1975 Ericson 27 - There's An Atomic 4 in your Garage

I like motors. They're just plain fun. Can a motor be cute? Somehow, this one is. It is actually a neat little power plant despite its simplicity, which is part of its beauty. It was designed by the Universal Motor Company and was always a marine engine, no matter what you hear otherwise. The Atomic 4 was introduced in 1947, but has long roots that can be traced back to the 1920s, and perhaps even earlier. For a nice history of the Universal Motor Company and information on these motors, see here. It is highlighted by a full cast iron block and pan and transmission assembly. To make the motor very compact, it only has two main bearings. To help recover stiffness, the pan is a very heavy casting comparable to the block. The transmission is actually part of the whole block as well. The result is that it is a solid, "stiff" motor when all bolted together. It is also made of a special corrosion resistant iron alloy. However, converting one of these to freshwater cooling is a great thing to do to prolong life and improve efficiency. You can run a fresh water cooled engine warmer, at a range it prefers, usually around 175 degrees F. Due to problems with precipitants in heating seawater, raw water engines are usually operated at a less efficient temperature in the 130-135 degree F. range.

These photos show the engine in a running state in my garage. It's a little hectic, but what you see here is a prototyping of my own freshwater conversion. I dug around a couple of local salvage and second hand marine shops and came up with almost all my missing equipment. I found what I believe is an Universal M20 heat exchanger in a seemingly unused state (the blue/silver tube), a never used Vetus stainless steel water lift muffler (visible top left in one of the photos), a like new Perko fuel/ water separator. The new items required were a Groco fresh water strainer and a Oberdorfer M201 water pump for the seawater side. I decided to mount the pump so it is being driven off the existing alternator belt (longer belt installed, of course), and could be mounted on existing bolts. I welded the bracket out of scrap angle and steel peices I had lying around the garage. For the purposes of "bench" testing, I've routed the raw side of the cooling to a 55 gallon trash can full of water. On the closed side, I am using an expansion tank off an Alfa 2 litre engine (just happened to have it lying around, worked so well, used it for the final installation). For testing, fuel is being supplied by an outboard fuel tank through the Perko separator. Battery was compliments of prior owner.

Tied into the conversion and general maintenance, I flushed the cooling jacket of the engine with a muriatic acid solution. Take a 5 gallon bucket, and mix up a solution of about a gallon of acid to 4 gallons of water (always add acid to water). Remove the thermostat, pinch off the coolant bypass hose, and run the engine long enough to suck up the 5 gallons of solution and shut it down. Let it sit about 20 minutes and then give the motor a thorough flushing and then run to operating temperature with everything in normal operating mode.

Corrosion is a constant battle in a marine environment, and everything is at risk. With this in mind, I completely repainted this motor and all of its accessories, except the alternator and heat exchanger (can't explain why, just didn't). I took most every thing down to bare metal and repainted with appropriate engine paint or hammer type finishes depending on what I was doing. Basically, if it was part of the block, it got the engine paint, otherwise I did a gold or black hammer finish. This should be durable and certainly looks good for the moment.

While the motor was out of the boat, I also did a valve adjustment and basic tune up.

Finally, we have a few silly photos of it in the trunk of my daily beater, a trusty '86 Audi 4000 Quattro sedan. I think someone on the Audi trunk engineering team is into Atomic 4s. The trunk lid opens almost vertical, so the engine can be dropped straight in by a come-along, with the car backed underneath. Once in, the engine fits perfectly between two side frame members and the alternator just tucks under the deck. All in all, it fits so well you can't believe it. It was also fun to pull up at the marina and say I was ready to have them drop the A4 into Avanti (using the Travel Lift), and they looked out and asked where the engine was, not believing it could be in my little car.