Indigo Electronics Atomic 4 Belt Tensioning Device

Original Design

As originally built, the Atomic 4 engine was not equipped with any means of adjusting belt tension. Brute force or some sort of "jury rig" was used instead. As a result, it was very difficult to obtain the proper belt tension. This problem becomes more of an issue when a Fresh Water Cooling pump is added or a high output alternator is installed.

New and Improved Indigo Design

What is it? - The guiding principle behind the new Indigo design is a simple, convenient, and effective means of adjusting belt tension. A very simple jacking mechanism has been developed to allow for proper belt tensioning in even confined locations. Shown below are views of the device as installed.

The two components that attach to the alternator adjusting arm are 3D printed to allow for a very compact yet robust installation. In order for the assembly to apply the necessary force to adjust the belt tension and then maintain that position in operation, a bronze bushing is installed in each 3D printed component that attaches to the alternator adjusting arm such that the clamping force on the arm is provided by the bushings and not the 3D printed material. This is an important distinction in that 3D printed materials are known to "creep" under heavy loads and/or elevated temperatures. This extra bushing may be overkill under certain conditions but we wanted to insure that components remain properly tightened and in position once installed.

How Does it Work? - The existing bolt that locks the alternator in position relative to the adjusting arm is removed. A new small and a new large sub-assembly are attached to the adjusting arm with a new alternator locking bolt and the bolt attached to the small sub-assembly. By rotating a long "coupling" nut on a stud, the alternator is easily lifted to properly tension the belt. Once the belt is properly tensioned, the new bolt and nut are fully tightened to lock the alternator in place.

NOTE: The long coupling nut is utilized to allow easy rotation with a wrench even if you cannot readily see the nut and must feel your way along.

Easy 30 minute, "bolt on" installation, all necessary components included. Easily adjust belt tension in even the tightest engine compartments. All fasteners Stainless Steel.