The Seal Engine Project—Full Build

Below we have documented the Joe Martin Foundation Seal engine build from start to finish. Photos and descriptions of the components illustrate the unique collective craftsmanship—with a beautiful final result.

Seal Engine Project Starts (7/25/06)

Seal Engine Progress—October, 2006

As of October 4, 2006 the block and manifolds were coming along nicely in the museum shop. Pam Weiss was at work on the camshaft and timing gear, and Joe Martin was testing a program to grind the cam lobes on a Sherline CNC milling machine.

A note from the build team: we modified the cam drawing to match the firing order published in the plans. It turns out that the drawing was correct, and the listed firing order was wrong. An old article in Model Engineer magazine, by engine designer Edgar Westbury, explained the error—but we learned of it too late. As a result, our firing order is actually different than what Edgar originally intended, but it runs fine.

Seal Engine Progress—November/December, 2006

Seal Engine Progress—January/February, 2007

First Test Run-In —(3/28/07)

On March 28, 2007 we did our first run-in of the Seal engine, with the short block being run using a Sherline lathe as the drive. Tom filled the crankcase with mineral oil, and we took a video of the motor being run at low rpm. By running it for a short period we were able to break in the wear surfaces, and make sure that everything ran freely. As you can see in a second video, it spins fine!

Seal Engine Progress—April/May, 2007

Seal Engine Progress—June/July, 2007

First Pop!—July 21, 2007

Close, but No Cigar

We had Champagne chilled and waiting, but never got to open it. There was still more work to be done before we had a smooth running engine. Anyone who has tried building an internal combustion engine from scratch will probably not be surprised by this. However, a word of congratulations should go out to all those who participated in this project. No parts failed, and they all fit together well. From this point on it was just fine tuning. Watch video of the first, second, and third pop.

Seal Engine Full Run—August 8, 2007

Finally, the Seal engine is a success! Within a week or so of the first pop, Joe and Tom got the kinks worked out. They had to clean and re-gap the spark plugs, raise the gas tank, and make a few other minor adjustments. The final result is a strong running Seal engine. Tom fired up the engine for this video of the full run. It now starts with a twist of the flywheel, idles at less than 1,000 rpm, and revs freely. The Seal engine does pass a little oil, but this is normal because there are two compression rings on the pistons, but no oil rings.

Joe and Tom would continue to refine the fuel system to improve performance throughout the rev range. Craig also built a more appropriate base for display in the museum, and designed a plaque to honor all those who contributed parts.

What next? After finishing the Seal engine build, we were ready to move on to the next museum shop project. Once again, this project would be a group build. Ultimately, we chose to build and document a Howell V-4 IC engine as the second Craftsmanship Museum shop project.

Post-Completion Engine Updates

Tom demonstrating the Seal engine for a hotrod club.

Tom demonstrating the Seal engine for a hotrod club from Fallbrook, CA in December, 2008.

After many demonstrations, the engine now has several hours of running time on it—mostly in 1-3 minute runs. In mid-November, 2007 the engine seized while Tom was test running it. The rod on the #1 cylinder galled the crankshaft, causing the engine to stop. Fortunately, no other damage was done. 

Tom disassembled the engine, cleaned and polished the crankshaft journals, and did the same for the rod bearing surfaces. The galling was insignificant enough that it could be polished out. It was determined that the small hole on the bottom of the rod cap, which splashes in the crankcase oil, was not getting enough lubrication to the rod journals on the crankshaft. The holes would be enlarged slightly, and a lip was milled into the cap. That would help to capture additional oil and force it into the hole. 

We also considered making an oil groove around the inside of the rod cap, and drilling an additional hole from the top of the rod to bring in more oil. Along with that, we decided to drill eight small holes under the oil ring through the piston walls. Those holes, and a knife edge on the bottom of the piston sleeve, would hopefully help remove excess oil from the cylinder wall. (10/24/07)

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

Seal Engine Update—February 6, 2009

We thank all of the craftsmen involved in the Seal engine build for contributing to this rewarding project. It was truly a group effort, and the build team should be proud of this fine running Seal engine. To learn about our second museum shop project, visit our page for the Howell V-4 build

Presented by The Joe Martin Foundation for Exceptional Craftsmanship