Edgar T Westbury Seal 15cc

[simonbirt]

Hello all,

I am thinking about building the Seal 15cc 4 cylinder side valve, designed by Edgar T Westbury in 1947.

Before ordering an expensive set of castings I thought I would buy the plans and make what is perhaps the most challenging part, the cam shaft. So far I have made the turning jig as per Westbury's instructions (see photo) and turned the blank. Next task is to turn the cam flanks and then profile the rest of the cam. I think I may mill the bottom rather than “nibble” it away as Westbury suggest.

As you can see on the drawing there is a woodruff key to secure the camshaft gear to the shaft. I wonder if anybody has an idea how to cut this? It is only about 0.125” diameter, making a woodruff cutter this small may be challenge me thinks.

 

[Vixen]

I don't think Westbury ever built the 15cc Seal himself. Certainly the numerous erors in the 1947 drawngs have never corrected, to this day.
The 0.125" diameter woodfuf key is an absurd idea. Instead, I drilled the shaft and fitted a 2.0 mm pin instead of that impossible woodfuf key. You will also need to consider how to cut the corresponding keyway in the gear wheel. That may govern the diameter of your pin.
Mike

 

[simonbirt]

I don't think Westbury ever built the 15cc Seal himself. Certainly the numerous erors in the 1947 drawngs have never corrected, to this day.
The 0.125" diameter woodfuf key is an absurd idea. Instead, I drilled the shaft and fitted a 2.0 mm pin instead of that impossible woodfuf key. You will also need to consider how to cut the corresponding keyway in the gear wheel. That may govern the diameter of your pin.
Mike

Thanks Mike,

You mention errors, I found the first in the turning jig drawing, it shows the jig about an inch too short.

I would be grateful for any information on the errors you encountered.

Simon

 

[Vixen]

Simon,
I did not make a list of errors. most are self obvious.The one I liked best was a dimention of 2 9/8" on the crankcase cross section.
I redrew the parts with decimal inches instead of fractons which sorted most things out.
Mike

 

[gadabout]

If I remember correctly when i built my Seal 15 cc that the cam jig was an issue because when you moved the pointer to cyl one the pointer covered the centre hole , think that was right….

 

[Basil]

On the 30cc Seal Major I just finished I machined and lapped the cam and sprocket and found it not necessary to use any type of keyway. This also allows you to fine tune the cam timing as you wish. I did change the intake/exhaust manifold bolt pattern so as not to run into the head bolts.

 

[jquevedo]

One issue I found while building mine around 8-10 years ago was the space in the area where the Tappets are, specially the depth and height of the square box in the area where you have the tappet adjusters, make sure you machine to the right dimensions, very little room there for the valve lash adjustment.
As mentioned before, I have not key-way in the camshaft and that has not presented a problem, nice fit, friction and a nice brass nut did the job.

 

[Basil]

Yes had to clear the tappet box out as you can see. Also the plugging of holes to position the manifold bolts in a lower position at the head stud location. Luckily I had not drilled the block when I notice the issue.

 

[simonbirt]

If I remember correctly when i built my Seal 15 cc that the cam jig was an issue because when you moved the pointer to cyl one the pointer covered the centre hole , think that was right….

That is correct, but easy to get arround, lock camshaft move pointer to other 0, then remember to move it back.

 

[simonbirt]

Decided to go ahead and order the castings for the Seal following the successful completion of the camshaft.

The castings are a disappointment, the sizes are a long way from nominal. The main block is oversize and required a lot to be machined off the ends. The head was under nominal as was the sump. Hemingway have no other castings, this being the last, Kirk at Hemingway has promised to send me a new head casting in a month or so. The photo shows how much material had to be removed to get the correct width on the block and keep all the cored holes symmetrical.

My plan is to blend all the machined faces and then bead blast all the bits that should be cast to make it look good.

I have agree with others about the errors on the drawings, which is poor considering they have been arround since 1947. The casting and materials kit is not cheap and I expected better. Other things I have had from Hemingway have been much better.

There is a lot of missing information on the drawings, for example no dimensions given for piston ring grooves, or exact piston clearance.

I am sure that I will be seeking advice from the knowledge base here as things progress.

