Even though I have the largest radiator and fan I could fit, I was still concerned about the Hemi overheating, so I decided to add an oil cooler. The cooler will be remote mounted, so it requires its own fan, and in order to send only hot oil to the cooler, an oil thermostat was also needed. The fan is from Derale, and the thermostat is from Mocal. When the engine oil is cold, the thermostat will route the oil directly back to the engine bypassing the cooler. Once the temperature reaches 180 degrees, the thermostat opens and directs flow through the cooler and then back to the engine.
The only place with enough space to mount the cooler was behind the rear end on the frame. The cooler location was mocked-up in the frame with some wood blocks and the oil supply and return lines were located. There needs to be some space between the cooler fins and the bottom of the body above for air to be drawn in from the top and through the fins. The cooler also needed to be offset to make room for the oil line fittings. The blue fitting contains the thermostatic switch to turn the cooler fan on and off, so the fan will only be on when the oil thermostat is open and sending hot oil to the cooler.
The weight of the tank will not be taken by the tabs alone. I didnít want the tabs to flex at all with the weight of the fuel, so supports were made for each corner of the tank to take the weight. Triangular wooden pads were temporarily taped to the bottom of the tank and thick epoxy was applied to the trunk floor where the pads were going to sit. The tank was put into place using shims for the correct spacing off of the floor, and the epoxy was allowed to set. This way, the tank was bedded correctly on the wooden pads. After the epoxy set, the tank was removed leaving the wood pads epoxied to the floor. Rubber sheet was added to each pad to complete the tank supports. The fuel tank is now bolted to the frame and rests on the pads for support.
The rear mounts will have bolts through the floor and into tabs welded to the frame. The tank was centered side-to-side and leveled with shims before holes through floor were drilled. Quarter inch tabs were drilled and tapped for the through bolts and welded to the frame. Tabs are just tacked for now and will be finish welded later. The rubber grommets insulate the tank from the frame, so a separate ground strap will be used.
Instead of hold-down straps running across the top of the tank, I specified mounting tabs at each corner. A hole was drilled in each tab and a rubber grommet was installed. Two small threaded stands were fabricated for the front mounting bolts. The stands will be welded to the roll bar brackets which in turn are bolted directly to the frame. The stands keep the tank high enough off of the floor in order to add sound deadener, insulation, and trim.
The Willys fuel tank will be mounted in the trunk between the wheel tubs. I started out by making a cardboard mock-up of the tank, making sure that it would clear the closed trunk lid. I furnished the tank fabricator with dimensional drawings for the tank. It was fabricated from stainless steel, with the fuel pump and pre-filter are mounted in the tank to save space. The capacity was calculated out at 19 gallons, not including the volume taken up by the pump and filter. With a little free board at the top of the tank, it should have just less than 18 gallons full.