There is a small dot about 1/8" diameter cast into the front of the piston near the wrist pin. Also a letter "R" cast into the rear of the piston.
In a 2.5L the handle end faces up.
Piston rings are always installed with the numbers up toward the top of the piston
closest to the pulley/belt.
Get New piston rings!
you need to bring cylinder 1 piston up to top dead center on compression stroke then turning the oil pump drive shaft so the distributor rotor faces #1 on the distributor cap.
Its the cylinder closest to the serpentine belts
Clockwise.
On the 5.0 liter and 5.8 liter V8 engines , # 1 on the distributor cap faces to the REAR and slightly towards the drivers side On the 4.9 liter straight 6 cylinder , # 1 on the distributor cap faces AWAY from the engine
By interference, if you are referring to the valves. The 1.8 liter is a non interference engine. If the timing belt brakes, then the valves do not interfere with the piston. They do not try and occupy the same space. The 1.9 liter engine is an interference engine. If the timing belt breaks then the valves will occupy the same space as the piston and they will hit each other.
You might have bad piston rings, main cause of that because once you wear your rings out your gas is then able to seep past your piston rings into your oil and into your pan.
Bad spark plug or wireBad valve (do a compression test)Bad piston "
A 2.0 liter engine means that the total volume of all the cylinders is 2.0 liters, or a different way to put it, a 4 cylinder that is a 2.0 liter has 0.5 liters of volume from when the piston is at the top of the cylinder to when it's at the bottom of the cylinder.