It was running WITH NO OIL ?!?!???!?!?
There's you're problem mate, she's possibly stuffed.
If this started after running without oil, timing chain won't be the issue here. It will never be the valves.
You will almost certainly have damaged the engine internals.
I gotta laugh at Ju's answer !!
Have you checked your spark plugs and leads?
Have you checked your fuel filter?
Is there a lot of grey/black smoke coming from the exhaust?
If yes, it's getting too much fuel.
Do you fuel up with "cheap" fuel? this can cause injectors to become clogged, that...