Another Westbury Seal 15cc

It has been a while as I have been occupied with model railway projects. However, I am back now to have a go at my new project. A chance conversation with Reece Cobb of the Nelson Society of Modellers and I was offered a set of castings that had been in their store room for some time, a Westbury Seal. The kit arrived today.




Thankfully it came with the drawings which will make it easier to decode the copy of the 1947 ME articles that can be found on the Hemingway website. Reading Jo's and Vixen's threads there are a number of things that need to be considered before pitching in and blindly following the Edgar Westbury instructions.  I plan to draw up as much as I can in Fusion to make sure things go together sensibly, that will also enable me to CNC mill some parts where appropriate so it may be a while before I start cutting metal

Pete

and especially for our  UK viewers

Hi Pete,

Looking forward to seeing your Seal build.  I don't know where you are hosting your photo but all we can see is a box that says "content not viewable in your region" 

Edit Jo: Imgur is no longer visible here in the UK, so Pete has attached his photos so we can enjoy his build too 

Jo

P.S. I removed the discussion about the visibility problems so it does not spoil the flow of your build 

If I may be allowed briefly to blow my own trumpet, another blog on building a Westbury engine from castings is my effort at: http://www.charleslamont.me.uk/Seagull/home.html

Quote from: Charles LamontIf I may be allowed briefly to blow my own trumpet, another blog on building a Westbury engine from castings is my effort at: http://www.charleslamont.me.uk/Seagull/home.html

Thanks Charles I'll probably need as much help as I can get, even if it is just another perspective on how to do things.

Hello Pete,

The Westbury Seal is a fun engine to build. I hope your castings are of better quality than the rubbish I got from Hemmingway. That aluminium casting was so soft and crumbly that all the studs eventually pulled out.   

Good luck

Mike

Quote from: VixenHello Pete,

The Westbury Seal is a fun engine to build. I hope your castings are of better quality than the rubbish I got from Hemmingway. That aluminium casting was so soft and crumbly that all the studs eventually pulled out.   

Good luck

Mike

I had noticed that on your thread. I don't know where mine came from but they are pretty old. The cylinder block was cast from two unmatched patterns. The boxes for the spark plugs give some indication of age.

I am going through your thread as it gives some pretty good ideas of the gotcha areas. That is why I am drawing the plans in Fusion before I start so I can get them sorted.

Pete

Hello Pete,
My castings were from the first batch after the foundry reopened following the Covid lockdown. Your kit appears to be much, much older, with hopefully nicer aluminium.

Yes, lots of gotchas in the drawings, I don't think Westbury actually built one himself. Have you found the 17/16" dimension yet? Have you noticed the cylinder head studs and some of the inlet exhaust/ manifold studs want to occupy the same bit of space?

Cheers   
Mike

Quote from: VixenHello Pete,
My castings were from the first batch after the foundry reopened following the Covid lockdown. Your kit appears to be much, much older, with hopefully nicer aluminium.

Yes, lots of gotchas in the drawings, I don't think Westbury actually built one himself. Have you found the 17/16" dimension yet? Have you noticed the cylinder head studs and some of the inlet exhaust/ manifold studs want to occupy the same bit of space?

Cheers   
Mike

I am aware of the conflicting studs problem and the protruding cylinder crowns. I've not seen the 17/16" dimension yet, or I'm not aware if I have. I am drawing in imperial dimensions in Fusion and fractional values are accepted so 17/16" will automatically convert to 1 1/16". Actually entering 17/16" when in metric mode will convert to 26.99mm

Pete

One of the less obvious gotchas is that the tappets are not large enough in diameter for the cams, inlets in particular. There are various ways round this.

Quote from: Charles LamontOne of the less obvious gotchas is that the tappets are not large enough in diameter for the cams, inlets in particular. There are various ways round this.

Here is a question for the knowledgeable. The drawings and original ME article say the firing order is 1-2-4-3 but the copy of the ME article from Hemingway is marked up 1-3-4-2!! (on the pdf page 27). Are they saying that with the camshaft manufactured as designed the firing order should be 1-3-4-2 or the camshaft should be reworked so the firing order is 1-3-4-2. What are your thoughts on this?

I have just had a harder look at the diagram below. In the relative position diagram cylinder #1 is at the firing point, both valves closed turn the crankshaft half a turn and the camshaft a quarter of a turn clockwise and cams for cylinder #3 are now in the same position that #1 were. So 1-3. Then turn the camshaft another quarter turn and now #4 are in the firing position, noting the inlet and exhaust are swapped over so now 1-3-4. Do another quarter turn and cylinder #2 cams are in the firing position so it is 1-3-4-2 as drawn.

The relevant section of the drawing



Pete

Quote from: Charles LamontIf I may be allowed briefly to blow my own trumpet, another blog on building a Westbury engine from castings is my effort at: http://www.charleslamont.me.uk/Seagull/home.html

Very nice writeup & pictures, Charles. Unless I missed it, its not clear to me how you are pumping cooling water. Can you elaborate?

Depends which way the cam is rotating, the relative positions look right for 1243 if they are going anti-clockwise

If you take inlet 1 which is cam B in the relative drawing and then look at the camshaft angle diagram. It says that the inlet will open at 175degrees of cam angle.

you would need to rotate cam B anti-clockwise for it to start opening at 175deg. If you rotated it clockwise it would start opening at about 90deg of rotation.

Then looking at Cam C that needs a further 90deg of cam rotation before that opens. so 265deg

Cam G a further 90deg so 355deg

And lastly Cam F a further 90deg so 455deg

You might be tempted to say 4 opens first as it is almost at the open position in the relative diagram, then 3, then 1, then 2 so 4-3-1-2 but I think convention always starts with No1 cylinder so keeping the order 4-3-1-2-4-3-1-2-1-2-4-3

Quote from: petertha

Quote from: Charles LamontIf I may be allowed briefly to blow my own trumpet, another blog on building a Westbury engine from castings is my effort at: http://www.charleslamont.me.uk/Seagull/home.html

Very nice writeup & pictures, Charles. Unless I missed it, its not clear to me how you are pumping cooling water. Can you elaborate?

Thank you. There will be a pump belt driven from the crankshaft. I still have not done that, but I did some research on the design here: https://www.modelenginemaker.com/index.php/topic,11615.0.html