Engine baffles have a critical role in ensuring that the engine is correctly cooled. Engine baffles and cowls are designed to provide an air seal between the top and bottom of the engine. This air seal ensures that the cooling air is correctly directed through the engine, oil cooler and engine compartment to guarantee the proper cooling of the engine.
Just as a leak in the radiator in your car can cause your car engine to overheat, leaks in engine baffles can cause your aircraft engine to overheat.
Poorly fitting or maintained engine baffles can result in the cooling air going around instead of through the engine.
Leaks can cause uneven cooling of the engine. One or more cylinders may be operating at substantially higher temperatures than the other cylinders.
A multi-channel Cylinder Head Temperature gauge is the best way to verify that all cylinders are operating at similar temperatures. For continuous operation the Cylinder Head Temperatures should be kept below 400°F and preferably below 380°F.
High cylinder head temperatures can cause:
Faster wear rates of top end engine components, in particular exhaust valves and valve guides.
Cylinder head cracks.
Oxidised engine oil and glazed cylinder bores.
Things to look for when inspecting and refitting baffles include:-
Ensure all baffles are correctly fastened to the engine.
Make sure no baffles are missing. Pay particular attention to small baffles that need to be fitted around oil coolers, engine mounts, inter-cylinder baffles, etc.
Seal excessive gaps where baffles are attached to the engine with a suitable flexible sealant. Check that large gaps are not left around the inter-cylinder baffles.
Check the baffle rubbers have not become worn or torn.
Check that when the cowls are fitted the baffle rubbers form a good seal. (Dust tracks on the inside of the cowl can indicate where leaks are occurring.)
Check that the cooling air pressure in flight is not folding baffle rubbers back and dislodging them from their correct position.
Keeping your engine baffles in good condition will benefit your engine and save you money in the long run.