I am not certain on the manufacturer of your clock although it looks a lot like a Seth Thomas clock I have and it is also a 8 day.
You can usually adjust the speed of the clock by making the pendelum longer to make it slower or shorter to slow it down if there is an adjustment nut on the bottom of the pendelum bob. If you do not see that many times it is marked + and - somewhere on the back plate of the clock where either a small key or screw driver will be used to adjust the speed.
If it is losing time it more than likely would need to be adjusted shorter or to the + direction in small amounts until you see it running at correct rate. I normally adjust the pendulum just a slight amount maybe 2 turns or 1 turn and then wait for 24 to 48 hours and see if it is loosing or has changed and how much.
If I see your clock in anything I have I will reply with further information.
it need's a new door by: Anonymous
it need's a new door or it will get dust on the face