The project featured on this page was built over a one and a half year period in the Craftsmanship Museum machine shop. We have provided more photos than normal as a teaching experience. Not every viewer may want to enlarge every photo, but those interested in learning about building engines will find doing so instructive and, hopefully, inspiring.

The Internet Craftsmanship Museum Presents:

Building a Seal 15 cc IC engine

A group project with parts made by model engineers around the world

(For "First Pop" of the engine, June 21, 2007, see bottom of page for videos.)

Here is the unmachined casting set along with a photo of the finished engine from the cover of the September 2nd, 1954 issue of The Model Engineer magazine. Joe Martin started the project some time back, having made the crankshaft and connecting rods. Now you can help finish the project and be part of the list of model engineers who contributed when the finished engine is displayed in the Craftsmanship Museum in Vista, CA. (Click on photo for larger image.)

Talented Industrial Designer Charlie Tomalesky has volunteered his talents to help turn the 1940's hand drawn Seal plans into electronic form so that he can do 3D CAD presentation drawings of the parts and assemblies. Above is the 3-view drawing and a logo medallion he came up with for the foundation. Charlie is obviously highly skilled with his 3D presentations, and we will be featuring more of his drawings of the Seal on this site as he sends them in. To see more of his work, visit http://www.bright.org.uk/ and click on the magazine cover called "Computer Images." He has also sent us some images of Harley and Rotax engines that are superb pieces of artwork. If you need drawing work done for your project, you can contact him at charliet58@hotmail.com. (Artwork: C. Tomalesky. Click on plans to view a larger image.)

Download a copy of the Seal Engine Specifications and a photo of the finished engine: CLICK HERE (PDF file, 1.1 Mb)

Download a copy of the build team plaque: CLICK HERE (PDF file, 1.1 Mb)

Engine Specifications

Designer: Edgar T. Westbury (designed in 1947)

Type: 4-cycle, water cooled, inline 4 cylinder

Size: 6.75" L x 4.75" W x 5.25" H

Displacement: .84 cu. in. (13.8 cc)

Bore: 5/8"

Stroke: 11/16"

Carburetor: M&H Variable Venturi (modified)

Ignition: ProSpark electronic with Hall sensors and rare earth magnets, Rimfire long reach spark plugs

Fuel: White gas

Started: July 25, 2006 — First Run: July 21, 2007

The Seal Engine Project—How you can be part of the build team!

The Joe Martin Foundation is beginning the construction of a 15cc internal combustion 4-cylinder engine that will eventually be displayed and run as part of the museum's collection in Vista, CA. We have a casting kit, a set of plans and Tom Boyer to run the museum's shop and act as both machinist and job coordinator. We invite model engineers from around the world to participate in this project with us. Let us know what your talents are and what parts you would like to help build. We need everything from simple parts to complicated parts like a distributor or carburetor. We will be glad to mail out dimensioned plans for the needed pieces to those who would like to make parts for the engine. Once completed, the engine will be displayed along with a credit list noting the names of all who participated.

If you have questions or comments, contact shop foreman and project manager Tom Boyer.

Phone: (Tuesday through Friday, 9 AM-3 PM, Pacific)--(760) 727-9492

e-mail: mecm@craftsmanshipmuseum.com or tom@craftsmanshipmuseum.com

The completed Seal on its final oak display base. A US Quarter and a 1 Euro coin are shown for size comparison. A plexiglas dust cover protects the engine when it is not being run. (Click photo to view larger image.)

A list of parts available for construction

All parts have now been assigned. You are welcome to follow the project to completion by watching the updates added to this page often. The popularity of this project has assured that we will start another group build soon after this one is finished. Watch this web site for future projects and get involved early to assure your participation.


Overall engine cross-section for referenceCLICK HERE

The Build Team

A US Quarter Dollar coin is used for size reference in some part photos. (Click on any photo to view a larger image.)

Tom Boyer, Escondido, CA

Tom is the museum shop foreman and resident craftsman. He is machining all the castings and doing final assembly. He also made the aluminum engine display base, piston sleeves, exhaust pipe, fuel tank and many small fittings and parts as needed.

