Fuel in the oil in a small amount is just what happens with a high compression race engine. Even more so when its cold because your pistons haven't expanded yet. Thats why we have vents out of the valve covers for the combustion thats gotten past the rings. If combustion is getting by, so is fuel. I recommend not using real high dollar oil and change it after every other race. I use valvoline 20-50 racing and a recleanable oil filter.