Hi Guys I’ve just finished an engine oil change on my dry sump 1980 308 GTB… after running the engine, I undid the sump plug and, to my surprise, out gushed a couple of litres of oil. I took down the sump, just to be safe, cleaned the screens on the oil pick ups and made sure the scavenge tubes were unobstructed, but there was nothing obvious, so back it all went. My question is, is a couple of litres normal in a dry sump car, with it just being drain down from the heads, or have I got a scavenge pump issue? Thanks Paul
Maybe I am not understanding correctly, however, there will always be oil in the engine sump. When you change oil in a dry sump, you need to drain both the oil tank and the engine sump as there is oil in both areas. After you changed the oil, you opened the engine sump and found oil? That is perfectly normal if I understand your question properly.
If you had an issue it would be more apparent while driving I would think. A scavange pump has about twice the capacity of the supply pump and during normal running would keep the crankcase very low, thats the idea. How much was in there when you pulled the plug has a few variables. One being how long you ran it and another being how long between shut off and pulling the plug. After sitting long enough nearly all the oil from the tank winds up back in the crankcase.
Thanks for the quick responses - yep, I drained the oil tank too, to change the oil, which still had the full volume of oil in it. I drained the sump about 10-20 minutes after turning off the engine and, later, when I had the sump off, there was oily a very slow drip….drip…drip back from the cooler. Rifle driver, as you rightly point out, the scavenge pump should have twice the capacity of the supply pump, so level should be down to the level of the oil pick ups. My concern is, therefore, the sheer volume of two litres of oil that was in the “dry” sump, and whether this is just normal drain-down from the cam boxes on shutting down, or whether I have a scavenge problem with the return pump.
