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Westbury Wyvern IC Engine - Advice Please

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Nick T01/04/2018 17:01:52
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I have gained just over two years workshop experience building a Sweet Pea loco rolling chassis, cylinders etc., and I am thinking of building Westbury's Wyvern IC engine.

I won't bore you with the details of why am stopping work on the Pea but would be grateful for advice on whether I would have the ability to take on a Wyvern build and if there any issues that I should be aware of. Many thanks. Nick

PS: Workshop kit includes Tom Senior Mill and Boxford lathe.

Edited By Nick T on 01/04/2018 17:02:50

Neil Wyatt01/04/2018 18:53:43
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I'm sure it would be within your capabilities now.

Take a step at a time and ask if you are unsure.

Neil

John Purdy01/04/2018 19:17:11
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Nick

Check out my post in the "Drawing Errors and Corrections" section of this forum. I built the Wyvern from the Hemingway set about two years ago and found it a fairly strait forward build, but there are a number of errors and problems in the drawings as noted in my post.

John

Edited By John Purdy on 01/04/2018 19:18:37

John Purdy01/04/2018 21:44:14
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Nick

Further to my last, there was a 4 part series in ME in 2004, issues 4229, 31, 33, and 35 featuring the building of the Wyvern that I found useful. I always find it interesting to see how others approach various machining operations, and sometimes the light goes on, why didn't I think of that???.

John

Nick T02/04/2018 06:53:23
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Thank you Neil & John for your advice and encouragement. I did see your errors posting a while back John and I will go back and check it again. I will probably take the plunge soon and maybe start a progress thread. Regards. Nick

not done it yet02/04/2018 09:52:30
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Do all the Hemmingway kits assume no more kit than a lathe? Or was it just the Westbury plans which were like that? With a mill at one’s disposal, the machining options are much much greater.

JasonB02/04/2018 10:20:37
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Most of the designs date back to when the majority of home workshops only had a lathe so a lot of engines and tooling are designed to suit being made on a Myford which was the most commonly used lathe. This is why a lot of stationary steam engines have 9" flywheels which fit comfortably in the Myfords gap. having a mill will certainly make things easier but is not essential.

It is always a hard question to answer about whether someone will be capable of making something without seeing their previous work. If you loco chassis all runs smoothly on air then you should not have any problems with an open crank engine, if on the otherhand you have put it to one side as it is twisted, tight and won't run on 100psi of air then maybe you will also have problems with the Wyvern.

Nick T02/04/2018 21:15:55
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Thank you Jason. Nick.

ian j29/07/2018 19:33:56
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Early this year I bought a part completed Wyvern engine and I have now got around to finishing it off.It came with a set of plans and the Westbury ME construction articles apart from 1st May 1963 page 16, can anyone help with this missing page?

I have the ME magazines with Peter Rawlinson's build articles in which he mentions a letter in ME 3300 1st July 1966 which he recommends reading,can any one help with this as well?

In John Purdy's list of drawing errors he says the timing drawing should be revered to give CCW rotation, is this the normal direction as I have seen videos showing CCW and CW rotation?

Also I cannot see on the drawings any details of the cam shaft?

Thank you

Ian

Edited By ian j on 29/07/2018 19:35:47

JasonB29/07/2018 19:45:08
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I can dig out the 1963 if no one else can easily lay their hands on it.

 

This is the 1966 letter, click to enlarge

wyvern balance.jpg

Most open crank engines have the top of the flywheels moving away from the cylinder, makes it easier to start by flicking the flywheel over by hand.

camshaft is just 1/4" dia, PGMS or Silver steel.

Edited By JasonB on 29/07/2018 19:51:19

ian j30/07/2018 07:45:42
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Jason.

Thanks for your prompt reply and help (again)

If you could look up 1st May 1963 page 16 it would be greatly appreciated

Roderick Jenkins30/07/2018 16:15:39
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Hi Nick,

it's worth bearing in mind that the original design for the Wyvern was based on using bronze and cast iron castings. Presuming you are thinking of getting the castings from Hemingway, in which case the c.i. will be replaced by ally, except for the flywheels. This is not really a problem except that the exhaust valve seat is directly in the head casting - fine in c.i. but not favourite in cast ally. Most of us who have built Wyverns have used a separate valve insert for the exhaust that is similar to the inlet. If you want to see how many mistakes it is possible to make when building a Wyvern you might find my build log over on ModelEngineMaker instructive **LINK**. You might have to register to see the pics. It turned out OK in the end though.

HTH,

Rod

JasonB30/07/2018 17:23:10
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Here you go Ian, page 16. Click to see it bigger or PM me an e-mail if you want it sent.

wyvern p16.jpg

ian j30/07/2018 19:35:46
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thanks again for your help Jason.

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