Hi, Looking at the marks to the top of the oil pump shaft and the roll pin in the bottom of the dist drive I would hazard a guess that the dist is not going down into the front cover far enough. It's engaging with the camshaft gear which is why it runs OK, but is not engaging with the oil pump shaft. They can be a bit fiddly sometimes, it happens to the best of us, try keep turning the pump shaft a little bit either way until it does go down properly. Can you take a picture of the base dist installed? Are you thinking that the dist shaft has moved up into the dist housing? If it had you probably wouldn't get the dist cap on.