Rotec LCH to suit all Jabiru Engines.
*Maximum CHT based on running engine at wide open throttle on engine test stand. Assuming correct installation.
Though the Jabiru engine is well designed, our research has found the following issues can occur when running heads at elevated temperatures:
- Head distortion (creeping), due the Aluminium alloy yielding
- Leaking heads, resulting in poor compression and loss of performance
- Chronic head detonation
- Valve recession
- Cylinder stud failure, directly attributed to detonation
- Head seating recession
- Valve failure
- Significantly reduced TBO
Previously, temperatures were combated by running excessively rich fuel mixtures to decrease head temperature, also leading to detonation. This wasn’t enough to alleviate the problem, and additionally increased fuel consumption. It was devised that increasing the cooling capacity of the engine eliminates all problems related to temperature. The most cost effective solution is to replace the entire head with a water cooled alternative.
Water Cooling vs. Air Cooling
- Water has more than 20 times the thermal conductivity of air (ability to conduct heat).*
- Water has over 4 times the specific heat of air (the amount of heat it takes to raise the temperature by 1°C).*
- Opposed to removing heat from the surfaces of the head in a constricted cowl area, a water jacket, gives the ability to remove heat directly from the hottest part of the engine; the exhaust valve.
- Due to cooler heads, yielding no longer occurs, and head bolts will not need to be re-torqued.
*Applies to all applicable temperatures
During the design process the following objectives were set:
- Re-torquing of heads bolts no longer required
- Better compression creating more power
- Head temperatures run between 80 – 110°C (175 – 230°F)
- Stop recession of cylinder heads & valves
- Stop ovality of cylinders
- Eliminate detonation
- Prevent shock cooling
- Minimise wear on valves & guides
- Avoid costly top end repairs before TBO
- Perfect CHT spread across all cylinders
- Make the advertised TBO achievable
- Use tougher grade 6000 series Aluminium alloy
- Adopt a superior structural design
- Offer the possibility of cabin heating
Testing and Final Product
The standard air cooled Jabiru 3300 engine will reach CHT limits within 2 minutes of high power static operation. The prototype LCH 3300 test engine, fitted with Rotec LCH ran for 4 hours continuously at WOT and the water temperature never exceeded 85°C (185°F). The CHT measured under the spark plug of the rear most cylinder peaked at 110°C (230°F). These tests were repeated over a period of 2 weeks of solid ground running and the results were the same every time. The ambient temperature during these tests peaked at 31°C (87.8°F). Needless to say the results not only met but exceeded our expectations. After around 30 hours of ground running it was decided to install the engine back into the SP6 Jabiru airframe where it came from and take it for a fly! See the third party testing in this testimonial.
Jabiru Liquid Cooled Head Kits
However many cylinders, or lifter type, Rotec Aerosport can upgrade your Jabiru engine.
Jabiru 2200 4 Cyl LCH Kit
Jabiru 3300 6 Cyl LCH Kit
Jabiru 5100 8 Cyl LCH Kit
|All Jabiru Liquid Cooled Head Kits by Rotec Aerosport come with all parts required to accommodate original Jabiru components. Only necessary replacement parts have been provided to keep the user price to a minimum. Liquid Cooled Heads come with new; valve guides, valve seats, head bolts and head bolt washers.|
Get your conversion under way, without a delay!
Hose & Clamp Kit
15 L/min Electric Pump
80 L/min Electric Pump
Recommended for most 6 cylinder installations. Fiberglass air ducts can be deleted from installation.
115 L/min Electric Pump
Recommended for all 8 cylinder installations.
Why stop at liquid cooling?
Engine Cowl Scoop
|Increase the fueling capabilities of your Jabiru engine, click here for more information!
||Available for Jabiru SP6, J230 & J430.
Water Temperature Kit
Jabiru LCH General FAQs
Jabiru aircraft engines are popular among the sport aviation community. Rotec have recognized that the engine is well put together, although the lack of cylinder cooling is where most of the serious issues arise.
Careful operation of the air cooled Jabiru is required to avoid permanently damaging the cylinder heads or other parts of the engine. The Rotec LCH conversion eliminates technical issues relating to head temperatures, therefore greatly enhancing engine reliability.
