Can you bend a valve by hand cranking?
Registered. Yes, I manually rotated a crank years ago after lining up cam gear marks to center valve cover arrows. Resulted in bent front intake valves and once the starter got involved, a valve snapped off and locked against the piston. Moral: Some FSM diagrams are misleading, and it’s possible to bend valves by hand.
Can a starter bend a valve?
Yes the starter is strong enough to bend valves and if the crank is turning and not the pulley, then yes the piston will hit the valves. Pistons are moving up and down and valves are stationary. More damage is done in an interference engine by trying to restart it when a timing belt breaks.
How hard is it to bend a valve?
It is possible to bend valves with a ratchet, but you would have to try pretty hard. If you were careful and calm when you felt the contact, you should be okay. Best way to find out at this point is to put on the belt and give it a go. You could do a leakdown test, but that requires a few special tools.
Can a broken timing belt cause bent valves?
Interference vs. non-interference engines. The level of damage caused by a broken timing belt can depend on the type of engine you have in your car. A non-interference engine provides clearance between the valves and pistons, so if the timing belt breaks, you might end up with bent valves, and you might have to have your cylinder heads rebuilt,…
What happens to a valve when it is bent?
If a valve is bent, then it will be the valve stem, not really the valve head. When a valve is bent it will not easily slide up and down the valve guide, creating force against the cams or hitting the piston each time the piston comes up.
What happens to the timing of the piston and valve?
The precise timing of the piston and valves continues similarly through all four cycles. And this timing is closely calculated to provide efficient engine operation. If the cam loses valve timing just a few degrees, however, your customer will notice a severe power loss or a no-start condition. Engine damage may occur, as well.
How can I tell if my engine timing is wrong?
You can also confirm a timing problem by checking engine compression. If the valve timing jumps, you’ll get little or no compression equally in all cylinders. As a result, the engine often cranks too easily, with little starter current draw.