Jabiru Liquid Cooled Heads

The Jabiru series of aircraft engines have been popular amongst the sport aviation community. Rotec have assessed the engine and, in our opinion, it is well put together. The main issue is the lack of cylinder cooling and this is where most of the serious issues arise. Very careful operation of the air-cooled Jabiru is required to avoid permanently damaging the cylinder heads and/or engine. The Rotec LCH conversion eliminates any technical issues relating to head temperatures and therefore has greatly enhanced the engine’s ability to go the distance. With water cooling at nearly 30 x that of air, it is clear to see the enormous advantages of the LCH program.

Read the LCH installation manual. Also see the Documentation tab in the Liquid Cooled Heads page, for more LCH documents and information.

Each of the LCH heads are lighter than the stock Jabiru 2200 air-cooled heads by around 250g each. Air-cooled Jabiru 3300 heads are comparable in weight to raw LCH heads. So when the weight of the coolant, piping and radiator is added, the penalty is very small. To date no installation has required any adjustments to weight and balance. When using the Rotec LCH the Jabiru fiberglass air rams are both deleted in almost all installations.

See weight comparison movie here for more information.

The LCH fits all Jabiru engines, 4, 6, and 8 cylinders, with hydraulic or solid lifters. On the later hydraulic engine we blank off and plug where the external rocker oilers would once have been. Other than that there is NO difference between heads.

All stock Jabiru components are transferred to the LCH head. i.e. the Rockers, Valves, push rods, push rod tubes, spark plugs etc. These are all retained and located in exactly the same location.

Please watch the following for more information:

Yes, several aircraft are flying now. Go to our LCH Projects Page to see some of our customers projects.

Terry Ryan (from Tocumwal, NSW, Australia) has 50+ hours on his LCH conversion and loves it! He flies all day at around 1/2 the CHT of an air-cooled Jabiru. His compression on his old engine are now like new! Terry Ryan also has his second jabiru engine converted to Rotec Aerosport Liquid Cooled Heads.

Rotec Aerosport recommend the following:

Pump	Description	Documentation
	Use the 80L/min pump for standard Jabiru 2200 & 3300 installations.
	Use the 15L/min pump only in installations with exceptional radiator performance and the with the fiber glass ducts are retained.
	Use the 115L/min pump with Jabiru 5100 installations.

Yes. It is entirely possible to integrate a heating system into your aircraft. Adding a heater core, and extra piping into the cooling system provides your with the bare essentials in creating a cabin heater.

In extremely cold environments it may be wise to include an electric pump controller as apart of your installation. Also the water pump may be turned off depending on the electrical setup.

Rotec press the valve seats into the heads the same way Jabiru or any other head manufacture would. The press we use is the same we have been using on our radial engine heads since 1999, and we have never had a valve seat fall out! We use around a 0.15mm interference between the valve seat and the head.

But the press fit has nothing to do with why air-cooled Jabiru heads being susceptible to valve seats falling out. The stock air-cooled aluminum heads simply get too hot and expand at a greater rate than the steel valve seat, this gets to the point where the interference between the seat and the head disappears and thus the seat falls out!

This can not happen with the liquid cooled heads as operating temperature are too low to get a significant differential in expansion. Our liquid cooled heads run at about the same temps as a modern water cooled car does (80 – 90 °C).

Rotec Aerosport offer warranty on our liquid cooled heads and items included. For Jabiru warranty it is advised you contact Jabiru. Keep in mind receiving warranty from Jabiru is almost impossible anyway. We are more interested in making your engine last and run at reliable temperatures rather than worrying about warranty!

Yes, we have a good installer in the USA. Any one who can install a standard Jabiru head can install ours also, as it is a similar installation process. It is not a difficult job. Our heads are NOT certified they are an experimental product. So anyone is allowed to install them.

Please see the LCH installation manual for more information on installation. Also see the Documentation tab in the Liquid Cooled Heads page, for more LCH documents and information.

Any 2 port radiator, without integrated filler port can be used. A small motorcycle radiator or one similar to that in the Rotax 912 will be ideal. The reasons that the radiator must not have a radiator filler port, is due to most installations not having the radiator at the top of the cooling system. This means the coolant must enter the system from a separate filler neck located at the top of the system. For more information about installing an LCH system refer to the LCH Installation Guide.

Please refer to the LCH Installation Guide.

We cannot supply a capacity for your LCH system because there is no standardized setup. The following values are capacities for the average installation including; a 200mm x 300mm radiator,  pump, piping, head volume ect. The average installation has the radiator located about 1 meter from the rows of heads.

• Jabiru 2200 ≈ 2.5 L (85 fl oz)

• Jabiru 3300 ≈ 3.5 L (120 fl oz)

• Jabiru 5100 ≈ 4.5 L (155 fl oz)

We recommend a coolant mix of 50% water and 50% antifreeze (ethyl glycol). This gives you a boiling temperature of 107 °C (225 °F). Increasing the percentage of antifreeze in your coolant mix will increase the boiling temperature, although it will degrade cooling performance in a short time. This is due to a build up of solids from the antifreeze on the walls of the cooling core. If higher boiling performance is required we recommend using a waterless coolant such as Evans NPG+ Waterless Coolant. Evans claim a boiling temperature of 190 °C (375 °F) allowing for maximum protection during high altitude flight.

Yes, they are no longer required as heat is now removed from the heads the radiator via the the coolant. Although they can be retained I choose despite being redundant.

Yes. Adding a Rotec Throttle Body Injection system to your engine, along with the the Rotec Liquid Cooled Heads will further increase engine performance. Along with a cooler running, and therefor more reliable engine, the TBI will increase the performance of the fuel system, and as a result increase power output.