1943 300hp Atlas Imperial

By Staff
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courtesy of Gas Engine Magazine Staff
The Vista, Calif., Antique Gas & Steam Engine Museum’s 1943 300hp Atlas Imperial.

1943 300hp Atlas Imperial

Manufacturer: Atlas Imperial Diesel Engine Co., Oakland, CA
Year: 1943
Serial No.: N/A
Horsepower: 300hp @ 300 rpm
Engine: 6-cylinder, 0,348ci displacement
Bore and Stroke: 11-1/2in x 15in
Ignition: Diesel Compression Ignition
Governing: Volume
Cooling: Water
Weight: 33,100lb

Engine inside of the ship it was taken from.

We have a very nice Atlas Imperial engine at the Antique Gas & Steam Engine Museum in Vista, California. It is a 6-cylinder engine with an 11-1/2-inch bore and a 15-inch stroke. It weighs 33,100 pounds, has a displacement of 9,348 cubic inches and generates 300hp at 300rpm. Some pretty big numbers, but the most important thing is that it is a good spectator engine as all of the valve mechanism is fully exposed. That, and all of the air-start valving make it one of our best attractions. This is the story of how we got it.

The Beginning

Looking back, it was such a big job that I doubt we would have started had we known what we were up against in advance. It required a complete overhaul of our compressed air system, 20 yards of concrete and about 1,000 feet of rebar. It was a huge job that took three years and got perhaps 40 people involved at one time or another.

Looking down on the Atlas’ red valve gear.

In 2011, member Ross Brock attended one of our board meetings and mentioned that there was an interesting engine that we might get. Our museum director told me it might be worth looking into. I got ahold of Ross, who I did not know at the time, and he made arrangements for a visit to see this engine. It was in a boat, and I thought poking around in a boat would be fun even if the engine was a dud. My wife, Diane, and I got a ride out to the boat and took a look at things. The engine was in the Rival, a boat that was purchased at a surplus auction from the Navy by Everingham Bros. in 1974. It was originally the YG-29 and was converted into a small purse seiner and used to catch live bait.

A long view of the Atlas as installed in the Rival, prior to removal.

We caught up with the boat as they were finishing up unloading a series of barge-like holding tanks for the bait fish. We took a ride over to their mooring, which was about a mile away where the fishing boats tie up. Ross and I went down into the engine room to see the engine. It was a large engine sitting in the middle of a very cluttered and dirty engine room. The conversion to a fishing boat needed some auxiliary power and this was provided by two new John Deere diesels, one driving a hydraulic pump and the other a generator. Both were running at 1,800rpm and the noise was shattering, as they had not wasted any money on mufflers. The engine was a winner though, with completely open valve gear and all kinds of things that moved when the engine was reversed. There was no transmission; the propeller was direct-drive and the engine was direct-reversing. I decided on the spot that this would be a grand addition to our collection.

Reviving the Rival

The Rival, originally the YG-29, was built by the Dekom Shipbuilding Co. in Brooklyn, New York, and launched on July 23, 1943. It worked in a few different places and was then assigned to the 11th Naval District in San Diego.

The early stages of disassembling the 6-cylinder Atlas for removal from the Rival.

YG stands for yard, garbage.  The mission of the boat was to go around the fleet picking up the garbage and then taking it out to sea and dumping it. In spite of a not very glamorous start, it became the backbone of Everingham Bros.’ fleet. They fish mostly in shallow coastal waters and come under all of the smog rules. The Atlas Imperial would not pass and they were forced to re-engine the boat. The smog people had a program of paying for a new engine if the owner of the boat paid for the installation. Part of the deal is that the original engine must be destroyed. After a lot of correspondence, we got the engine as a museum piece, except that at the time it was still in the boat and in daily use.

Man wearing a red cap. white t-shirt, grey jeans and blue gloves.

