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Lynn Jarvis's Sonex project (10)

  

The engine

February 2003 and on to the business end - the firewall forward. Apart from a basic installation guide, the plans end here and the learning curve takes a steep climb. The Bingelis books were a good reference, as well as whatever I could glean from the internet and email group support. But I found that in the end you have to make decisions of your own and get on with it.

I bought the 4 cylinder Jabiru 2200 engine back in 2000 so I had some concern with corrosion during storage. I wanted to get the heads machined to the latest specs anyway, so off they came. Sure enough the exposed cylinders were corroded, not badly enough to require replacement but enough to require resurfacing. In any case, I had to install new heavy-duty wrist pin circlips, so off came the cylinders as well. In fact I am glad of this because I have much more confidence in the engine as a result. My experience with VW engines really paid off. Simple things like counting nuts, circlips or anything loose before and after assembly, and plugging up any holes to stop flying circlips or tools, or anything else, dropping into the crankcase. Simple but vital I can tell you.

The cylinders

The Jabiru 2200 cylinders after honing and with pistons and rings in place ready for assembly. The rings pressed into the cylinders quite easily due to a bevel on the cylinder skirt.
Engine assembly

Easy as we go. Everything plugged up to stop anything falling into the crankcase. The replacement heavy-duty wrist pin circlips were a beast to install. And I had to work out the order of installation or things were impossible to reach. But with patience I got there.
The engine mount

I had bought the engine mount ready made from Sonex. After much struggling to get it to fit I wished I had made my own. But finally it all fitted OK and it was time to install the engine. You can see the battery box and wiring here but I will go into that later.
Engine installation

In 5 minutes it was done. I had my Dad help and we simply lifted the engine onto the mount. A bit heavy maybe but it was not a struggle. This shot shows connection to the carb etc. See below.
The Aerocarb

Rather than develop an air pressure controlled installation for the standard Bing carburetor, I decided to install a Sonex Aerocarb - a throttle body that includes a mixture control. You can see it here connected via Scat hose to the carb heat control box.
The carb heat box

The Aerocarb is very resistant to icing and can be used without carb heat, but I decided to install it in any case. The box contains a flapper valve that directs air from either the air filter or a heat muff that I fitted around the muffler.
The air filter

The Sonex air filter is made to match the Aerocarb and is designed to fit directly on the carb inlet for the 3300 engine. But this doesn't work on the 2200 due to the engine mount bracing just behind the carb. So I mounted it on the heat box. It will draw air from inside the cowl but with an external air scoop to provide fresh air and cooling for the voltage regulator.
The oil cooler

I found a local source for the recommended B&M oil cooler so I ordered one. But I soon found that there was no guide to installation for the 2200 engine, only the 3300. So I devised an air box for installation of the cooler on the rear of the engine mount. Air inlet is at the side.
Oil cooler air control

Others have found that the oil cooler can work too well, especially in winter, and the oil never reaches operating temperature. So I made a flap and lever to control the air entering the cooler. Not cockpit controlled but at least something for adjustment.

The next page in Lynn Jarvis's Sonex project features Electrical.


Lynn Jarvis's Sonex project

  |   1. Introduction  |   2. Sonex specifications  |   3. Building the Sonex  |  

  |   4. The tail and spar  |   5. The wing  |   6. The aft fuselage  |   7. More on the fuselage  |  

  |   8. It all comes together  |  9. The canopy  |   10. The engine  |   11. Electrical  |   12. The cowling  |  

  |   13. Paint and polish  |  14. Moving  |   15. Finishing  |   16. First flight  |   17. Natfly 2004  |

Copyright © 2004 Lynn Jarvis