Engine progress as of 2/4/07

Joe Martin, Oceanside, CA

The museum's founder, Joe created a machine and a program to grind the camshaft on a specially modified Sherline CNC mill. Joe also made the crankshaft and helical gears for the distributor.

Helical distributor gears after hardening.

Karl Rohlin with sons Taylor and Dakota, Wildomar, CA

Taylor and Dakota made the brass oil dipstick after verbal instruction from their father Karl. Karl is the shop foreman at Sherline's production facility. He also honed the cylinder sleeves to size.

Pam Weiss, Vista, CA

A Sherline factory CNC machinist and machine repair technician, Pam made the camshaft blank, timing gear, camshaft bushings, valves, valve liners and adjusting nuts. Pam is also just completing a running Silver Angel hit-n-miss engine designed by Bob Shores among other projects that range from a Bill Smith clock to a 1/2 size Gattling gun, a Snow IC engine and a 1/4 size Offenhauser engine.

Pam's cam blank after grinding and the valves and valve parts ready for installation.


Fred Smittle, Oceanside, CA

Fred is making the brass flywheel and also a special brass 12-sided nut to hold it onto the crankshaft. Fred is a former tool and die maker and CNC instructor and is also a technical representative for Sherline.

"Practice" flywheel attached to engine for testing and final polished flywheel ready for installation when the engine is done.

Jim Clark, Billings, MT

A former high school shop teacher, Jim runs Clark Precision Machine, a business that buys and sells machine tools old and new, small and large. Jim is working on the main body of the carburetor as drawn on the Seal plans.

(Work in progress)

Jerry Kieffer, DeForest, WI

Jerry is our resident expert on building small IC engines and is acting as consultant, particularly in the area of distributor and carburetor—two of the most difficult parts of a small engine to get right.

Ralph Cooney, Forest Grove, OR

Ralph is a long time friend of Joe's and a superb craftsman when it comes to small parts. The splash shield inside the pan was designed to be bent from sheet metal. Ralph used EDM to machine first an aluminum test piece and then the final part from solid brass. It seems a shame to hide it inside the engine.

Ron Chernich, Australia

Ron has long been involved in building small engines and hosts a wonderful web site on the subject. (See www.modelenginenews.org.)  He built the pistons and rings and fitted them to the piston sleeves.

Ron's piston rings and the fitting to help install them.

Final pistons with rings plus an extra sleeve and piston just in case...

Frank Hoffman, Heflin, AB

Frank is a long-time machinist (now retired) and CNC expert. He built the distributor body and cap to Joe Martin's new design. He also made the gudgeon pins and pad ends. The photo at the left shows Frank with a Sherline CNC machine for which he has developed a 4-sided "tombstone" to make multiple parts. The second photo to the left shows a test CNC tool path for the fixture.

Frank's distributor body with the cap on and with it off.

Steven Lang, Columbus, MI

An employee for GM, Steven has been interested in model engineering for years. He came on the project late but wanted to become involved. He built brass flanges (glands), bushings and barbed water line fittings.

Robert Rosenfield, Henderson, NV

Robert is a Sherline CNC machinist who has made some amazing small superchargers for minibikes. On this project we put his CNC skills to work on the water pump impeller and housing plus the pump bracket.

Tom Egan, Los Angeles, CA

The original bronze connecting rods had become warped over the years. Joe had straightened and machined them years ago, but the internal stresses apparently came back to haunt them. Ron built beautiful new ones from aluminum.

Charlie Tomalesky, VT

Charlie is a world-class industrial designer with a talent for design and 3D computer rendering. He did color 3D art of each piece and assembled the drawings into a complete 3D cut-away. See some of his other outstanding design work at http://www.stratacafe.com/member.asp?ID=8262 .


Just a few of many samples.

Larry Simon, Carlsbad, CA

Larry is the Foundation's museum volunteer shop and tour guide on Mondays. He made the ignition contacts for the distributor and rotor center contact.

(No photo provided) Ron Reiter, Fallbrook,

Pump shaft

Duarte Cabral, San Diego, CA

Duarte Cabral is an electrical hardware design engineer, and among his noted accomplishments is the development of the ProSpark ignition system that is used by, among others, the US military. We are using a varient of it on the Seal. Duarte's expertise was put to good use on July 7th when he, Tom and Joe met in the museum shop to make sure everything was ready for the first running. After some testing and adjustment, he pronounced the engine "ready to run," at least as far as the ignition goes.

