Radiator Bracket Installation...
...right / left radiator brackets
...10mm wrench
...12mm wrench
...3/8x3/4x36" Hi density automotive grade foam tape
Installing the Lower Radiator Bracket...
The 1st gen RX-7's front chassis brackets changed slightly over the years. Early cars used a radiator/oil cooler assembly, where later cars used seperate oil cooler mounting tabs located down in the chassis just in back of the front sway bar. Depending on which style your car uses, installation is as follows...
'79-'80 SA Chassis...has rectangular sheetmetal "tabs" extending inward from the frame rails, located just in back of the front sway bar. Our lower rad bracket slides over these tabs. Some cars require slight trimming of the chassis tabs for a good fit.
'81-'85 FB Chassis...has oil cooler brackets extending upward from the chassis, with each bracket having a horizontal flat pad on top that has (2) holes. Our lower rad bracket for this chassis simply lowers onto/attaches to these pads, placing the lower part of the radiator mid-way between the RX-7's round front crossmember and it's front swaybar.
Radiator Installation...
...Radiator
...radiator aluminum upper seal panel
...10mm wrench
...RTV Silicone Sealer
...Apply (2) 1/4" beads of silicone sealer to each of the locating pads on the lower rad bracket. This step prevents excessive movement and wear to the rad's contact points.
...Slip the radiator into the installed lower radiator bracket. The radiator's lower channel will fit snugly over the lower bracket's locating pads. A slight amount of silicone should squeeze out.
...Place the upper aluminum radiator seal in position at the top/front of the radiator. It will fit over the radiator core's upper channel, and bolt to existing holes in the RX-7's core support.
...secure the optional side seal panels using existing holes along the sides of the core support. These panels can also be used to locate you AC system's condensor core. Just use a drill to make the necessary holes and fasten the cond core w/ sheetmetal screws, same method as that used by Mazda.
Radiator Hose Installation...
...upper hose
...lower hose
...(4) hose clamps
...Trim the hoses to length (if necessary) & install. Make sure that the lower hose has a spring type insert inside to prevent hose collapse at high RPMs.
OPTIONAL RADIATOR NOTE:...If you want to use your stock RX-7 radiator, it will need to be re-located farther forward to a more vertical position. Some people have had success with the stock radiator by fabricating simple "L" shaped angle iron brackets for each side. Others have used radiators from different applications, using similar fabricated brackets. Even stock LT-1 Camaro radiators have been installed by denting in the sheetmetal “frame-rail” sections of the RX-7 to make some additional room. Whatever solution you decide on, if you live in one of the warmer climates such as Arizona or Florida, you will need to pay extra attention to directing every last bit of air drawn in by the fan THROUGH the radiator, instead of around it. This means sealing off all the paths above, below, and around the rad with sheetmetal, cardboard, or foam. REMEMBER...the RX-7 has a small engine compartment with minimal exit paths for the hot air to escape from. If the air can’t get out fast enough from the rear and bottom of the engine compartment, it will simply go around the rad or fan to the low pressure area in front, reducing the amount of fresh cool air drawn in. Our radiator kits use the largest possible radiator without requiring major modifications, and our radiator brackets are engineered to seal off the paths around the rad without further fabrication.
Thermostat...Be sure to use a new high quality thermostat that features a balanced design, such as the Robertshaw "extra performance" series. One almost necessary modification to your new thermostat is that a 1/8” diameter hole should be drilled thru the flat area of the disc to allow more thorough purging of any air bubbles when adding coolant. This mod also makes the process much faster, as the bubbles can now travel thru the closed thermostat into the upper radiator hose.
Most 1st gen RX-7s were equipped with carbureted 12a engines, but the '84-'85 GSL-SE used the injected 13B engine. There were differences in delivery pressure and internal tank baffling.
The '79-'80 "SA" tanks held 14-1/2 gallons, used fittings welded to the top of the tanks, and had a larger depression for a larger "full-size" spare tire well.
The '81-'85 "FB" tanks held 16.4 gallons, used fittings that went thru the fill plate, and had a 2" less depression for the FB's "space saver" sized spare tire well. All FB tanks are identical, but the fill plate/pickup tube assemblies differ between 12a and 13b applications. 12a's got 5/16" suction tubes and no baffle cup, while the 13b tanks got 3/8" suction lines and a EFI style baffle cup on the suction end of it's larger pick-up tube.
Cars equipped w/ 12a tanks/pumps...While perfectly fine for a daily driver carbureted V8, the original fuel pumps and gas tank baffling used with the carbureted cars are not adaquate for an injected system.
Cars equipped w/ 13b tanks/pumps...If you are using a carburetor with your conversion, a fuel supply loop should be plumbed in to make the hi-pressure EFI fuel pump compatible with the low pressure / volume requirements of your carburetor. The RX-7 fuel pump must have a constantly circulating fuel flow through it for cooling purposes. To make both the carburetor and fuel pump happy, we install a “T” into the fuel line, connecting the pressure and return lines together, to form a path for the fuel to circulate back to the fuel tank. The 3rd leg of the “T” should go to a fuel pressure regulator (available at any auto parts store), then on to the carburetor. Plumbed like this, fuel will just return to the tank through the return line without building any pressure for the carburetor. In order to get the 4-6 psi pressure recommended for the carburetor, some restriction is
needed in the return line. An easy way to get this restriction is to use a pair of “Vice Grip” type pliers, and slowly and incrementally crimp the steel section of the return line until there is about 8-10 psi before the pressure regulator. After this is achieved, the regulator can be adjusted to further drop that pressure to 4-6 psi for the carburetor.
Injected applications...Most 1st gen RX-7s were equipped with carbureted 12a engines, but the '84-'85 GSL-SE used the injected 13B engine. The original fuel pumps and gas tanks used with the carbureted cars are not adaquate for an injected system. The stock GSL-SE fuel pump is compatible in both pressure and volume for the injected 5.0 V-8 engines (injected RX-7’s typically run about 45 psi of fuel pressure at the injector). Since the pressure regulator is located on the end of the engine's fuel rail, fuel pressure is automatically adjusted to the requirements of the engine.
Re-plumbing the RX-7's AC system is easier than one might think. We suggest that you re-use the OEM hose fittings/pipes from the RX-7 at the firewall, condensor, and drier. Re-use the OEM hose fittings for the compressor that you are using. Salvaging these fittings will not only save you money, but it will insure that you have the correct fittings for your application. The salvaged fittings will be fitted with new hose and crimp sleeves, and hose length and fitting angle can be adjusted to your exact requirements. The AC system plumbing should be routed as follows...
...large firewall fitting connects to the compressor suction port.
...small firewall fitting connects to the reciever/drier outlet port.
...compressor pressure port connects to top of the condensor core.
...condensor core bottom connects to the reciever/drier inlet port.
After the hose lengths and fitting direction are tailored to your application, return to the hose shop to have your new crimp sleeves crimped onto your new hoses permanantly.
After the hoses are attached, you can take your car to the AC shop to evacuate and charge the system.
If your completed AC system is operating under severe conditions, a small 10" fan can be attached to the condensor core to boost performance.
The electrical part of your engine conversion for the AC system is covered in the electrical section.
2....Considerations & Requirements....
4....Engine / Transmission Installation....
5....Exhaust / Throttle Cable / Accessory Drive / Pulleys....
6....Cooling / Fuel Systems....
7....RX-7 Wiring Harness Connector ID and Circuit Locations....
8....Electrical System Modifications By Circuit....