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Have You Always Wanted an Oil Filter?

Announcing the AT-4F Oil Filter System

Diagram of Oil Filter (12k)


  • Separately mounted Filter Assembly for ease of installation and maintenance.
  • Easy one hour, "bolt on" installation, all necessary components included.
  • Uses standard automotive spin-on cartridges.
  • Built in pressure regulating valve for improved regulation.
  • Compact Design--10.5 x 4 x 4 (incl 1.5" for filter removal).

Introducing the AT-4F Oil Filter Sytsem from Indigo Electronics. This kit has been expressly engineered to upgrade the Atomic 4 engine and provide long overdue engine oil filtration.

The nemesis of any internal combustion engine is dirty oil. As built, the Atomic 4 had no provision for any oil filtration whatsoever. Even if the oil is changed each season, combustion byproducts begin to contaminate new oil as soon as the engine is operated. Now you can have the assurance that your engine will stay in top condition with the addition of an oil filtration system. The oil system of the Atomic 4 typically "dumps" back to the sump, via the internal pressure regulating valve, about 40% of the oil pumped. The Indigo System takes oil from the engine via the existing connection on the block where the oil pressure sending unit is attached, regulates the oil pressure and diverts the excess oil through an external filter and then returns it to the sump via the existing 3/4 NPT connection in the oil pan. While not a true "full flow" filtration system, the external filter does clean all of the oil in the engine about every 4 minutes at the cruise speed...a tremendous improvement over no filtration. Start cleaning up your engine today with the only kit expressly designed for the Atomic 4.

A Complete Retrofit Package

Easy one hour installation includes:

NOTE: A Sump Oil Removal Tube and Pump-Out Connecton are no longer included with this Kit

Optional Oil Cooler Now Available

As designed and built the Atomic 4 has no provision for cooling or warming the oil. As a result, it takes about an hour of operation for the oil to get up to a reasonable operating temperature and continued operation beyond about an hour causes the oil temperature to continue to rise until it gets quite hot and thin. Depending on the condition of the bearings and oil pump in the engine, this is quite often seen as a significant drop in oil pressure. The Indigo Oil Cooler is designed to help control oil temperature and thus maintain oil pressure after periods of extended operation. The cooler is installed in conjunction with the Indigo Oil Filter system, between the engine and the oil supply to the filter, and utilizes warm engine cooling water to both warm the oil just after startup and then cool the oil once oil temperature warms to the point that it exceeds the temperature of the cooling water (see Diagrams). Cooler dimensions are 11" long by 2" diameter, excluding any hose fittings.

Diagram of Oil Cooler installed in a Raw Water cooled engine

Diagram of Oil Cooler installed in a Fresh Water cooled engine

Price $135

(includes 3/8" hose barb fittings on oil and 1/2" hose barb fittings on water)


As advertised in Good Old Boat

Call today for Credit Card orders or send check/money order to:

Indigo Electronics, Inc.

105 Pipe Kiln Court
Williamsburg, VA 23185

Order Today. You never knew sailing could be so much fun!
1-800-428-8569 toll free
or 757-593-8569



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