[′in‚let ‚valv] (mechanical engineering) The valve through which a fluid is drawn into the cylinder of a positive-displacement engine, pump, or compressor. Also known as induction valve.

The intake valve opens when the piston reaches the TDC; compressed air from high pressure tank rapidly flows into the cylinder. The pressure inside the cylinder rapidly increases to the intake pressure. Compressed air no longer flows into the cylinder, when the intake valve is closed.

There are two types of engine valves; intake and exhaust valves. The intake valves of course let air in, and the exhaust valves let exhaust air out. Once the piston goes through the compression and firing stroke, the exhaust valve will open and let the exhaust out.

Valve is opened before time so that the time spent in opening the valve is over before T.D.C. By opening the valve after B.D.C. the mixture of air and petrol is stopped from going out through the carburetor by back pressure.

Prior to the piston reaching TDC, the intake valve starts to open. The previously created vacuum in the combustion chamber will draw fresh air/fuel mixture into the combustion chamber and some will even escape into the exhaust port. This will ensure that all of the spent gasses are removed from the combustion chamber.

Valve timing is an important part of the internal combustion process as it regulates the flow of fuel and air in and exhaust out of the combustion chamber – that’s the part of the engine where the pistons compress the fuel and air for combustion.

The dial indicator should be set to zero if you want to find exact TDC. The crankshaft needs to be turned counterclockwise about 90 degrees. Slowly rotating the crankshaft clockwise until the indicator appears.

If the valve timing is incorrect, not only will the engine not run, but the piston could smash into the valves, causing catastrophic damage. Usually, the result is bent valves and damaged pistons. A Ducati’s timing belts, exposed for all the world to see. If piston-to-valve timing is off, this is the result.

Higher RPM – The main advantage of having a variable valve timing technology is the increase it will provide in your engine’s revolutions per minute. When you step on the gas pedal to accelerate the vehicle faster, it will require more RPM to sustain this demand.

Valve overlap is designed into the engine and is most useful at higher speeds. At higher speeds, the extra amount of intake charge brought into the combustion chamber provides a substantial increase in available power. The amount of time that both valves are open in directly related to engine rpm.

Benefits of VVT One benefit is an increase in maximum engine speed (and therefore more peak power) – as much as a 25% increase. Low speed torque is also increased, providing better handling and drivability.

When the VVT solenoid is malfunctioning, the entire system can be compromised, which may result in intake and exhaust valves opening and closing at the wrong time. This typically causes the fuel economy to drastically reduce.

Can You Drive with a Bad VVT Solenoid? Even though you may technically be able to continue driving with a bad VVT solenoid, the issue can cause damage to additional parts, such as the VVT actuator. So, you should address the issue as soon as possible.

5 Symptoms of a Bad Variable Valve Timing (VVT) Solenoid

1. Check Engine Light.
2. Rough Idling.
3. Rough Acceleration.
4. Increased Fuel Consumption.
5. Low engine performance.

Can You Drive It? The short answer is that, yes, you can usually drive a car with a bad shift solenoid. Fluid pressure control should continue to function in the gear with the working solenoid, but you should avoid putting any serious stress on the transmission — towing or drag racing — just in case.

Depending on the make and model of your vehicle, expect to pay between $15 – $100 for a single transmission shift solenoid. A pack can cost $50 to $300….Transmission Solenoid Replacement Cost – Parts & Labor.

Type	Cost Range
Single	$15 to $100
Pack	$50 to $300
Labor	$120 to $400
Total (Pack)	$250 to $600

To replace the solenoid in your transmission, you will pay anywhere between $150 and $400. The labor should take 2-4 hours and cost you $60-$100 per hour. The parts can be as little as $15 or as much as $100 for each solenoid.

But a faulty solenoid that fails to make adequate electrical contact inside can also produce this tell-tale sound causing the battery to have low voltage unable to provide enough power to start your engine.

As your starter solenoid goes bad, you might hear the clicking sound and the slight movement in the starter solenoid happening, but you won’t see a corresponding starter rotation, and thus, the engine won’t start. In this case, the culprit could be a broken solenoid connection due to erosion, breakage, or dirt.

Our Expert Agrees: If your starter solenoid is bad, you may hear a clicking sound when you turn the key, or your vehicle may not have any power at all. Check the battery. If your starter is failing to engage, it may be because the battery does not have sufficient energy to power it.

The starter solenoid turns an electric signal from the ignition key into a high-voltage signal that activates the starter motor. Replacing the starter solenoid with a new starter does not always have to be done. The solenoid lends itself to repair just like any other component, and savings can be realized by doing so.

Starter Replacement Cost – RepairPal Estimate. The average cost for starter replacement is between $497 and $526. Labor costs are estimated between $110 and $139 while parts are priced at $386. This range does not include taxes and fees, and does not factor in your specific vehicle or unique location.

On average, it takes about three hours to replace a solenoid. It won’t take that long for each solenoid to be replaced, but each subsequent one that needs to be replaced will add to the labor time and costs.

When you attempt to start the car, there is a low whining sound. If jump starting gets your engine started and running, but the car will not start again once you turn it off, the battery is probably the problem.

How long does the starter motor last? On average, a starter motor lasts for 100,000-150,000 miles. In many cars, the starter motor lasts for the lifetime of the vehicle; however in some cars, it can fail prematurely.

What are common bad starter symptoms?

1. Something sounds off.
2. You’ve got lights but no action.
3. Your engine won’t crank.
4. Smoke is coming from your car.
5. Oil has soaked the starter.
6. Look under the hood.
7. Tap the starter.
8. Adjust the transmission.

These are a few of the signs you may experience if the starter needs to be replaced.

1. Loud clicking. Often times the first sign of starter trouble will be a loud click or series of clicks that occurs when the key is turned.
2. Grinding noises.
3. Buzzing.
4. Intermittent engine cranking.
5. Other issues that can prevent no starts.

Jump-starting a car with a bad starter motor will not help start the engine. Jump-starting will only boost battery power. A manual transmission car with a bad starter may be push or tow started but an auto transmission car can not.