Author Topic: 15cc Seal and 30cc Seal Major  (Read 10965 times)

Online Jo

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15cc Seal and 30cc Seal Major
« on: June 01, 2019, 08:50:51 AM »
The design for the 15cc Seal was published in Model Engineer by Edgar Westbury in February 1947. It is typical of the pre-war straight four engine designs with water cooling, side valves and a two-bearing crank. From the first article Edgar suggested that the Seal was going to be the first of a number of four cylinder model engines he intended to publish promising both 15cc and 30cc designs of side and overhead valve arrangements.
Edgar chose to design an engine based around automobile rather than marine practice as it is simpler and lends towards straightforward methods of construction.



In the UK Castings for this engine are available at a reasonable cost from Hemingway: http://www.hemingwaykits.com/acatalog/The_Seal___Edgar_T_Westbury.html and it makes up into a nice little engine:



While Edgar promised an engine in the larger 30cc size in 1950 David Braid beat him to publishing providing us with the Seal Major. Hemingway can also provide castings for this engine as well: http://www.hemingwaykits.com/acatalog/Seal_Major.html


In his original article Westbury described the machining operations for his engine and the same techniques can be employed to build the larger Major, the Major requiring a lathe of greater capacity for the machining operations.


Our casting sets for both of these engines are Orphans  :'( the Seal being further along than the Major. So you can understand the starting point it is probably best we start by investigating their 'features'  :paranoia:

Jo

P.S. About the same time as Westbury published his Seal, Elmer Wall published his 50CC four cylinder Side valve engine the 501.

« Last Edit: June 01, 2019, 09:13:09 AM by Jo »
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Online b.lindsey

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Re: 15cc Seal and 30cc Seal Major
« Reply #1 on: June 01, 2019, 02:27:31 PM »
Nice "new" project(s) Jo. Will you be building both at the same time?

Bill

Online Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #2 on: June 01, 2019, 02:34:29 PM »
Yes Bill the plan is to build both in tandem:

Status Review: Seal Major

The set of castings for the Seal Major has had less done to it than the Seal so this will be the main focus of this thread, while I am at it I will complete the Seal :)

The set of castings from Hemingway includes: Cylinder Block, Head & Cover, Sump, Bearing Housing, Timing End Plate, Timing Cover, Manifold Body & Cover, Valve Cover and the Carburettor Body. The set I have also includes Bronze connecting rods and the castings necessary to attach the water pump.



There are two variations of this design one has a Horizontal distributor driven directly off the end of the camshaft:



The other design is for a vertical distributor driven off of some spiral gears which are difficult to cut or acquire and an impeller water pump:



 :thinking: So if I want to use those castings for the water pump I will need to cut some spiral gears.


As for the Castings:
  • The main block has had its top and bottom faces skimmed flat leaving 0.7mm on the top surface to come at the appropriate stage later  ;) The block has been bored for the crankshaft and camshaft.
  • The timing cover and Timing End plate have been turned as has the Main bearing housing
  • The Cylinder head, Sump and Top covers have had their faces machined flat but are all over sized 
  • There is a 'completed' carb but also a spare body  :thinking:
  • someone has started the Manifold  :noidea: which will need checking as this design has a famous oops in that its mounting studs hit some of the cylinder studs

I also have a set of timing gears that I cut for this engine when I was making the Kiwi timing gears (Westbury must have had a ready supply of 40DP gears of 20 and 40 teeth). A new set of Japanese bearings have been purchased for the crank to run in and an nice piece of EN8 has been sat there ageing for the crankshaft and there is an off cut of some sort of steel that can be used for the flywheel 

Assuming the crankcase has been bored in line I can't see any obvious problems starting on this engine  :-X

Jo




« Last Edit: June 02, 2019, 07:12:32 AM by Jo »
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Offline Vixen

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Re: 15cc Seal and 30cc Seal Major
« Reply #3 on: June 01, 2019, 03:03:18 PM »
Hello Jo,

Two nice little engines. I have always promised to build one for myself. Well perhaps one day

The other design is for a vertical distributor driven off of some spiral gears which are difficult to cut or acquire and an impeller water pump:
Jo

HPC Gears should be able to help you with some crossed helical gears. They have a large section in their catalog offering a wide range in both MOD and DP

Mike
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Online Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #4 on: June 01, 2019, 03:06:59 PM »
Thanks Mike, I will look and see if HPC have some suitable gears for the Major.

Status Review - Seal


If you buy the castings from Hemingway for the Seal you get 10 castings: Cylinder Block, Head & Cover, Sump, Bearing Housing, Timing End Plate, Timing Cover, Manifold Body & Cover, Carburettor Body. Our set has a few more: 7 connecting rods  :headscratch: 3 pistons  :facepalm: and more than two sets of the additional castings to fit the water pump.





This engine has had a lot done to it but sadly it has not been finished hopefully we can complete it while the Major is underway.

Lets see what has been done:

  • The crankcase has be machined, liners fitted and the valve guides fitted. In fact most of it has been done
  • The Timing cover/plate have been machined (the inner plate looks to have been bored oversized and had a repair piece inserted  :-\ ) and had the mounting holes drilled/tapped and there is nearly a complete distributor and pump assembly
  • The other bearing housing has been machined and had its steel insert added.
  • There is both a crankshaft and a camshaft (and the jig on which it was machined)
  • In the little tub are the valves, the tappet guides and the valve springs

Whoever started this engine had gone a long way. I'll have to review the fine measurements of the crank and camshaft at a later stage, in the meantime where to start  :thinking: Maybe a bit of fettling

Jo
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Offline gadabout

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Re: 15cc Seal and 30cc Seal Major
« Reply #5 on: June 01, 2019, 11:41:43 PM »
Jo , I have an orphaned Seal 15cc also but not as much done as yours. Are you sure the horizontal distributor ran off the crank? I thought it ran off the camshaft, don't have my plans hand atm to check. Really looking forward to these builds
Mark

Offline Dave Otto

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Re: 15cc Seal and 30cc Seal Major
« Reply #6 on: June 02, 2019, 12:00:52 AM »
Hi Jo

Looking forward to following along with the new project/s!