The Seal is seen in test mode with one of the spark plugs grounded to test for spark. Dychem on the flywheel is marked to confirm the timing positions. This pretty much the final big test the engine had to pass before it is test run. Now all it needs is a fuel tank.

Craig Libuse, San Marcos, CA

Craig maintains the web site, provides takes the photos for this page to document the project and is co-ordinating the program and keeping the builders and public informed on progress. He is also making the maple base the engine will be bolted to for its first run.

The completed engine on Craig's oak display base. A plexiglas cover protects the engine from dust when not being run. Electrical components are now hidden beneath the base.

Click on any photo above to view a larger image.

Watch for the Foundation's next building project and get your name on the list early in order to be a part of the build and have your name listed on the plaque by the finished engine.

Plans and casting kits available for the Seal and other classic British engines

If you’d like to build your own Seal, castings and plans are available from Hemingway Kits (www.HemingwayKits.com) in the UK. They stock kits to produce 10 of Edgar Westbury’s most famous engines from the 40’s, 50’s and 60’s alongside the world’s most comprehensive catalogue of workshop accessory kits. If you need more information you can e-mail info@hemingwaykits.com.

NOTE—ERRORS IN THE PLANS: Despite the fact that the plans have been around for over 60 years, there are several errors in the original plans that have never been corrected. Some of the dimensions do not add up properly--and one even has a fraction of 9/8" listed! Also, two manifold studs line up perfectly with head studs, making a special fix necessary. When the project is complete we will add to this site a list of known issues we discovered when building the engine.

Old Model Engineer Articles on building the Seal engine

Model Engineer magazine in England published a 13-part article by Edgar T. Westbury starting with the February 9, 1947 issue. Because of copyright issues we cannot republish those articles here. We do, however, now own a complete collection of Model Engineer magazines going back to the first issue in 1898. As a library, visitors have access to viewing these issues and are allowed to copy a portion of any issue for their own personal use. We do not have a complete article index and do not have the resources to look through thousands of issues for a particular subject, so you would need to know the issue or issues you wish to view for articles other than the Seal build. It is often the case that the plans published in Model Engineer are actually more complete than the original plans published when the kit was designed, and the comments from the builder can be most helpful in finding and fixing problem areas before you get to them. For example, we learned from the article that the firing order for the Seal as published in the plans was actually incorrect.

Here are photos of the Seal engine in progress:

(Click photos to view larger images.)

The first cast part has the back surface flattened on the lathe. The engine will require many parts custom made from bar stock as well. We invite other machinists to become a part of this project. Participants will share in the satisfaction of seeing the finished engine run in a video on this web site. (7/25/06)
The timing cover is machined flat and the mounting holes are drilled using a rotary table
Timing cover holes are transferred to the block, drilled and tapped and then the cam positioning hole is bored to size in the cover. (8/28/06)
The crankshaft, pistons and rods are seen here in relation to the 3-view drawings thanks to very creative artwork by industrial designer Charlie Tomalesky.
Another of Charlie Tomalesky's 3D CAD drawings adds the valves and valve springs to the driveline.
As of October 4th, 2006 the block and manifolds are coming along nicely in our shop. Pam Weiss has the camshaft and timing gear well along and Joe Martin is testing a program to grind the cam lobes on a Sherline CNC milling machine.

FOLLOWUP NOTE: We modified the cam drawing to match the firing order published in the plans. It turns out the drawing was correct and the listed firing order was wrong. An old article in Model Engineer magazine by designer Edgar Westbury himself explained the error but we learned of it too late. Therefore, our firing order is actually different than what Edgar originally intended, but it runs fine.

Charlie Tomalesky's latest drawing incorporates the camshaft into the driveline.

The drawing from 10/16/06 adds the block with a ghost view of the pistons, valves, crank and cams inside.

