Re: Thinking about a Electric fan for the TJ Need Info
I put electric fans in my CJ7. Since I'm always looking for a quality, but do-it-myself project, I choose to make the electric setup for the 258. I picked up a couple of 12" matching Import Vehicle Fans (Honda?). Beside picking up the fan motor and fan blades I also wanted the fans with the 3 or 4 metal brackets supporting the fan motor so I could weld then as needed and not have to fabricate the actual motor supports. I also picked up a flat sheet of steel that would form the base of the shroud for the two new motors and picked up a couple of 2" strips of steel about 3 feet long to form into circles to mount the fan motors into and picked up angle iron to use as supports.
Build a fan and shroud unit that would (a) easily slide in behind the radiator and use existing supports used by factory fan shroud, (b) hold the electric fans at an appropriate distance from the radiator fins, (c) seal all air flow so fans could effectively pull air through the radiator without losing air pressure to holes in the shroud, (d) provide stability from vibration for the 2 electric fans.
(1) Measured and cut the sheet steel so that it would fit in place of existing factory shroud. However, let the edges of the sheet steel long enough so I could create lips on all sides. The top and bottom lips were made long enough to extend to the radiator and to shut off airflow through the top and bottom between the shroud and radiator. The sides as well as the top and bottom were cut and measured so as to provide adequate offset from the radiator for the fan blades.The lips were to provide the distance of the shroud from the radiator.
(2) Circles were cut out of the sheet steel where the fans would be mounted through the sheet metal and aligned on the radiator. The cutting of the circles considered the width of the salvaged fan blades and the thickness of the flat steel that would be placed inside the circles cut into the sheet steel. The size of the circles resulted in about 1/2" spacing between the two circles on the inside and about an inch spacing between the circles and the outside edges of the shroud. 2-5 inches existed between the tops and bottoms of the circles and the top and bottom edges of the shroud.
With the circles cut slightly larger than the fan blades, I took the 2" flat steel and formed it into a circle inside each of the holes cut through the sheet steel. After cutting length to a tight fit and using of a small ballpin hammer the 2"flat steel liner fit snug up against the edges of the outer sheet steel holes. Removing the 2" piece which formed a circle, I spot welded it so it would hold as a circle.
(3) Leaving the metal braces on the salvaged fans, I cut the braces where they connected to the shrouds picked up with the salvaged fans. What I ended up with were then two fans with the center fan support holding the fan motors and the three braces running from the the supports. Then, taking the fan and supports, I laid them on top of the flat steel circles with the fan blades sticking through the circle. Then centering the fans and trimming and cutting the 3 fan braces, I welded them to the top of the "circled" 2" flat steel that had previously been welded into a circle.
(4) Then taking the salvaged fan, blades, and now the flat steel circles, I inserted it through the hole cut in the sheet steel. Once I measuredd and determined the distance I wanted the fan blades to be from radiator I slide the steel ring in to move the fan closer and out to give more distance. Once I decided on the distance, I then ran a bead of weld around the ring and the flat steel shroud.
(5) Bottom of the shroud was trimmed and adjusted for lower radiator hose and top was slightly cut to permit for upper hose. High temp rubber was used to seal edges and to prevent excessive vibration from the fans.
(6) Additional supports - small piece of steel were welded between the two circles to prevent movement of the fans. Angle iron was placed on the top and bottom of the shroud metal to also prevent flex in the flat steel. Sides did not need this as they mounted easily into the side support bams.
(1) Ran one fan off of the ECM so computer controls would be used for this onboard air, idle, etc.
(2) Ran separate circuit for second. Bought thermostat and mounted on second fan. Then wired in the thermostat as an automatic set slightly higher than the ECM controlled thermostat. Also ran a bypass for this fan with an inside cabin switch to permit manual control.