The Care and Feeding of the Universal Atomic Four Engine

Possibly updated information and reader editable information

Most Alberg 30s, like most boats of the time, were delivered with Universal Atomic 4 gasoline-powered auxiliary engines. Some people have replace these with diesels, maybe because their Atomic 4 was wearing out or they were concerned about the explosion hazard of gasoline, but the Atomic 4 remains a reliable, safe, cost-effective power plant for moderate-sized auxiliary sailboats. If you make an unfailing habit of running the bilge blower for five minutes and then sniffing the outlet for fumes, you can neutralize the danger.

Still, these engines are getting older. I've been told that this block was the original engine in the Jeep. (I've also heard that they're based on an industrial stationary engine, the International Harvester Farmall Cub engine, and a Chevy.) They're not made any more and, like all of us, require a little tender loving care to keep them happy. Keep it painted to prevent rust. When we bought our boat, this precaution had not been taken. In my ignorance of marine engines, I left it that way. The cylinder head rusted through.

Switching to fresh water cooling can add years of life to your engine. Two of the endemic problems are corrosion and overheating. Both of these are caused by salt water cooling. You can imagine the damage that hot salt water can do over time to a metal casting. The salt also precipitates out in the cooling jacket, blocking the flow of water and causing the engine temperature to rise. As the engine gets hotter, the salt precipitates faster. That's the reason that salt-water engines should use a 140F thermostat. This is a bit cooler than a gasoline internal-combustion engine likes, but it will tolerate it. If you switch to fresh-water cooling, you can install a 170F and enjoy better combustion.

General Specifications

Model Designation UJ, UJR
Engine Type Four Cylinder, Vertical, 4 Cycle, L-Head
Bore and Stroke 2 9/16" x 3 1/8"
Total Piston Displacement 64.46
Compression Ratio 6.3:1
Engine Rotation Counter-Clockwise (From Flywheel end)
Firing Order No. 1 on Flywheel End 1-2-4-3
Reduction Gear Ratio 2.04:1
Maximum Operating Angle Approximately 15 degrees
Fuel Regular Grade Gasoline
Lubrication Oil SAE 30

@ RPM 600 1000 1500 2000 2500 3000 3500
Brake Horsepower: 5 7.3 11.9 16.2 20 25 30

Suggested Oil LevelsAngle of Install'nAmount FullAmount Low
(Quarts) 0 degrees 5.75 5
5 degrees 4.75 4
10 degrees 3.5 2.75
14 degrees 2.75 2.25

Offshore Sailing book cover Offshore Sailing by Bill Seifert with Daniel Spurr

We went to a Windjammers lecture to hear Bill Seifert and I was impressed enough to buy the book on the spot. I've heard a lot of people talk about ways to improve a boat, but I've never heard one person suggest so many good ideas that I hadn't considered. Part of the charm is the specificity of the suggestions. Everyone says you should secure your floorboards, hatchboards and batteries. Bill shows good suggestions on how to do so.

The suggestions are very practical for the do-it-yourselfer, too. Many show how to make or adapt inexpensive solutions. Tip #12 on closing the deck blower vents is one that will pay off for me without ever going offshore. I'll implement that one to stop the wintertime storms from finding their way belowdecks.

Besides modifications, the book also includes advice for operating offshore, cooking, boat selection, dealing with bureaucracy, and more.

Bill Seifert has worked at Tartan, TPI, and Alden Yachts. He's a veteran of many Marion-Bermuda races and now runs his own yacht management company. His tips are born of experience--not of book-learning--and it shows. He obviously knows his stuff.


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