I have a 92 dohc 240sx and latley ive been hearing this loud ticking coming from the back of the head.. Also sometimes at stops ill get a puff and blue smoke not every time. But it always smells like oil and is always ticking sometimes it feels like its draggin the engine down. Im wondering if there is any cleaner or something i can do without having to rebuild it to cure or improve this issue..

Thanks

Evan