Joe's CNC cam grinder works! Pam Weiss's cam blank was ground perfectly using Joe's new CNC grinder.  Shown also are the parts that have been completed as of 10/25/06, including the cast parts machined by Tom, Joe's bronze connecting rods and Pam's cam, valves, lifters and lock nuts. Note also the sandblasted aluminum engine stand Tom machined.
Ralph Cooney outdid himself on this one. The oil pan was made from a solid billet of aluminum using EDM (Electrostatic Discharge Machining) to vaporize the unwanted metal. The plans called for sheet metal with machined pieces fitted to it and attached with screws. This is a much more elegant solution, but how many people do you know that have access to an EDM?

The second pan was provided by Ralph made from brass. He said the drawings by Charlie Tomalseki made it look so good in brass he felt he just had to make a second one to live up to the drawing.

Robert Rosenfield--the same Robert Rosenfield who made the supercharger shown on the CNC PROJECTS page on Sherline's site-- seemed the natural choice for the impeller and pump parts. Here is his drawing and some of the parts for the water pump. The final version of the impeller is being cut in brass--the aluminum one shown is a test piece.

The second photo shows the finished pump housing (lower left) and the brass impeller along with a couple of the fixtures Robert used to make the parts.

The four cylinder liners or sleeves were completed by Tom Boyer and Honed to exact size by Karl Rohlin. The 5th sleeve (with red mark) was the setup part. The sleeves were shipped to Australia on 11/8/06 so that Ron Chernich can make the pistons and fit the rings to the sleeves before returning them.
Charlie Tomaleski's digital engine is coming along nicely. Here we see the pump and ignition system added as of 11/08/06. Charlie has rendered the block as if it were made from glass so that the internal components can be seen.
Here is the block with Pam Weiss's head bolts--all 15 of them--in place. In the foreground are the two halves of the manifold which Tom is currently filing so the edges match. (11/21/06)
Joe Martin is seen sitting in front of the Sherline CNC mill setup he used to produce the spiral gears for the distributor. He cut them in brass, made a few tweaks to the program and setup and  then cut the final set in steel. He's holding the just-completed set in his hand, and they came out great!

The second shot shows a close-up of the two finished gears after heat treating, which explains their dark color. The third and fourth photos show Tom Boyer lapping in the gear teeth using diamond lapping compound. The milling machine spins the vertical gear is it runs in the horizontal gear which is held in a fixture. Lapping compound is applied to the spinning gears by means of a cotton swab. The final photo shows the finished gear blanks after lapping. A US Quarter dollar coin shows their small size.

The Seal block is seen with some of the completed parts and again with the camshaft installed. (12/05/06)
(L) Ron Chernich just sent this photo from Australia of his fixture and the piston rings ready for heat treating. (12/6/06)

(R) Ron has finished making the pistons and rings and they are on the way to the USA for assembly. He sent along this nice shot of the pistons, rings and fixtures laid out on his drawing. (1/4/07)

Tom has finished and installed the bronze valve guides and is working on the manifold studs. A design fault in the engine that has been around since 1947 causes two of the mounting studs that occur 90° from each other to line up. It's amazing that a kit that has been out for 60 years still hasn't addressed this problem, but it's still in the drawings that way. Tom is using a tip by someone who has already built the engine to make an oversize base for two of the studs to overcome this problem. This will put more threaded area in the minimum amount of depth we have available so that sufficient torque can be put on the stud when mounting the manifold.
Karl Rohlin's sons Taylor and Dakota did a nice job on the brass oil dipstick. Here it is ready to thread into the block.

The second shot shows some of the beautifully made parts that await assembly. This project is coming along nicely. The hard parts—distributor, carburetor and final assembly are now under construction, but with the talented group we have put together, there should be nothing that can't be overcome. We also think we have figured out a way to webcast the first running, so stay tuned for a "first pop" date and time.

The M&H Variable Venturi carburetor was designed by Joe Martin and Carl Hammons years ago for use on radio controlled model engines. The adjustable venturi will make it easier to tune and run this engine than the carburetor designed for it in 1947. For now Jim Clark's stock carb build is on hold until we can try this one. (2/20/07)

Here is how the M&H carburetor works. Unfortunately, the original plan drawings were lost many years ago. All that remains are these cutaways drawn by Craig Libuse in the 1980's. (Click on either to enlarge.)