Rotec press the valve seats into cylinder 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 conception, and we have never had a valve seat fall out! A 0.15mm interference is used between the valve seat and the head.
Although inappropriate interference is not the culprit to why a head can be susceptible to having its valve seats fall out. The standard Jabiru air-cooled head simply get too hot and expand at a greater rate than the steel valve seat. The temperature high enough that 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 expansion. Liquid cooled heads run at a similar temperature that a modern water cooled car engine, around 80 – 90 °C (180 – 200 °F).
Several aircraft are fully operation. Go to our LCH Projects Page to see some of our documented customer projects. Over 500 heads have been sold as of mid-2014.
Terry Ryan of NSW, Australia has 120+ hours on his LCH conversion and loves it! He flies all day at around half the CHT of an air cooled Jabiru. Cylinder compression of his old engine become like new switching to Rotec Liquid Cooled Heads. Terry Ryan has also converted his second Jabiru engine to LCH after such success with the first.
LCH will fit any Jabiru 3300 or 2200 engine and are not designed to fit the very early Jabiru 1600 engine.
See the LCH installation manual for a step by step installation procedure.
Jabiru cannot supply engines or aircraft directly with Rotec Liquid Cooled Heads installed. International customers wishing to purchase a Jabiru Aircraft with any Jabiru Performance Upgrades installed, the following options are available:
- The airframe with engine and Rotec LCH kit are sent to your location. The conversion is performed at your leisure, something many of our customers have done.
- The airframe is sent to your location. The engine is sent to Rotec. Once the engine is converted, it is returned to you to install onto the airframe. This saves on shipping the airframe from Jabiru, to Rotec, to you.
- Rotec purchase the airframe with engine and send to our facilities. The aircraft will be fully assembled (if necessary), converted and test flown. Once complete, the aircraft is sent to your location. With this option, significant discounts can be offered on other upgrades components.
Contact us for pricing.
Anyone who can install a standard Jabiru head can install a Liquid Cooled Head, as it is a similar installation process. It is not a difficult job. Liquid cooled heads are not certified and are an experimental product, so anyone is allowed to install them.
Experienced installers are available in the USA.
If desired, Rotec can fit new or used valves train components (i.e. valves, valve springs, spring retainers, valve collets, base washers and rocker arms), to LCH on behalf of customers. New components can be purchased through Jabiru Aircraft Pty. Ltd. Customers wishing to add valve train parts already in possession to their LCH order, can send them to our facilities.
Note: Hydraulic or solid lifter engines use different rocker arms. You must inform Rotec of you engine type to ensure the correct rocker arm is used. Click here to learn how to determine your engine type.
It is preferred that hydraulic lifter engines have their valve train components sent to our facilities for installation. Hydraulic lifters have approximately 4 mm of adjustment. This can make it difficult to have the correct seat depth without having valve to match them to.
Rotec is able to install any Jabiru upgrade system to your engine or aircraft at our facilities.
Each Rotec Liquid Cooled Head is approximately 250 g (8.8 oz) lighter than the standard Jabiru 2200 air-cooled head. Standard Jabiru 3300 air-cooled heads are equal in weight to Rotec Liquid Cooled Heads.
The added weight of coolant, piping and radiator, is practically negligible. To date no installation has required any weight adjustments to balance the air frame, so minor changes to the center of gravity are negligible.
See weight comparison of a Jabiru 2200 head vs a Rotec LCH head for more information.
Rotec Aerosport offer warranty on our liquid cooled heads and items included.
For information on Jabiru warranty, it is advised you contact Jabiru. Keep in mind receiving warranty from Jabiru is almost impossible anyway. Rotec are more interested in making your engine last and run at reliable temperatures, rather than worrying about warranty!
Jabiru LCH Technical FAQs
Rotec Liquid Cooled Heads fit all Jabiru 2200, 3300 and 5100 engines (4, 6, or 8 cylinder), hydraulic or solid lifter and with or without rocker oilers.
For later model hydraulic lifter engines, the external rocker oiler ports are bridged with rubber tube as no oil feed is present. Other than that, there are no difference between liquid cooled heads installed on a hydraulic and solid lifter engine.
All stock Jabiru components are transferred to the LCH head, i.e. rockers, valves, push rods, push rod tubes, spark plugs, as these are all retained and located in exactly the same location.
