Valves Knocking

[Kennedy200]

I have a 1995 Ford Aspire with 120000 miles on the odo. I need to keep this car on the road since I cant afford a new car at the moment.

Whenever the weather gets hot the valves knock real bad.

I don't get any warning lights on the dash. So, I assume that the EFI is working correctly.

I have serched for bad vaccume lines and found them all to be in good shape. I will continue to look for bad hoses.

I have tried different brands gas and different grades of gas, and nothing changes. It still knocks.

I have replaced the PCV valve, and spark plugs, dist cap and rotor. The wires are a year or 2 old, but they are in good shape.

I also notice a smell of raw gas when I put the car in the garage. I'm not sure if its related or not?!?!

Could the timing belt be the culprit????