What happens when the intake valve opens?
When the inlet valve opens, atmospheric pressure forces the air-fuel charge into the evacuated chamber. As a result, the combustible mixture of fuel and air fills the chamber. The resulting pressure pushes the piston down with several tons of force.
What should I do if I need to replace an intake valve?
Instal the valve stem seals fisrt (very careful not to damage any of them, best to buy a few extras just in case). Put motor oil on the valve stems before you put it back in and use a dab of grease to hold the keeper in place while you release the valve spring compressor.
Can You recut intake and exhaust valve seats?
If you wanted to go first class, you can have an automotive machine shop recut the faces on the intake valves, and the intake and exhaust valve seats. though if they are not bad looking it will not result in any noticeable benefit, only if they are really beat up. if the last owner had the seats reground they should not be too bad anyway.
Can a valve be adjusted to factory spec?
Once the head is all together, yes the valves have to be adjusted to factory spec because you replaced parts and the relationship with them will be different. I usually do this last after I have the head on the engine.
Do you have to replace the valve seat in the head?
Usually this is not necessary, but it is a low cost way to resurface the valve seat in the head. Once the head is all together, yes the valves have to be adjusted to factory spec because you replaced parts and the relationship with them will be different.
How much does it cost to repair a bent intake valve?
Unfortunately, repairing bent or burnt valves is not easy. Valve replacement is a very large job requiring engine tear down. Because this is such a difficult task, the cost for valve repairs can reach above $5,000 in labor alone. This repair can take 35+ hours to complete, after diagnosis.
When to change the timing of the intake valve?
As intake air velocities increase with engine speed, the intake valve should close later to help pack more air into the cylinder. In theory, most VVT designs begin to change intake valve timing when intake air velocities begin to dramatically increase at 2,500 to 3,500 rpm.
How often do intake and exhaust valves close?
During the exhaust stroke, the piston will begin to head upward again, pushing the expended mixture through the now open exhaust valve. After the exhaust gases have escaped the cylinder, the exhaust valve will close and the intake stroke will occur again. This entire cycle occurs about 1,250 times per minute when driving at freeway speeds!
What does it mean when your VVT is not working?
It’s obvious that most VVT failures will affect intake manifold vacuum and result in a loss of low- or high-speed engine torque. When the camshaft is not responding to the positions commanded by the PCM, the PCM should store a camshaft-related timing P0340-series error code.