the rocker removed from cylinder four, something did not appear quite right. Closer inspection revealed the valve spring was fully decompressed. At first it was thought that the collars had popped out. However when the spring was removed, it became apparent that the valve stem had broken, possibly during operation.

Heads

With the rocker assemblies removed it was now possible to take the heads off. Our expectation was that the head bolts would be very tight. This did not prove to be the case and with the use of a torque wrench, they cracked and released quite easily.

Lifting the first head off cylinder four revealed further clues to what had happened to the J4 at the end of its previous working life. The cylinders were full of sand, which suggests that it was possibly submerged in the water at some point.

At a first glance, the valves appear to be in good order.

The sand was quite compact within the cylinder. We removed around 1 1/2lbs in weight using a teaspoon. The bottom inch was a mixture of sand, calcified salt and mineral. Which had to be gently chipped away with a chisel. It was not possible to remove all the debris, whilst the piston remains in the cylinder.

With the majority of the debris removed the crown of the piston could be seen, it does not appear to be in very good condition. It looks like the surface of the moon. The liner also has severe pitting.

All of the other cylinders were full of sand, with the exception to number one. This was actually full of oil and once removed the crown on this piston was quite smooth.

Head number three will require new valves and guides. Four new pistons and liners maybe on the Christmas list.

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Gear Box

Removing the gear box on most modern day engines is a relatively simple task and is something that can be removed as a complete item. Here is an example on how some things don’t go with the norm.

Four bolts around the gear box housing go into the crankcase. Once these were removed we were under the impression that the box would slide off. After half an hour of wiggling, pulling levering with a big bar we realised that this was not going to be a straight forward job.

A coffee break and consultation with diagrams still shed no further light onto the situation. Of course looking at the diagrams now it is quite apparent that the gear box has to be split in order to remove it from the engine. I phoned a man in the know for some advice and he went through a detailed step by step procedure on how to split and remove the box.

The first task is to remove the starting handle from the top of the box. This allows the single chain to drop down into the box. Once this has been done, the top casing can be unbolted and removed. This allows access to the upper shaft. The double chain that connects between this shaft and the lower is what prevents the box from being removed whilst complete.

We were not fortunate enough to find the joining link o split the chain. So we had to split the chain with the careful use of a small chisel. Both chains are totally rusted and beyond repair, so two new ones will have to be sought.

Flywheel

Kelvin Fitted two different size flywheel to the engines, depending on whether they were intended to start by hand or with an electric starter. The larger size 28 inch diameter being fitted to the hand start specification. ‘Devon’ is fitted with the 22.25 inch diameter. Whilst this is intended for electric staring, although I have been informed by Kevin that it is possible to start the engine by hand, it will take a little more muscle power to get the momentum going.

We thought about and put off the removal of this hunk of metal for a number of weeks, mainly because of the modification that had been done to the centre of the wheel. This is a non-standard part and fitted to possibly drive a pulley. The problem this presented us with, is that the hub is restricting access to the bolts holding the flywheel on to the crankshaft flange. A number of attempts were made to undo the bolts with spanners but with no success.

The final option left open to us was to cut the bolt heads off. This was achieved by drilling a pilot hole into the centre of the head, to the depth of the head. Then drilling the hole out so it is just under the size of the thread diameter. Drilling the hole too big would damage the flywheel. Once the holes were drilled the bolt heads could be chiselled off.

We then got hold of a puller that fitted around the non-genuine centre hub. With a tense atmosphere we slowly wound the thread on the puller. Much to our surprise and disappointment the centre hub slowly came away, leaving the flywheel securely fastened.

Left scratching our heads and a well deserved tea break plan B was devised. The wheel has three holes tapped in it to use 3x whitworth bolts to force the wheel off. Closer investigation discovered that the large amount of rust around the flange may have a firm bond and to use the forcing bolts may damage threads.

We tried a heavy bar for leverage but this ended up bending. So brute force and ignorance took over. The use of plenty of heat, the bent bar, a block of wood and a big hammer. After an hour and a half it finally give up the battle and it came off. One word of caution for this approach, go careful not to hit it too hard near the edge of the flange, especially if your toes are in the area. This flywheel weighs a few lbs. Victory was ours although we were very hot and bothered towards the end.

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Oil Pump and Gallery

The pump was quite a challenge to remove, partly because of working blind to disconnect the pipe to the gallery and the connect rod. Removing the gallery was also quite difficult because of the rust that had built up around the individual delivery pipes. After struggling to try and manipulate the gallery past the seized crank, we were left with only one option to cut it in two and reassemble.

The pump has a filter fitted to the bottom of it. Basically this is constructed from two brass discs fixed about 3/4” apart. A fine metal mesh is soldered between the discs to form a cylinder. As you can see in this picture, the old mesh has been removed and awaiting a new piece to be fixed in place.

The only other two items that will need replacing are the spring which ensures the outlet ball valve closes and a new piston.

Timing Chest

In order to remove the camshaft, crankshaft, water and injection pump drive, the timing chest needs to be dismantled and all of the gearing removed. The chest contains four separate gears with a fifth incorporated in the crankshaft casting.