Tom Boyer installs the valve springs and adjusting nuts as the eight valves go into the block.
The pistons and rods assembled to the crankshaft.
The crank and pistons installed in the block. One ring broke during installation, but luckily Ron Chernich supplied an extra piston with rings, so we had a spare.
The assembled short block ready for a test run-in.
VIDEO 1 (5 Mb)

VIDEO 2 (3.4 Mb)

First run-in, 3/28/07

At left are links to two AVI video clips showing the short block being run in using a Sherline lathe as a drive. Tom has filled the crankcase with mineral oil and the motor is being run at low RPM for a period to break in the wear surfaces and make sure everything turns freely. As you can see, it spins fine!

HINT: It might work better on some slower Internet connections to save the file to your desktop before trying to open and run it. It will play smoother directly from your hard drive. To save, right click on the link and select "Save Target As" to save it to your computer. It can take up to a minute or more to save a file as large as 5 megabytes.

Heat Treating the Camshaft—Larry Simon documented the occasion with these photos while Pam Weiss and Tom Boyer heat treat the cam to case harden it. They are using the heat treating oven in the Sherline factory to heat it in a crucible filled with Casenite and a bucket of water to cool it down. The cam is shown after heat treating in the final photo. Two cams had been ground. The heat treating process put a slight bow in both. After trying to straighten the first one and breaking it due to its brittleness after hardening, it was decided to simply leave a slight bow in the second one rather than breaking it too. The slight variation in valve lift due to the warping would not have a major effect on the running of the engine.  (4/13/07)
As of May 10th, 2007 the engine is nearing completion. Still to be completed are the working parts of the distributor and spark plug leads. A decision by Joe is pending as to whether to replace the water pump with an oil pump.
A top view of the engine shows the stinger exhaust pipe Tom designed and turned from aluminum. The second view details the M&H carburetor (Martin & Hammons) designed by Joe in the 1970's for model aircraft engine use. It features a variable Venturi of Joe's design.

The third photo shows the front of the engine with distributor in place and water pump installed and plumbed.


The latest addition to the Foundation shop is a Z-Corp 310 3-D printer capable of doing rapid prototyping. Our plan is to someday be able to take plans produced from 3D scans or drawn in a 3D drawing program and produce cast engine blocks and other kit parts for engines that are not now available. Here Pam Weiss helps sales rep Saul Hernandez hook up the machine for an initial test part.

A second photo shows the Seal and on the right is a sample model V8 produced in the 3D printer.

The engine components as of June 6, 2007. Tom had the engine apart anyway, so we laid out all the significant parts for a photo, as once the engine is buttoned up for the final time, nobody will see most of the nice work done on these parts.
During final assembly, Tom sets the valve timing. A degree wheel is fixed to the flywheel. A dial indicator shows when #1 piston is at Top Dead Center. A pointer is set to the TDC mark on the degree wheel and the engine is turned over and the cam adjusted so the first valve is fully open at 250°. An second indicator on the valve shows when it is fully open.
On Saturday, July 7, 2007, Duarte Cabral stopped by to help Tom and Joe confirm that all is well with the design and timing of the ignition. After several checks all agreed there was a good spark. We now have compression and we have spark at the plugs, so if we can just get fuel into the cylinders the engine should run. Tom is building a gas tank this week.

FIRST POP: We have tentatively scheduled Saturday, July 21, 2007 as the day for the webcast of the first pop of the engine. Stay tuned as we confirm that we have the proper equipment and computer setup to get the webcast on the Internet. Once we get a confirmed test that the broadcast will go through, we will set a firm time for the webcast and publish a web address. Matt Falkman is working on it and should soon have us up and running.

July 18, 2007—The engine is mounted on a new (temporary) Maple base. Tom has made and mounted a spring-loaded throttle arm that includes a dial idle adjustment. On the back, Duarte's ignition module is now housed inside a machined finned aluminum canister. Eventually some of these components will be hidden underneath the final display base, but for the first run they are exposed in case they need to be accessed. Tom is finishing up the fuel tank and lines. We're almost there!

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FIRST POP—July 21, 2007

10:40 AM: Tom is nervous and ready.

