INSTRUCTION AND MAINTENANCE MANUAL FOR ... - Jabiru Aircraft

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Jabiru Aircraft Pty Ltd Instruction & Maintenance Manual Jabiru 3300 Aircraft Engine Hydraulic Valve Lifter Models Check carburettor linkages for full & free movement, correct positioning of stops and security. 6.4 Compression Check 6.4.1 Compression Gauge: Measure compression using a compression tracer. Readings are taken with fully open throttle valve at engine oil temperature between 30° & 70° C (90° to 160° F). If readings are below 6 bar (90 psi) a check of the pistons, cylinders, valves & cylinder heads must be undertaken. 6.4.2 Pressure Differential Test Check using a Pressure loss or leakage tester eg SUN or BOSCH tester; max.allowable pressure loss is 25%. As an alternative to a compression test, a pressure differential test (Leak down) can be carried out. This is a much better test of the condition of rings, bore, head sealing and valve. This is the normal test used in aviation and requires specific equipment. The test is carried out with the engine in warm to hot condition. Input pressure is best set at 80 PSI; a second gauge reads the differential. This is done with piston on TDC on the firing stroke. Note that the propeller needs to be restrained. A differential of lower than 80/60 (or generally, a 25% loss) indicates a problem. Problems can be better identified using the leak down: i) Blow by through the crankcase vent indicates worn rings or bore ii) Leaking from carby indicates a poor intake valve seal iii) Leaking from exhaust indicates a poor exhaust valve seal iv) Head leak indicates poor head to cylinder seal With the problem narrowed down, correction work can more easily be carried out. A Pressure Differential Tester can be made by placing an orifice of 1 mm ID and 3mm length between two pressure gauges. This will give the same result as with the above instrument. Max. pressure drop is 25%. CAUTION: Poor compression can be an indication of a serious problem. For example, continued operation with poor compression due to a poorly-sealing valve can lead to eventual valve failure and heavy damage to the piston, con-rod, barrel and head. If low compression is found which cannot be solved by reference to the Troubleshooting section, please contact Jabiru Aircraft or our local authorized representative. This document is controlled while it remains on the Jabiru server. Once this no longer applies the document becomes uncontrolled. REVISION 0 1 2 3 4 5 6 7 8 9 Dated : Apr 2011 Issued By: DPS Page: 24 of 53 L:\files\Manuals_For_Products\Engine_Manuals\3300_engine_manuals\Hydraulic_Lifters\Working_Copies\JEM3304-9_I&M.doc
Jabiru Aircraft Pty Ltd Instruction & Maintenance Manual 6.5 Ignition System Figure 4 – High Tension Lead Connections Jabiru 3300 Aircraft Engine Hydraulic Valve Lifter Models Figure 4 above maps the connections between the distributors and the spark plugs. Do not use steel or brass brushes for cleaning & never sandblast plugs Clean with plastic brush in a solvent. This document is controlled while it remains on the Jabiru server. Once this no longer applies the document becomes uncontrolled. REVISION 0 1 2 3 4 5 6 7 8 9 Dated : Apr 2011 Issued By: DPS Page: 25 of 53 L:\files\Manuals_For_Products\Engine_Manuals\3300_engine_manuals\Hydraulic_Lifters\Working_Copies\JEM3304-9_I&M.doc
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INSTRUCTION AND MAINTENANCE MANUAL FOR ... - Jabiru Aircraft

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