My W5 engine was rebuilt before I purchased this project. I put 5 liters (about same as 5 US quarts) of oil in the engine.
My oil dipstick did not come up to the full mark. First startup was only for about 10 -15 seconds. Second start-up a day later was about the same. One day later when I went into my shop there was oil all over the floor. It appeared to come from the rear of the engine. No drips from the oil pan.
Checking the archives I see the oil capacity should have been 4 quarts??
What kind of seal or arrangement is there on the rear bearing to prevent the oil from leaking out.
Have I damaged anything??

What would be my next step?

Thanks,

Where Are You From? Kamloops BC Canada

Do You own a car built by Durant? 1926 Star (being restored to a delivery service van)

Actually, there is NO oil seal as such. Oil is rerouted back into the engine by a spinning ring. This ring is part of the crankshaft and as oil tries to move to the rear, it is deflected by this spinning ring and tossed into a circular trough then directed back into the crankcase.
Do not rely on the oil level floater, it is notoriously inaccurate.

Where Are You From? Texarkana, TX

Do You own a car built by Durant? Several