CHIPSHAPER Posted November 6, 2006 Share Posted November 6, 2006 Hi All, I have an EA-81 in my aircraft with a dry sump, and it is using oil at 1 Ltr per hour! The compressions are all on or around 160 and it was reboared 40 hours ago with new pistons etc. We fitted new valve oil seals but it still drinks oil! Any help or advise would be greatly recieved. There are no oil leaks that are visible! Regards Paul Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 6, 2006 Share Posted November 6, 2006 How's the PCV system? Are you using a custom manifold? The PCV system needs to be routed correctly or the engine will suck oil from it. If you are using a stock manifold get a new PCV valve from the dealer. Aftermarket valve's are known to cause oil consumption. GD Quote Link to comment Share on other sites More sharing options...
CHIPSHAPER Posted November 7, 2006 Author Share Posted November 7, 2006 Thanks for the quick reply. I have a NSI Manifold and engine conversion and I think the PCV you mention is blanked off, but could you explain what the PCV does as it may well be the route of the problem? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 7, 2006 Share Posted November 7, 2006 PCV (positive crankcase ventilation) keeps the crankcase from being pressurized by the pistons. It's a one-way check valve that allows the crankcase to breathe into the manifold. This keeps the combustion gasses that leak into the case from getting out into the atmosphere. Sometimes these valves can have a weak spring (or get stuck with carbon build up) and the engine vacuum will suck oil up through the valve covers into the intake and burn it. Since you have a manifold that does not have a PCV, this may not be your problem, but how are your breather tubes routed from the valve covers? Are they routed to the air cleaner or do they have their own filters like so many of the V8's like to do? Any evidence of leakage anywhere? The rings don't often fail on these engines.... if it's been rebuilt were the rings run-in properly to assure a good seal with the cylinders? How do the plugs look? Any evidence of oil fouling or burning? GD Quote Link to comment Share on other sites More sharing options...
CHIPSHAPER Posted November 7, 2006 Author Share Posted November 7, 2006 The valve covers do not have a breather and the engine puffs a small amount of white smoke when you rev it from tickover but the plugs look great. Also there is an oily smoky residue on the underside where the exhaust exits. Paul Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 7, 2006 Share Posted November 7, 2006 Valve covers have no breather line? That doesn't seem right. If the crankcase can't breathe the pressure will push oil past the rings and it will be burnt - that might explain the residue on your exhaust... GD Quote Link to comment Share on other sites More sharing options...
CHIPSHAPER Posted November 7, 2006 Author Share Posted November 7, 2006 The engine is dry sumped so I think it breaths through the oil tank. Paul Quote Link to comment Share on other sites More sharing options...
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