To identify whether an engine uses hydraulic or solid lifters:
- Remove one rocker cover from any head
- Observe the rocker arms inside
- If there are valve adjusters on the rocker arm, the engine uses solid lifters
- The absence of valve adjusters will indicate the engine uses hydraulic lifters
Note: Valve adjusters are used to adjusting valve clearances, traditionally consisting of a grub screw and a lock nut to maintain tension.
See the following video for more information:
A Jabiru engine upgraded to Liquid Cooled Heads will run far better on automotive gasoline (Mogas) than an engine running standard air-cooled heads. The reduced cylinder head temperatures will greatly diminished the risk of detonation. Mogas is more susceptible to detonation than aviation gasoline (Avgas) due to its lesser octane rating and inferior purity.
We cannot recommend a coolant capacity for your installation as 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.
Electric Water Pumps (Recommend):
|80 L/min pump for standard Jabiru 3300 installations.|
|EBP15||15 L/min pump only used in Jabiru 2200 installations, or Jabiru 3300 installations with exceptional radiator performance and fibreglass baffling retained.|
|115 L/min pump used with Jabiru 5100 installations.|
Note: Tests have shown that with the electric pump switched off, a Jabiru 3300 LCH conversion can fly at reduced power for approximately 45 minutes within safe temperatures.
Mechanical Fuel Pumps:
A mechanical water pump could be added and driven from the Jabiru engine accessory pad. However, it has been found that an electrical water pump is just as efficient and easier to install. A redundant pump can be installed if desired, although is in no way mandatory.
The filler neck should be mounted at the highest point of the installation.
Please refer to the LCH Installation Guide.
Cooling performance will be improved if any characteristics go beyond the following minimum recommendations:
- Jabiru 2200 – 500 cm^2 (77 in^2): e.g. 25 cm x 20 cm x 4 cm
- Jabiru 3300 – 600 cm^2 (93 in^2): e.g. 30 cm x 20 cm x 4 cm
* Recommended total frontal area from the front of the plane. Cooling performance depends on airflow. Can be distributed amongst multiple radiators.
- Single Inlet Port Size: 19 mm (3/4″)
- Single Outlet Port Size to Fit Water Pump:
- Filler Port:
- Without Integrated Filler Port – Radiator must be mounted below the coolant level. Coolant instead enters the system from a separate filler neck located at the top of the system. These are supplied as standard with LCH piping kits.
- With Integrated Filler Port – Optional, for top mount radiators where a header tank is not used
Radiator(s) are not supplied with LCH kits as all installation requirements vary. Use small motorcycle radiators, otherwise performance racing radiators can be fabricated relatively cheaply. You can even adapt a Rotax 912 cooling system.
For more information about installing the LCH system, refer to the LCH Installation Guide.
Circulation schematic/plumbing circuit can be found in the LCH installation manual.
Fiberglass air cooling ducts can be removed from LCH installation using appropriate liquid cooling. They’re no longer required as heat is now removed from the heads via coolant and dissipated through the radiator. They can be retained if desired despite being redundant.
After warm up, CHT’s should not be below 70 °C (140 °F) during operation. In extremely cold environments where this likely, it may be wise to:
- Include an electric pump controller to limit the pump flow rate
- Turn off the water pump when it is not required. A cut off switch can be incorporated into the electrical circuit.
It is entirely possible to integrate a cabin heating system into your aircraft. Adding a heater core, and extra piping into the cooling system circuit provides your with the bare essentials in creating a cabin heater.
Click clients name to proceed to their project page. Go to the Jabiru Projects Page to see more LCH Projects.
|Jabiru SP6||Terry Ryan 03-2011||VIC, Australia|
|3/4 Scale Spitfire||VIC, Australia|
|Avoket pusher||Mike Sharples Pusher 06-2011||SA, Australia|
|Martian Hone||Jabiru J230||QLD, Australia|
|Rotec LCH Installation Guide||Learn what is needed and how to install a liquid cooled head kit.|
|Testing By Terry Ryan||A detailed report/testimonial created by Terry Ryan on his Jabiru SP 6 with a Jabiru 3300 engine. Shows temperature rages in many different flying scenarios.|
|Mike Sharples Pusher 06-2011||Email by Mike Sharples explaining the results of his LCH installation.|