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Tappet Adjustment
Tappet clearances should be checked and adjusted if necessary in accordance with the Head Torque document (243kb). It is imperative to do this at 5, 10, 15, and 25 hours running for new and zero houred engines, after first checking head bolt torque. Valve clearances are 0.010" (0.25mm) for both inlet and exhaust. Thruster Owners The installation of the Jabiru engine in a Thruster is a little unique but many hours have now been put on them. A few considerations: The engine is exposed and therefore electrical components and in particular the Starter Motor, must be protected from the rain. It ain't waterproof! In damp weather, the carb de-ice system doesn't always fully keep the ice out for the engine. On descent and low power settings, it is important to keep some throttle on and 'test' the engine from time to time by blipping the throttle. Take care about shock cooling - school aircraft frequently run from full power to idle with a cold blast of air on the cylinders. Thrusters don't have the cylinders shrouded like cowled aircraft and so the engine can get a bigger blast of cold air than most. Top End Overhauls We are confident in defining these at 1000 hours on engines from s/n 711 (2200) and 119 (3300). This is also providing a number of criteria have been met. Costs are worked out depending on what needs replacing however in general, conrod bearings, cylinder hone, new pistons & rings, all 'O' rings, gaskets, new valves, heads reconditioned etc. Typically, parts would cost £900 for 2200 and around £1,500 for 3300. For a 2200 that works out at £1 per hour for parts for the engine fund! Tacho Its important to check that your tacho is reading correctly as interference etc and false triggers can give rise to false readings. An accurate tacho is important to give an idea of the power output from the engine, amongst other factors. Calibration is best carried out using an Optical tacho, available at Southery or at a good airfield near you! Common practice now is to take the Tacho impulses from one side of the alternator. For 4 cylinder engines you get 5 pulses per rev, and for 6 cylinder engines 6 pulses, however those with 3 phase alternators give 4 pulses. TBO Interesting facts of engine service time around Australia. There a many flying schools who have logged around 4000 hours with some in excess of 5000 hours and have produced many new pilots as a result. A high degree of maintenance has also been a factor in their success. Some of the engines had been overhauled at least 2-3 times. The usual interval between overhauls have been around 1000 hours. For engines from serial number 711 (2200) and 119 (3300), provided their service life meet a number of criteria, only a top end overhaul need be undertaken at 1000 hours. Bottom ends have proven to be particularly rugged. Tyres These get quite a hammering (especially with my landings!) so keep an eye on pressures. Low tyre pressures can cause tyre bulging giving rise to popped spats! Soft tyres can also lead to brake disk damage Teleflex Cables When installing these take care to ensure nothing is rubbing against the outer sleeve or tube outboard of the cable anchor. If any pressure is bought to bear, a large increase in control circuit friction will result. high hours aircraft will need to have these replaced (refer to manual).
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