 

[deverett]

Just a thought Simon: As a public spirited gesture and an aid to future purchasers of the castings, would you give Hemmingway a list of the errors you find?
I would not be a beneficiary, by the way!

Dave
The Emerald Isle

 

[simonbirt]

Hello Dave,

Yes I will, it may be a long list.

Simon

 

[Weldsol]

Decided to go ahead and order the castings for the Seal following the successful completion of the camshaft.

The castings are a disappointment, the sizes are a long way from nominal. The main block is oversize and required a lot to be machined off the ends. The head was under nominal as was the sump. Hemingway have no other castings, this being the last, Kirk at Hemingway has promised to send me a new head casting in a month or so. The photo shows how much material had to be removed to get the correct width on the block and keep all the cored holes symmetrical.

My plan is to blend all the machined faces and then bead blast all the bits that should be cast to make it look good.

I have agree with others about the errors on the drawings, which is poor considering they have been arround since 1947. The casting and materials kit is not cheap and I expected better. Other things I have had from Hemingway have been much better.

There is a lot of missing information on the drawings, for example no dimensions given for piston ring grooves, or exact piston clearance.

I am sure that I will be seeking advice from the knowledge base here as things progress. View attachment 133819

I decided to machine my Sealion engine from solid as a lot of the parts that were available as castings some of them shown in ETW's writings were to be machined all over (plus it was a lot cheaper )

Re the drawing errors ( these seem to be on all ETW's engine drawings) I have spoken to Kirk ( relating to my engine) and he said he was going to sort them out when he Digitises / and does dual measurement inch / metric but when he gets round to doing it I don't know ( that was over a year ago)

Paul

 

[gadabout]

When I built my Seal 15cc the block was way too big , over 1/4” too long. I decided on mine to make sure the dipstick boss was in the centre of the block as the dipstick itself sits in between the crankshaft webs, this made the cored cylinder holes offset but they cleaned up fine. I was concerned that the dipstick might clash with the crank webs.

Mark

 

[Charles Lamont]

Remember these are small sand castings made commercially in small batches. Don't expect the accuracy of investment castings. It is almost always possible to find a whole part inside, but it sometimes takes several iterations of a thorough survey of the casting followed by tentative machining of temporay datum surfaces.

 

[simonbirt]

Remember these are small sand castings made commercially in small batches. Don't expect the accuracy of investment castings. It is almost always possible to find a whole part inside, but it sometimes takes several iterations of a thorough survey of the casting followed by tentative machining of temporay datum surfaces.

Hello Charles,

I agree, I think a sculptor who was asked how he sculpted a lion replied “ I simply chip away all the bits that aren’t lion” This is how I feel with the main Seal casting. There is precious little room on the block for all the bores, valves and studs. It has taken me days to try and work round the casting error.

I tried to use the crankshaft centre line as datum, as shown on the drawing, if I did this the valve guides would not be over the camshaft centre and would clash with the head studs. The other problem is that the sump, head and cover are all too small; looks like the foundry had an off day.

The irony is that I decided to go for a model using castings after the last project that was all from bar stock. I thought this would be easier.

I expect I will work out a solution. Probably should have rejected the castings at the outset and built something else.

Simon

 

[simonbirt]

Here is a picture of the sump casting on the block casting the side out of shot is lined up. The head and cover are a similar fit.

 

[simonbirt]

Here is a picture showing progress on the Seal. It has not been easy due to the casting being so far out. I did think that I was going to abandon the project after I spoke to Kirk at Hemingway, he told me that there was a problem with the patten which hew plans to address, I was unimpressed.

Long story short, I had to move everything over from the center line by about 1/16” which put the cam gears out of alignment with the camshaft, which in turn meant that the cam gear cover would not fit and so on. Finally after a couple of days thinking, I realised that I could shorten the tappets by the same amount and thus get everything to line up. Yesterday I bored the holes for the camshaft bushings and all seems well.

 

[Basil]

Very nice work. I found the camshaft to be the toughest part to get my head around partly because I had to change the lobe and lifter configuration .
Had to make two after one was unusable after heat treating.

 

[jquevedo]

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.