Dave

Online Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #7 on: June 02, 2019, 07:11:47 AM »
Jo , I have an orphaned Seal 15cc also but not as much done as yours. Are you sure the horizontal distributor ran off the crank? I thought it ran off the camshaft, don't have my plans hand atm to check.

 :facepalm: You are right it is driven off the big gear.

Jo
« Last Edit: June 02, 2019, 07:20:05 AM by Jo »
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Offline ChuckKey

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Re: 15cc Seal and 30cc Seal Major
« Reply #8 on: June 02, 2019, 11:16:25 AM »
Older aluminium castings from Hemingway or Kirk's predecessor Woking Precision can be infuriatingly soft and gummy. I found a slow speed, no more than for mild steel, and lubrication with Rocol RTD liquid usually gave a good finish with sharp HSS tools. Paraffin, my usual ally lubricant, was not much help. 'Course, somebody else may find dry, flying carbide works.

Online Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #9 on: June 02, 2019, 03:18:03 PM »
Thanks ChuckKey, I know Kirk doesn't get his castings heat treated which would cure the gummy/sticky problem. Having had a fettle with the manifold these seem to have aged nicely and I am hopeful that they won't give me problems.

I decided to start by reviewing the manifolds, first the Seal which had its Carb mounted:



Clearly it won't fit  :ShakeHead: The answer is going to be to fettle off the bit of carb that has the air bleed in it. Hopefully the plugs will be clear when fitted  :noidea:

Both the Seal and the Major can be built either way round. I don't have this option as the timing plates have already been fitted. And someone has drilled for the water outlet on the Seal:



The next feature to think about is the bolts that attach the manifold to the Seal:



These are standard headed 7BA screws and there is no space to get the spanner in to tighten them. The options are to use hex bolts with a smaller head, slotted screws or Replace them with studs and nuts but they would have the larger hex again  :noidea:

One of the known issues with this engine is that one of the head threads crosses over one of the manifold threads in the block:



It is already drilled and tapped so it looks like it is going to stay there. And looking in the manifold it would be difficult to move the bolt holes without falling into the air gap:



This had been gunged together with Blue silicon sealant. Having removed that I found the surfaces were still a bit rough so they have been lapped flat using a piece of wet and dry on the surface plate. The carb on this looks good: the barrel is a nice tight fit and other than that solder tag  :facepalm2: which someone has tried to use as the friction spring its good to go.

 

However, the carb on the Major is a reject:



The barrel is a sloppy fit :Doh: the fuel hole in the bottom is not central so who ever made it tried making the hole in the bottom of the barrel larger so it won't suck very well. Thankfully the engine came with a spare carb casting so maybe someone realised that it was no good.

The other feature I found on the major was that someone has drilled both ends of the manifold for the exhaust  :headscratch: So were they intending on having one exhaust going forward and one backwards?

I think I need to get the major block up to the same stage as the Seal first....

Jo


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Online Alyn Foundry

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Re: 15cc Seal and 30cc Seal Major
« Reply #10 on: June 02, 2019, 03:50:08 PM »
Be quick Jo.

I noticed Surrus has OD'd on the Snickers tub.... " to the casting cupboard " !!   :)

Offline Jasonb

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Re: 15cc Seal and 30cc Seal Major
« Reply #11 on: June 02, 2019, 04:12:38 PM »
Drawings seem to show that the manifold bosses should have been spot faced flush with the tops of the ribs not recessed so that does not help with the fit of your fixings.

You could make up some bolts with taller heads if you want to keep to the same hex, or some home made flange headed bolts would look good, maybe drop to 8BA hex on those. Failing that what about turning some thick washers and using the fixings you have if they are long enough.

EDIT Thinking about it a bit more the ideal solution would be to reinstate the bosses to the correct height. So recut the counter bores with a slightly larger cutter say 5.0mm or 5.5mm to get a crisp edge and go a bit deeper then Loctite in some new aluminium bosses and finally skim them all down to one height when the Loctite has set. :ThumbsUp:
« Last Edit: June 02, 2019, 04:42:52 PM by Jasonb »

Offline ChuckKey

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Re: 15cc Seal and 30cc Seal Major
« Reply #12 on: June 02, 2019, 04:18:22 PM »
You can get one-size-smaller BA nuts at EKP Supplies (among others).

Online Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #13 on: June 02, 2019, 05:41:12 PM »
Be quick Jo.

I noticed Surus has OD'd on the Snickers tub.... " to the casting cupboard " !!   :)

Thanks Graham... So much for us sharing the tub :ShakeHead: While I can remind myself what is in the cupboard I dare not take any  :hellno: He will make my life so difficult.


I am still thinking about the fixings.... you know how much I love my studs  :embarassed: and I was considering giving them  flanged nuts  :-X

Jo
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Offline Roger B

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Re: 15cc Seal and 30cc Seal Major
« Reply #14 on: June 02, 2019, 07:18:27 PM »
Two interesting engines  :) I will be following along :wine1:

I know some of ETW's engines were designed as working engines like the Aero engines and the 1831/Wallaby. Were these also designed to power something or just for display?
Best regards

Roger