Worn valves will not seal completely, will not open completely, or open as far as they should.
This will cause incomplete combustion, backfire of exhaust gasses, release of compression, and escape of oil into the combustion chamber.
Engine will lack power and smoke.
Worn engine rings or valves Worn engine rings or valves
It sounds like the engine timing. The sound is coming from your engine valves. They're not in synch with the rest of your engine. It could also be that the valves are worn out. I'd check the timing first, then the seating on the valves.
If engine is losing compression it is likely the rings are worn and need replacing. The valves are likely leaking too and need replacing.
A clicking noise in the engine of a 91 Ranger could indicate a problem with the valves. A valve lifter in the engine may be worn or stuck.
You have a compression loss probably resulting from worn rings. An enging rebuild should fix this problem. first check that the pcv valves are operating correctly as this could be the problem..
engine is worn out, carburetor secondarys not properly adjusted,worn valves,and the list goes on.
Valves are not seating properly. Worn piston rings, cylinder sleaves and or blown Head gasket
When you are operating it.When you are operating it.
Three possibilities. Overfilled with oil. Worn cylinder or rings. Worn valve guides. On most smaller engines, it's cheaper to replace the engine or the short block. If the engine has overhead valves and the valve guides are worn, a short block won't fix the problem.
Worn piston rings, Burned valves, Sticky valves,
Worn engine rings or valves allowing oil to enter combustion chamber
you cant if rattling noise occures its a worn lifter very common on 3.1 motors