10:44 AM: Joe readies the engine

10:45 AM: Tom engages the drill motor. The camera shows the picture that was supposed to be going out over the webcast. It seems that part of the exercise did not work at all. Our apologies to those who tuned in and were not able to see the event. We are still trying to figure out why that didn't work.

VIDEO: First Pop

VIDEO: 2nd Pop

VIDEO: 3rd Pop

Scott Wolf captured the first firing of the engine. With started drill removed it is puffing away  on its own, sounding much like a little Offenhauser. On the first and second tries it ran for about 5 seconds. From there on things went downhill, and everything we tried seemed to make it worse.

The verdict: Close, but no cigar. We had Champaign chilled and waiting but never got to open it. There is still more work to be done before it is a smooth running engine. Anyone who has tried building an internal combustion engine from scratch will probably not be surprised by this, but a word of congratulations should go out to all those who participated in this project. No parts failed and all fit together well. From now on it is just fine tuning. Click on the video links to join us for the engine's first attempt at life.

VIDEO: Full Run, 8/07

NOTE: This is a .WMV file of about 2 Mb in size. If you don't have a fast Internet connection, the file will play smoother if you right click on the link and use the "save as" command to save it to your hard drive. Then open it in Windows Media Player and run it from your hard drive.

SUCCESS—Round One!

Within a week or so after the first attempt to run the engine, Joe and Tom had the kinks worked out. Cleaning and regapping the spark plugs, raising the gas tank and a few other minor adjustments were all it took to turn it into a good running engine. Craig was on vacation during that time, but upon his return Tom fired the engine up for this video. As you can see, it now starts with a twist of the flywheel, idles at less than 1000 RPM and revs freely. It does pass a little oil, but keep in mind there are two compression rings on the pistons but no oil rings, so this is normal.

Round Two

Joe and Tom will continue to refine the fuel system to improve running characteristics throughout the rev range. Craig will build a more appropriate base for display in the museum and design a plaque to honor all those who contributed parts.

What's Next?

We are now ready to move on to the next engine. Watch for details soon. This next project will also be a group build, and we would like to accommodate those who were unable to get in on the Seal project.

Post-completion Engine Updates

Tom demonstrates the engine for a hotrod club from Fallbrook, CA that stopped by for a museum visit in December, 2008.

The engine now has several hours of running time on it, mostly in 1 to 3 minute runs. In mid-November, 2007 when Tom was test running the engine it seized. The rod on #1 cylinder galled the crankshaft causing the engine to stop, but no other damage was done. Tom disassembled the engine and cleaned and polished the crankshaft journals and rod bearing surfaces. The galling was insignificant enough that it could be polished out. It has been determined that the small hole on the bottom of the rod cap that splashes in the crankcase oil is not getting enough lubrication to the rod journals on the crankshaft. The holes will be enlarged slightly and a lip milled into the cap that will help to capture additional oil and force it into the hole. An oil groove around the inside of the rod cap and an additional hole from the top of the rod may also be drilled to bring in more oil. It was also decided to drill eight small holes under the oil ring through the piston walls. Those and a knife edge on the bottom of the piston sleeve will hopefully help remove excess oil from the cylinder wall. (10/24/07)

As of January, 2009, the engine has run over a gallon of gas through the carburetor and is smoking less and running better each time as the rings seat. Tom is happy to fire up the engine for a demo run for any and all visitors to the museum.

February 6, 2009

To eliminate the separate water tank and keep everything mounted to one base, Tom has created a finned aluminum water cooling tank that mounts to the engine base. The on/off switch has been relocated to make room for it.

Here are some close-up photos of the 1/2-20 filler cap being threaded. The Sherline lathe with tread cutting attachment was used to cut the male thread. The 1/2-20 thread in the lid was tapped. A drain hole and plug remain to be installed in the tank bottom.

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New Submissions Welcomed

If you have additional information on a project or builder shown on this site that your would like to contribute, please e-mail mecm@craftsmanshipmuseum.com or mecm@craftsmanshipmuseum.com. We also welcome new contributions. Please see our page at newsubmit.htm for a submission form and guidelines for submitting descriptive copy and photos for a new project.

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