Timing the engine correctly is vital to prevent damage on the first turnover. However it takes at least thirty revolutions before the timing marks line up once first set.

With the flywheel off, the outer timing chest cover can be removed. In Devon’s case to reveal a rusty mess.

The far right gear that normally drives the magneto had been adapted on Devon to drive a generator. The brass pipe in the middle of this photo is the oil feed pipe to the gears. Obviously it has not been delivering oil for a number of years.

The camshaft and water/injection pump gears are fastened by means of a nut and copper locking tab. Once these are removed two 1/2 whitworth bolts are screwed into the gears which push the gears off the shafts. The internal threads had been slightly damaged so it was not possible to use this method. So they were gently eased off with a couple of large screw drivers.

It was not possible to see the original timing marks of the gears. Putting new timing marks also seemed inappropriate, as they may come off during the cleaning process. However the rust has not appeared to cause major damage to the teeth.

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Cylinders

Unlike modern engines where the crankcase and cylinders are all in one block, many of the vintage engines have the cylinders bolted onto the crankcase. This is the method used by ‘Kelvin’ in the manufacture of many of their earlier engines. ‘Devon’ has four cylinders, all of which are individual.

One of the first jobs is to undo the bolts at the lower con-rod end. This contains a split pin which has to be removed first before undoing the bolts. . Once both bolts have been taken out the bottom section of the crankshaft/con-rod bearing can be removed. This will allow the cylinder to be lifted up with the piston and con-rod inside.

The cylinder is attached to the crankcase via six studs. Accessing the nuts can be quite difficult especially if the crank will not turn and if the piston and con-rods cannot be removed. In our case both problems occurred.

Each stud has two nuts, the first drawing the cylinder tight and the second locking against the first to prevent it from undoing. By lying the engine on it’s side (which is no easy task manually) access can be improved. However a number of universal joints and extensions had to be used, with heat on some to break the corrosive seal.

In many cases it was possible to get the socket onto both nuts together which allowed the stud to be drawn out of the cylinder.

With all nuts removed and by luck the majority of studs the cylinder needed shocking to break the seal between it’s base and the crankcase. A few swift blows from a number of directions with a rubber mallet did the job.

Lifting the cylinders off is no mean task, they take a lot of wriggling a pulling at the same time, a job that would be made even more difficult if more studs were left in place. We had added weight of the con-rod and piston to lift as well.

The procedure was repeated four times, until all cylinders were removed. After carrying out this job in one afternoon, you will know what hard work is....

Additional pictures of the cylinders ,

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Crankshaft

This was going to be the last thing to be removed, but due to there being problems with removing the camshaft, we were forced to remove the crankshaft first. With this removed it would open up both ends of the crankcase, allowing the camshaft to come out with the bearings still attached.

The crankshaft is held into place by six white metal bearings, which are encased around large housings which split in two. Each housing is fixed to the under side of the top of the crankcase by two large y-bolts. There are twelve y-bolts, two for each bearing. It took close on three hours for two of us to undo all twelve bolts and plenty BFI (bruit force and ignorance).

The usual procedure is to turn the crankcase upside down. The locking screws should be undone and the locking plate removed. This then allows the cap bolts to be removed . The bottom cap and bearing can then be removed. The procedure is repeated for remaining five bearings.

The crank can then be lifted up and a piece of plywood can be slid in between the crankshaft and the remaining half of the bearing. This allows the crankshaft to be slid out easier, rather than struggling to lift the webs of the shaft over the top half of the bearing housings.

Due to the poor condition of the bolts holding the bearing assembly together, the only option was to remove the crankshaft with the main bearings and casing attached. This is possible to do because of the way the crankcase is designed.

With all twelve y-bolts removed, it was possible to lift the crankshaft out. Not quite as simple as it sounds!. I will discuss the finer detailing when it is reassembled. The crank is very heavy and should only be lifted with good lifting gear or two people.

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Camshaft

Kelvin were very economical in the design of the camshaft. They were constructed in module sections. This consisted of a front and rear end with modules welded in between . Each module contains a bearing, inlet and exhaust cam. In a J2 (2 cylinder) the shaft would have two modules welded in place, a J3 would have three welded in and J4 four welded in.

The cam is held in the crankcase by six bearings. Four of which are made from bronze and are fitted inside the crankcase. There is a ball race bearing at the front end and a simple bronze bush at the far end. The four inside the crankcase are of a ring nature These are supported from the under side of the top of the crankcase. Each one is situated between each inlet and exhaust tappet bushes.

Like the Crankshaft, the camshaft is one of the main parts of the engine that cannot be easily replaced. A new one could be machined, but the cost would be astronomical, Therefore it is vital that this component is handled with care.

Unfortunately, when the engine was last rebuilt a few small vital parts had not been put back. The tappets which operate the push rods are meant to have woodruff keys fitted. This stops the tappet from turning around inside the brass bushes. With these missing the tappet can turn and cause excessive wear to the camshaft lobe. There are only two cam lobes that have the original profiles, the other worn to obscure shapes.