Edgar T Westbury Seal 15cc

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simonbirt

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I used the Hemingway castings ( about 10 years ago so most likely different production run) and they were on the small side of things.
Engine runs OK, think I need to increase carburetor size, the one I have is RC modified for petrol.
I have one issue, psark plug size, I made the head for the 1/4 32 long reach plugs and they work OK, but the spark plug boots barely make it over the exhaust / intake casting piece, So I have a new head to machine and drill for 10-40 spark plugs, I think those will give you a better look and will give some room.
Would be good to see some pictures of your engine.

Have you thought of making spark plugs to fit rather than a new head?

One other question, in the build notes and plan Westbury states that the firing order is 1-2-4-3. Somebody has added in red text 1-3-4-2 !!, I assume Hemingway. I am slightly struggling to get my head round the valve events, always easier when you can see the valves moving. What order does yours fire in?

Simon
 

gadabout

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Mine fires 1342, others have theirs firing 1243 , depends on how you cut the cam. I followed the build notes to how I interpreted them and that’s how it turned out, others get a different result. Doesn’t matter really as long as it runs!
 

Basil

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1342 is very traditional for a inline 4. To help with the events I always work with the rocking couples. ie Exhaust closing intake opening. That gives you the firing order very clearly. Also helps to colour the lobes so as not to get confused on what that lobe is pumping.
 

jquevedo

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In the Model Engineer July 10 1947, there is a correction note when Westbury acknowledges of the error in the firing order mixing of 3-2 in the firing order, if you followed his instructions to build the camshaft with the his process in the lathe, most likely you have ended with a 1-2-4-3 camshaft, very simple to determine once you have all pieces together.

During assembly / timing you will find the order of events and install spark wires according to the firing order your camshaft dictates.
Engine crankshaft and camshaft rotate in the same direction.
Find engine TDC for piston 1 ( front of engine). Hold crank in that position.
Rotate back and forth camshaft until you see notice the overlap in piston 4, that will set the time for the engine. You can be as complicated as you want in this step and use dial indicators and angle wheel for timing , we can write a book on how many approaches are for this topic.
At this point you install the gear to synchronize the Crankshaft and camshaft.
then rotate engine 180 degrees in Crankshaft and you will find which piston is in overlap, if it is 3 in overlap, then firing is in 2, if 2 in overlap then 3 is firing..

I have a pair of what I remember are camshafts with the 1-3-4-2 firing order ground.

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simonbirt

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In the Model Engineer July 10 1947, there is a correction note when Westbury acknowledges of the error in the firing order mixing of 3-2 in the firing order, if you followed his instructions to build the camshaft with the his process in the lathe, most likely you have ended with a 1-2-4-3 camshaft, very simple to determine once you have all pieces together.

During assembly / timing you will find the order of events and install spark wires according to the firing order your camshaft dictates.
Engine crankshaft and camshaft rotate in the same direction.
Find engine TDC for piston 1 ( front of engine). Hold crank in that position.
Rotate back and forth camshaft until you see notice the overlap in piston 4, that will set the time for the engine. You can be as complicated as you want in this step and use dial indicators and angle wheel for timing , we can write a book on how many approaches are for this topic.
At this point you install the gear to synchronize the Crankshaft and camshaft.
then rotate engine 180 degrees in Crankshaft and you will find which piston is in overlap, if it is 3 in overlap, then firing is in 2, if 2 in overlap then 3 is firing..

I have a pair of what I remember are camshafts with the 1-3-4-2 firing order ground.

View attachment 134370 View attachment 134371 View attachment 134372 View attachment 134373 View attachment 134374
Thanks for the information, very useful, as are the photographs. I am some way from needing to worry about the timing as I have the crankshaft, pistons etc to complete.

I am sure that In will be asking for more information as the build progresses. Im basking in the triumph of getting over the casting error At true moment, although it was touch and go, there is not a lot of room for the camshaft and associated bits and pieces.

Next step is to make the valves and liners.
 
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Simon, I should have pointed this out earlier, but you are moving fast. If the camshaft is made to drawing, the 1/4" tappet diameter is too small, and the inlet cam will briefly bear on the edge of the tappet instead of the face. The Seagull has a virtually identical valve train, and on mine I increased to tappets to 9/32" diameter, and increased the nose radius of the cam a trace. There is a recent discussion about the same problem with a Wallaby starting here:


Going back a bit further, I solved the camshaft keyway conundrum with a feather key let in to the taper:

 

simonbirt

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Simon, I should have pointed this out earlier, but you are moving fast. If the camshaft is made to drawing, the 1/4" tappet diameter is too small, and the inlet cam will briefly bear on the edge of the tappet instead of the face. The Seagull has a virtually identical valve train, and on mine I increased to tappets to 9/32" diameter, and increased the nose radius of the cam a trace. There is a recent discussion about the same problem with a Wallaby starting here:


Going back a bit further, I solved the camshaft keyway conundrum with a feather key let in to the taper:

Thanks for the additional information. I mocked up the camshaft tapped interaction and had a close look at the contact between cam lobe and tappet, I found it quite hard to see what was going on but think that what I have will work. If I make the tappets bigger I will run into problems at each end of the block, even with 1/4” diameter tappets, the first one conflicts with the camshaft bush and the last is only just clear of the casting. Not sure why this is so as the block and bushes are all machined as per drawing. I don‘t have the option to change the cam profile as I have already hardened it and its straight! Think I will use unhardened tappets and see how it goes, I can always make them larger if needed later.
 

simonbirt

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I thought it may be time for an update on the Seal project.
The pictures shows the progress to date. The casting difficulties are largely behind me (I hope) I had to let a piece in to the sump casting as it was so far undersize in width, but oddly oversize in length.

