Can valves damage Pistons?
Piston damage has been caused by contact with the valves of that there is no doubt. That said it would be very unlucky to damage the piston in such an event. In most case’s the valves will be at an angle to the piston that is about to strike them. Pistons tend to be very robust around the crown, valve stem not so much.
Why would a piston hit a valve?
Valves hitting pistons means a timing issue. If the car has a solid metal chain and not a rubber belt the chances of it ever going out of time as a result of driving habits are so low it’s probably not measurable.
Do Pistons close the valves?
Continuing the piston’s trip through the overlap phase and back down the cylinder for the intake stroke, the intake valve will go fully open and start to shut. After the piston reaches BDC and starts its’ way back up the cylinder for the compression stroke, the intake valve will go closed.
What is the maximum piston to valve clearance?
A safe rule of thumb is . 080-inch for intake valves and . 100-inch for exhaust, which requires a little more clearance because of the increased heat factor.
Will bent valves cause no compression?
A number of things can cause an engine to lose compression, and just about all of them involve mechanical failure of some kind. So, bent valves, a hole in the top of the piston, or broken piston rings can cause a loss of compression that can equate to a no-start condition.
Are valves closed at TDC?
It’s up to you. Both valves should be closed if it’s TDC at the end of the compression stroke. If it’s TDC at the end of the exhaust stroke, you should be in the valve overlap zone, with the intake valve partially open and on its way to opening fully, and the exhaust valve partially open on its way to closing.
Does a piston stop moving?
No, the piston never stops “moving” in a running engine. It changes direction and the instantaneous linear velocity equals zero at TDC and BDC but “movement” or motion involves more than simply instantaneous velocity.