Fuel Injection For Your C180

Many of you, if like me, would like to improve the performance of our C180’s. The old girls do a great job as mother Cessna made them especially if they’re lightly loaded and at sea level. Load your Skywagon with floats or if on wheels, full tanks, camping gear, the wife and kids and then operate it out of a mountain lake of strip at 5000 feet or so and you’ll wish for more horsepower. The offering of higher horsepower, from form-fit-function and literately bolt-in engines available from Continental is hard to ignore. At overhaul time when one is looking at $20K or more for a new engine, the attraction to a higher horsepower engine at little or no premium over an overhaul is real attractive. So following along these lines late last year I geared-up to replace the O470-R in my 66 C180 H model with more horsepower. I had purchased a run-out IO520-D off of a 1982 C185 some years back and made the decision to install this engine, as designed by Continental, in my airplane. That would mean fuel-injection in lieu of the original carburetor system. My reason for using the fuel injection rather than carburetion had to do with wanting a stock engine with quantifiable book numbers, even air-fuel distribution and no carburetor icing. This article is not about arguing one induction system over another, but rather about the challenges of the installation of a fuel injected 300 horsepower IO520-D into a C180.

This installation required a considerable amount of time and effort however it is quite straightforward. Although I’m an A&P (newly minted) I’m far from being an expert on this sort of thing. I used the Air Planes (old Bonaire) STC to modify the airframe to accept this engine installation. Other engine STC’s are also available i.e. IO550 etc, and should you wish to use Air Planes services I found them accommodating and easy to work with. The STC walks one through the modification and installation of; fuel, induction, electrical, baffling, controls, instrumentation, weight and balance, placards and POH systems. It can be performed on any C180 regardless of vintage and allows for the selection of three different three-blade propellers. No two-blade props are identified on the STC.

For H model (1965) and newer there is no modification to the firewall, earlier models may require a small cut out to accommodate the oil pump and mechanical fuel pump. The cowling drawings show louvers and exhaust outlet baffling for floatplane operations. Otherwise the standard single outlet exhaust is reusable. It does require the installation of a fuel header tank as well as a mechanical and electrical fuel pumps. They were not particularly difficult to install. These systems are germane to the IO520-D and as such are part of this installation. The header tank fits inside the tunnel in front of the control wheel column and some fuel lines require rerouting. Air Planes will build and bend these fuel lines as part of a care-package of available parts. You can “source” many of the required parts as I did or order them from the STC holder. One parts package that I opted for included electrical switches, electrical fuel pump and a wonderful adapter that allows the mating of the fuel-injection fuel control unit to the C180 air-box. This adapter allows the connection of your existing cowling induction air-boot to the existing air-box. Further more the existing carburetor heat system becomes the new alternate air system.

The electric fuel pump, unlike C185’s, is not mounted on the firewall but rather it is located under the passenger’s floor. I’m told this is where C206 and C210 have located their electric fuel pumps. At any rate this location does not require a cowling air scope for cooling. Apparently firewall mounted fuel pumps, because of their proximity to higher heat, require additional cooling i.e. forced air via the cowling scope.

Firewall penetrations for fuel flow indication, throttle and mixture controls, wiring etc.. is at a minimum. New throttle and mixture controls are required and together are routed through the firewall. These control cables work without the firewall “cut-out” needed on C185’s for control linkage space. This is why my firewall worked without modification.

A lot of cutting, bending (I made all of my fuel lines), drilling etc was needed but I find therapy in this type of thing. I measured the time to accomplish this installation in terms of months my airplane was down. I had the engine ready to install as well as all other parts available and waiting. Working most weekends and an occasional evening or two it took me three months to do this job. Lots of help from other C180/185 aficionados made this time and effort pass quickly.

Next newsletter I’ll review the performance changes. Al Hewitt