Three cylinder 150cc

[George Punter]

View attachment 108002 Y This engine has been designed as a power unit for a 5" gauge scale model diesel loco. The engine is 3 cylinder 150cc cross flow side valve water cooled fourstroke petrol engine and has both petrol and oil pumps. It is linked to a two forward and one reverse gearbox via a centrifugal clutch with all wheels on the loco being driven. All design work,patterns and aluminium casting were made in my workshop. The crankshaft is of the 4 bearing type and was machined from a solid billet of 4140.

 

[Jones]

That looks absolutely sensational! How does it sound?

 

[George Punter]

I still have some minor work to the ignition system ( the red bits on the back of the engine). This includes the disc that times the Hall effect transistor and fitting out the contact points in the distributor. I had hoped to have had all that completed soon but I am busy preparing for a trip to the Docaster model engineering exhibition ( bring over the Saunderson & Mills 1/4 scale tractor! )If this engine sounds like the other three cylinder engine I have made it should be OK. Photo shows gearbox internals.

 

[Charles Lamont]

Oh, very nice. Is that a T-head, with 2 camshafts?

 

[George Punter]

Yes there are two camshafts and both ends of both shafts are used to drive the oil,petrol pump,distributer and ignition. Both shafts are gear driven.

 

[kuhncw]

George,

You've done a very nice job on the three cylinder. It would be interesting to see photos of more of the parts.

Chuck

 

[George Punter]

Good Day Chuck,
I will include some of the photographs of this engine under construction including making the castings. The first set relate to the gearbox, it's internals, patterns and castings. There is also a photo of the underside of the engine showing the bearings. More photographs to follow when I have sorted them out.

Georg

 

[George Punter]

D D Photo 1 shows the sand core ( using a chemical to set the sand). These are the shapes that create the empty spaces inside the engine and have been made in take apart wooden boxes. Photo 2 shows patterns and core boxes. Photo 3 show line boring the crankcase. Photo 4 machining one set of ports in the engine casting - also show bronze valve seat and guide.

 

[George Punter]

Photo 4 . Photo 5 polishing crankshaft bearings.

 

[mertkan37]

tebrık ederım . bu motorun planını nasıl bulabılırım?

 

[Lloyd-ss]

I look at some of these projects with my mouth hanging open in awe. So humbling......but inspiring!
Lloyd

 

[George Punter]

Lloyd in the early 1960s I went to the Model Engineering Exhibition at the Symore Hall in London. This was my first visit to such a show and I was inspired with what I saw. Now ,many years later, I hope that some of my models have a similar effect on people new to our hobby. We all model at out own level, depending many factors ,but the main factor is the enjoyment we receive in being creative.
George.

 

[Lloyd-ss]

George, The actual mechanical part of machining might be considered a left brained activity, but as you said, the creative right brained part of it is such a huge driving factor. We have those moments of personal inspiration too, where you step back and chuckle, and think, what I just did was pretty cool.... but with some humility too, LOL.
It is wonderful that you experienced that inspiration at Symore Hall. Moments to be remembered and even cherished, for the effect that had on your life.
Lloyd

 

[kuhncw]

George,

Thanks for the additional photos. Very nice work and an interesting design.

What is the bore and stroke?

Chuck

 

[George Punter]

Chuck the bore is 40 mm and the stroke about the same. Three years ago while on holiday in the UK I went to a motorcycle swap meet near Cheltenham and saw four Honda 50 Pistons of 1960 vintage for sale. They were four at five pounds each or the lot for 15 pounds. I couldn't resist them and eagerly parted with the money. At the time I had no idea what I would use them for. On reaching home and in my favourite place ( the shed) I sat down and designed an engine around them and the three cylinder is the end result. I know it's cheating a little but it gave me the motivation fir the design. The photo shows that I do make pistons!
George.

 

[kuhncw]

George, Thanks for the information. Your three cylinder is quite a robust little engine. To me, using commercially available parts is not cheating in any way.

Your coolant piping is attached only to the cylinder head. I'm guessing the head feeds the cylinder block and then the coolant returns back through the head?

Again, interesting design you've come up with. I like it.

Regards,

Chuck

 

[George Punter]

Chuck this engine has water cooled cylinder block and head. The top pipe passes through the head and allows the coolant to start its journey around the wet cylinder liners and then up to the head and out the pipe in the side of the cylinder head. This I hope gives a more even distribution of the coolant around the cylinders especially the central one. There is a coolant pump and radiator positioned at the front of the loco.
George.

 

[kuhncw]

Thanks George. Looking at the flywheel end, intake side of the engine, is that a fuel reservoir fed by a gear pump?

Your twin cam certainly gives plenty of power take off options.

Chuck

 

[George Punter]

Hi Chuck,
Viewed from the flywheel end - on the left hand side is a gear oil pump feeding oil to the mains and big ends. On the right hand side is a small piston pump that pumps the petrol from the fuel tank ( which is below the loco chassis) into a weir - this has an over flow that returns excess fuel to the tank and gives a constant head to the carburetor. The pump works on a small eccentric cam on the end of the camshaft.
Regards,
George.

 

[bigjy]

Hi
Where can I get hold of the engine drawings
Regards