Tonight I’ve been trying to get my head around where I am with the under revving and overheating issues with my blue head 582. Here’s where I’m at and what I’ll be doing next time I’m at the airfield….
Summary of known conditions in no particular order-
· Propeller. 12* pitch blocks on a 3 blade composite 68†Brolga prop, powered by a 582 blue head Rotax engine through a “B†reduction box 2.58:1 gearing. Propeller is second hand but in good condition. Number 1 blade weights 2 grams lighter than the other 2. Number one blade tracks 10mm to the rear of the other 2 blades at bottom centre of the propeller arc. No facility on this type of setup to adjust propeller blade tracking.
· Maximum revs 6200 WOT ever since brand new including during run in phase.
· Engine prone to overheating ever since new with temps wanting to climb through 80*c including during run in phase.
· The Bing 54 carburettor slides show synchronised and full movement through the entire throttle lever range. WOT position shows slide as wide open.
· Engine idles at 2000 RPM with vibrations felt until revs increased to 2200.
· Engine has 30 hours since new, as shown on electrically activated hour meter – true running hours possibly 27 or so.
· Tacho and water temp gauges are confirmed as reading accurate.
· Thermostat is confirmed as operating correctly.
· Enrichening circuits (choke) on the carburettors are functioning correctly with complete de-activation when levers returned to the ‘Off’ position. Engine starts with no trouble.
· All 4 spark plugs exhibit consistent tan/light brown colour, indicating correct fuel/air mixture.
· EGT gauges at 6000 RPM read 1100* identical on both cylinders.
· Engine runs on Caltex unleaded 91 Ron fuel at 50.1 mix with Castrol Active 2T 2-stroke oil.
· Air cleaners were brand new with the engine and are in as new condition.
· Carburettors were brand new with the engine and have not been altered in any way, or checked for synchronisation apart from visual inspection of slide operation on both carburettors.
· Exhaust system was brand new with the engine and has been slightly modified. Where the gases exhaust to outside air a 50mm long (or thereabouts) curved pipe has been added to direct the exhaust gases away from the wing skins. See photo in post # 52
· The 2 part radiators are the smaller version radiators from the old grey head 582 installation. New radiators were not purchased with the new blue head 582 engine.
Things to check when next at the hangar-
· Remove overflow bottle from the radiator coolant circuit to check if there is airflow interference from the bottle interrupting airflow around the radiators and engine. See photos.
· Fully inspect and check carburettors set up – All jets and needles, float levels, position of needle clip retainer in needle groove, position of white plastic retainer is above needle clip, pneumatic synchronisation of both carburettors, and full throttle slide movement (again).
· Fit larger test radiators on loan from Riley to ascertain benefit from larger radiator capacity.
· Check ignition pick up gap and timing of ignition.
Is there any other checks I should do at the same time?
Pud
