LOL. I don't think that you'll find too many on here that can diagnose that issue for you. What kind of engine/car is it? I'd be willing to bet that you have one of two problems: You have a bad valve or two, which depending on how bad it is, means that the piston is hitting the valve or it is a knocking sound due to using too low octane gas. If it is situation one, your going to spend lots of money. If it is number two, try running some premium gas (91+) through it.
2.) Pre-detonation (esp. if your car has a turbo or supercharger). This means that the gas vapor (because of bad ignition timing, bad AFR, low-octane fuel, etc) is detonating before the cylinder hits top dead center. This is VERY bad for your engine and can cause a rod to go through the block if you push it.
3.) No oil (although if you have hydraulic lifters this would not matter).
it all depends on the car make, different manufacture got different valve design,
some uses hydrolic lifters, whicn can casue ticking noice if they fail ( owned a mazda 626, which is a common problem for that model), but other issue that mention above by other gents is a possibility.
will suggested to find a pro to check it otu for u to eleminate all the guess work.
I worked in the autoparts retail sales area for a few years. I've seen random 'ticks' come mostly from the accessory drive of the car (read belt, pullys and anything they connect to). Typically its a bad bearing, they don't always produce a squeal, sometimes they do tick. Other times it is internal to the engine, a lifter, rod, even a PCV valve with a leak.
Without hearing the sound, and moving around the engine compartment to hear where it is louder or softer, and without knowing what kind of car it is; it will be impossible for us to pinpoint the culprit.