Page updated on: January 31, 2008

Converting the Mazda 13B Automobile Engine for Use in an Aircraft

Overview

This web page will detail the designing, building and testing the conversion of a Mazda 13B automotive engine for aircraft use. It is hoped enough information will be provided to allow others to learn and to duplicate our conversion.

Building the test frame

One of the goals of this project was to have a reliable engine. To do this we felt it was necessary to debug the engine systems before installation. This means running it on the ground until we are confident it will be reliable in the air. We also wanted to run it in an environment as close to the actual installation as possible and transfer most of these tested components directly to the plane. So, a frame was built to run the engine on the ground.

The frame has a full scale firewall mounted to it and the actual engine mount which will be used on the aircraft. The frame has also been designed to be mounted on a trailer so it can be towed to an area suitable for running the engine. We would like to remain welcome in the neighborhood.

Adjusting the torch.	Welding the frame

More welding	Smile!

The completed frame	Close-up of the completed frame

Engine mount attached to the front of the frame	Testing the weight capability of the frame and engine mount. Yep, it's strong!

Verifying the center of thrust is where we think it should be.

The Engine

The engine is a 1989, Mazda 13B Turbo II. It was purchased from a mechanic who had planned on installing it in his car. After having the engine for awhile, life became to busy for him to complete the project. So, in August 2005, he sold it to me for $1,300.

Checking the exhaust manifold for interference with the intake manifold.	Note the custom made fuel/air intake pipes. They are considerably lighter and much smaller than the stock intake.

The green box at the top of the engine is a mock-up of the fuel/air plenum.	This is all of the stock components removed from the engine. They are no longer needed.

We put all of the removed stock components on a scale. The weight was 40 pounds!

Fuel injection and ignition controller

The MegaSquirt will be used as an engine controller for performing the initial testing of the engine. For the final testing and installation in the plane, we'll be using Real World Solutions, Inc rotary EC2 EFI & Ignition Controller.

The MegaSquirt on the bench ready for testing. The white vacuum pump in the lower half of the picture is used to simulate the intake manifold vacuum created by a running engine.

Fuel System

The Cozy fuel system was designed around a carbureted engine. Our engine is fuel injected so a few modifications were needed.

The fuel system for a carbureted engine, is very simple. The fuel flows from the tank to the engine. There is no return feed. In a fuel injected engine, the fuel flows from the fuel tank to engine. Then the fuel which is not used is returned to the fuel tank.

There are many methods to return the fuel. Most require the pilot to keep track of the tank being used and where the fuel is being returned. To simplify the pilots workload, we are returning the fuel to the same tank from which it came. This is done using a fuel valve which can handle both the fuel to the engine and fuel being returned.

A fuel injected engine also requires a higher fuel pressure. In our design, we have two high-pressure fuel pumps. Only one will be needed. The second one is a backup.

Schematic of the fuel system.