Problems resolved & modifications

New oiler were made in steel and in place of the M4 thread M5 was used and the bearing drilled out so that the oiler thread would pass well into the bearing and just 0.5mm short of the main crank shaft.

2. This also means that the big eng shell could also rotate and so a pin will be installed in the outer part and stop the shell rotation.

3. The exhaust tends to rotate in the cylinder head when the engine is running so a nut with be made to lock again the cylinder head and stop the rotation.

4. The main oiler delivers the oil much too quickly so my design is at at fault and a new design will be worked out.

5. The lever as made originally was not done to the plans so an alternative one has been made and this will be tested when the engine is next run

6. The key ways do not lock the flywheel tightly to the shafts so the flywheel will be drilled and tapped M6 to take a allen grub screws to lock down onto the keyways and stop rotation.

Item 1. This was in fact completed several days ago and the new oilers look the part - in my opinion.

Item 3. The locking nuts has been made and the thread on the caste iron fitting extended by three turns. the exhaust has been refitted.

Item 4. The mail oiler was taken apart and the centre section was found that it could be reversed. Thus a 1mm hole was drill in the centre section in place of the 3mm hole and it is hoped this will resolve the excess of oil entering the cylinder.

Item 6. The flywheel have been drilled and tapped and locking grub screws are now in place.

Following a suggestion on the Engineering Forum "You may have to think about balancing the flywheels on your engine to cut down the vibration, you can do this by removing some weight from the flywheel and diametrically opposite the crank pin, this can be a trial and error job."

I decided to balance the actual flywheels following further discussion with other friends who have engineering experience.

A simple support was made from ply and then two piece of Stainless steel were bolted to it set level on the bench and then the wheels turned. When they stopped the outside was marked in pencil and holes drill opposite.

From the run to day it was found that the balancing of the flywheels has helped a great deal to cut down the vibration ..

Next task to balance the crank shaft webs. Additional weight to the non big end side will be a great help !!!

Also the oil caps to the main bearings and to the big end need a small hole in them to allow oil to drain out else there is a vacuum created and no oil drains through.

Today I was able to make up the parts to go onto the crank webs to try to balance the crank shaft a little bit. Anything will be better than nothing.

The two balance weights were cut from 63mm round bar and then machined to 10.5mm thick and the end taken off to allow for clearance. This was then cut in half and the surface where it had been cut milled to an accurate datum and at right angles to the face. The parts when then drill to act as pilot holes into the webs.

First the webs were milled to ensure similarity and then drilled and tapped for M5 x 0.8 and the weights drilled out 5mm as tight clearance for the M5 studding.

The crank is still out of balance but much better.

Larger balance weights could be used so I may make bigger ones cut from 76mm bar but let's see how these go.

I appreciate that this does not take account of the moving masses and that will be considered in due course.

I have been told by a friend's at the Bredgar and Wormshill Light Railway that it is a fact is that it is IMPOSSIBLE to balance a single-cylinder engine. The best that can be done is a compromise.

This is the suggestion :-

1. Locate a set of digital scales.
2. Take apart the crank assembly, then with the top half (little end) in your hand level with the scales weigh the bottom half of the rod call this BCR.
3. Now take the big end in your hand and weigh the top half of the rod call this TCR.
4. Now weigh the piston and all that goes with it call this P.
5. Add the weight of the top half of the rod to the weight of piston which is TCR + P.
6. Now you need to assess 65% of this weight which is 65(TCR + P)/100.
7. Add this weight to BCR and machine a piece of material to this weight to fit over the crankpin thus {65(TCR + P)/100}+BCR
8. Now you need to make weights that balance the crank shaft.

That is the best one can achieve.

I am guessing that if you weighed the big end of the crank with the mass attached it would give one a starting point as to the mass required.

I know I am re-inventing the wheel but this is what the chaps must have done years and years ago (1910 ??)

In this article (click for the link) in place of machining up a piece to fit over the crank pin it gives the idea that a scale pan holding the necessary weight can be used

I have now substituted the drain bung with a right angle 1/4" BSP male - female elbow and a bung in the end to make emptying the water from the evaporation tank easier.