It was decided by the boat owners that the engine would be taken out of the side of the boat. This was done so that the hydraulic lines would not have to be cut, removed and then put back. The hole that could be made was not nearly as tall as the engine, and this is where we came in. A crew of us went down to the boat and started taking things apart. There was a 1,500-pound chain hoist on a rail over the engine, which helped us a lot in moving things. First we removed both manifolds, then the pistons, and finally the cylinders, plus a huge amount of odds and ends, including about 20 gallons of nuts, bolts, washers, push-rods and a very nice Quincy air compressor. It sounds pretty easy, but it was all way too heavy to move by hand and the workspace was very cramped. To add to the fun, the whole place was covered with a film of oil and fish scales. You did not have to be in there very long before you were black up to the elbows. When we took out the no. 2 piston we were astounded to discover that one connecting rod bolt was loose and all of the adjusting shims had fallen into the pan. The engine had been running in daily service this way, but there was no damage to the rod journal or the bearing.

Yellow fork lift is pulling the engine out of the ship.

We hauled all of this stuff back to the museum and started putting it back together. The first thing to do was build a foundation. This took an excavation 5 feet deep with 2 feet of compacted gravel on the bottom and then 20 yards of concrete. The next step, which took about 3-1/2 years of weekends, was to clean and paint everything as it went back together. As this all evolved we discovered a treasure trove of junk in the bottom of the pan. This included a flashlight, several wrenches, some rags and welding rod stubs. We also discovered that the safety wire was missing from the no. 2 main bearing cap. This immediately aroused our suspicion, so we removed the cap and found that the bearing was ruined. We guess that it was probably too tight, although it could also have been from oil starvation. One of our members who worked in San Diego stopped by the boat, which was back in service, and pawed through a small, cramped storage space in the very stern of the boat and was lucky enough to find a brand new bearing in the original box! Surprisingly there was no damage to the crankshaft. The rest of the re-assembly was pretty straightforward.

Fork lift is lowering the engine onto cement blocks. With 3 men guiding it as…


The thing that was not straightforward was setting the timing. This is done by turning the crankshaft a little ways, lining it up with one of the stamped numbers on the flywheel, and then setting the appropriate valve. There are three valves per cylinder; exhaust, intake, and air start. The injectors are also operated by the camshaft, and each has its own rocker arm. This is a pretty big job, and when it finally appeared to be complete we decided to give starting the engine a try. We did this while another event was going on and had a lot of spectators for our first start-up, so naturally, everything went wrong.

he crankcase bolted down with its upper crankcase installed.
One of the Atlas’ cylinders and a homemade cylinder hone.

The first thing that happened was that one of the valves was adjusted wrong, and this caused an over-pressure situation that in turn made one of the safety relief valves open. It sounds like a rifle shot when it opens and gave us a pretty good scare. During the very long time the engine was going back together we had never missed a chance to make sure the cylinder bore was kept well oiled. This paved the way for our next problem. We managed to get the engine to run: not very well, but it did run. We were pretty happy about this and were busy patting each other on the back, but unknown to us was that all of the extra oil we’d lavished on the engine went up the stack, traveled about 100 feet and then descended on a visitor’s car. The owner was furious with us. We managed to send him off to the office where he yelled at everybody. Our director calmed him down and then came out to see what we were doing. His only comment was that the car would never rust.

A volunteer preps the gaskets for the cylinders.
Restored green engine with red and blue pipes
Black and white photo of old navy ship.

We spent the next several weekends getting the valves set right. Since this engine runs in both directions it makes valve adjustment amazingly touchy. The method is to set up everything in the direction used most and then see how it runs in the other direction, and then find a good spot in between. This is just plain labor, and we completely wore out several people doing the crankshaft turning. It is a big engine and it does not turn easily. Getting this right, plus all of the oil, fuel and cooling plumbing was really a huge job.

We have this engine displayed a little differently than the others.  We have a very limited safety fence and encourage visitors to walk freely around the engine, to feel it and really get up close and personal. The Atlas Imperial has been a big success for us. The time spent getting it put back together and running has been a worthwhile investment.

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