Power Cube Review
Contents
Power Cube 15.6
This review is from the experiences in building Power Cubes in the July workshop held at OSE Factor e Farm in Missouri. Six of the Power Cubes were provisioned for the workshop.
While the workshop went well and functional Power Cubes were built, some unexpected issues arose during the build that are addressed in this review.
Each of the issues are discussed below, along with resolutions and updates to enhance the 15.6 builds.
Control Bracket
The bracket supporting the throttle and keyswitch had already been re-designed to address some prior issues. The steel had already been cut for the workshop, so we rotated the bracket 90 degrees CCW and used only one bolt to secure it to the frame.
The issues were mostly about simplifying the design and also to resolve a collision in the keyswitch wiring and the frame. The prior design used a length of 1/8" x 1" x 1" angle iron and a small piece of 1/8" steel, both welded to the control bracket. The updated bracket didn't need these and used an updated CNC cut bracket as shown below.
Another issue arose when the keyswitch did not fit in the hole provided. This was thought to be due to the tapered hole resulting from the CNC torch. It was resolved with some grinding with a Dremel. In the future, this should be resolved with better CNC control. In many cases, these issues can be resolved with oversizing holes, but this keyswitch hole relies on a flat in one side of the hole to prevent the switch from rotating. Oversizing the hole may allow the switch rotate in the hole.
A third issue arose with the throttle control not fitting in the slot provided. The cable required that the slot be elongated - this has been addressed in the updated bracket above.
Pressure Plumbing
The holes in the Pressure Plumbing bracket did not match those in the pressure relief valve. The holes in the Sketchup pressure relief valve was 1/4" wider than the real item, as described in the Prince Documentation:
The holes have been moved in the Sketchup model to match the valve.
Return Plumbing
The Return Plumbing did not fit in reality as it did in the Sketchup model. A 45 degree elbow was missing from the BOM and was not ordered for the build. A similar elbow was secured just before the workshop, but it required an additional nipple, extending the hose an extra 1.5" - 2" and if mounted to the bracket as intended, it would intersect the engine oil cooler (not in the Sketchup engine model). For the workshop, we unbolted the oil filter from the bracket and let it hang freely.
The resolution would be to use the proper 45 degree elbow and to possibly alter the bracket to be a "T" rather than an "L" and move the oil filter forward by 2" - 3". The resolution will have to be determined by analyzing the physical geometries of the engine and plumbing with a ruler, as the model in Sketchup is not accurate enough.
Suction Strainer Port
We have been using a common plumbing union to weld an extended flange for the suction strainer port, but they have been problematic for welding.
This time, we found that they are made of cast iron and that we should instead use something of steel more suited for welding. To resolve this, one solution would be to use a weldable flange and a bushing to add distance for the suction strainer.
Surplus Center parts:
Wiring Harness
The wiring harness is shown below in schematic only.