Machining the crankshaft was a challenge as it is very slender, took about a week, including grinding a special set of lathe tools and trying to work out how to hold the thing.
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I think I will sort out the gear drive between crankshaft and camshaft next, then have a go at the pistons and connecting rods. There is not a lot of information on the drawing for the pistons, particularly ring groove dimensions. Hemingway supplied rings with the "kit" but as yet I haven't spent much time thinking about that part of the engine. I expect I will be asking for some help at some stage from those who have built a Seal.
 

simonbirt

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Hello All,

I have had a break from the Seal project for a while, been fettling motorcycles. Now the winter is really here I am back in the workshop and trying to remember where I got to.

I have made the valves and cages, last week I made the connecting rods. Now I need the pistons. Hemingway supplied rings in the "kit" I use the term lightly. The drawing does not give dimensions for the ring grooves. I attach the drawing of the piston. The supplied rings are nominal 0.030" thick by about 0.035", fully closed they are are close to 0.625" diameter.

My question: how deep/wide should the ring grooves be?
IMG_5871.jpeg
 

simonbirt

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Thanks D and D.

I actually have a set of rings, so will use them. Just was unsure how much clearance to allow.
 

Basil

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On my 30cc Seal I made the ring groove a little narrower than the ring. I made a holder that would receive the ring in a compressed state with a little of the ring sticking out so I could dress this down slightly with wet and dry paper. I did micrometer the ring as I went to make sure I was not developing a slant. A bit fiddly to remove from the holder but compressed air worked good for this. I dressed both sides, finishing with 2000 grit. When your getting very close start rolling the ring around in the groove to see if there are any tight spots. I aimed for a nice sliding fit with just about zero clearance. I went with about 4 thou back ring clearance just to make sure the ring would never be left proud.
 

simonbirt

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On my 30cc Seal I made the ring groove a little narrower than the ring. I made a holder that would receive the ring in a compressed state with a little of the ring sticking out so I could dress this down slightly with wet and dry paper. I did micrometer the ring as I went to make sure I was not developing a slant. A bit fiddly to remove from the holder but compressed air worked good for this. I dressed both sides, finishing with 2000 grit. When your getting very close start rolling the ring around in the groove to see if there are any tight spots. I aimed for a nice sliding fit with just about zero clearance. I went with about 4 thou back ring clearance just to make sure the ring would never be left proud.
Im trying to visualise what the ring holder looks like, is it a hollow tume and piston?
 

Basil

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Im trying to visualise what the ring holder looks like, is it a hollow tume and piston?
I seem to have mislaid the one I made for the Seal but these are some I have made for larger engines. I make them in 2 pieces. Inner part and the sleeve so the OD of the ring has no chance of hanging up on a slight radius left by the cutting tool. The sleeve is exact bore size. Both are locktited together and set on surface plate to align.
I think this method also helps to take any twist that may develop when the ring is compressed.
Worked well for me.
 

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simonbirt

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I seem to have mislaid the one I made for the Seal but these are some I have made for larger engines. I make them in 2 pieces. Inner part and the sleeve so the OD of the ring has no chance of hanging up on a slight radius left by the cutting tool. The sleeve is exact bore size. Both are locktited together and set on surface plate to align.
I think this method also helps to take any twist that may develop when the ring is compressed.
Worked well for me.
Thanks Basil,

This is useful, I think I will hive it a try. The rings as supplied are not all exactly the same width, this will solve that problem.
 

simonbirt

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Thanks Basil,

This is useful, I think I will hive it a try. The rings as supplied are not all exactly the same width, this will solve that problem.
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Here is my version of the ring holder. To overcome the ring removal problem, I make the two parts detachable with a dowel pin to hold them together. It works well, although it is a struggle to get the rings a uniform thickness all over.

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Basil

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Nice! I found with mine holding the assembly very low down close to the paper and spinning it regularly. WD40 on 1000 grit/ surface plate works, but yes some practiced technique required. 👍
 

simonbirt

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I now have to make some additional rings, Hemingway supplied 8 with the “kit” some of which were distorted, one broke as I inserted it into a liner. I think while I am at it I will make a dozen, I will then have plenty of spares. The thickness and ring gap seem OK, therefore I will copy the suppled ones. Just waiting for the expensive cast iron to arrive.

I have mentioned this before, but will repeat in case anybody is thinking of ordering a “kit” from Hemingway. I would not recommend it, it is far from complete, no material for con rods, valve cages etc, no faster. The castings are poor, the drawings have numerous errors and it is expensive. If I were doing it again, I would machine it all from bar stock, having re-drawn everything minus the errors.

Despite the above, I am enjoying the build, solving problems as I go. Should soon have all the rotating bits installed which will be a milestone. Then it is cylinder head, manifold and lots os studs to make. Still not sure what to do about an ignition system or water pump, I will worry about that later.
 
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This seems odd. Normally a Hemingway kit includes all the material you need, except fasteners, but even including material to make a cam turning jig. Bronze bar for the valve cages and aluminium alloy for the con-rods should definitely have been included.
 

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