If your engine oil has not been changed out on schedule, it could damage the VVT solenoid, the VVT chain, and the gear drive. To avoid this situation, make sure to have your engine oil changed as recommended by the vehicle manufacture. Low oil levels can also cause problems with the VVT solenoid and other timing system components.
Typically the VVT system does not activate until the engine is at higher RPM or is introduced to load bearing situations like driving uphill. However, if the VVT solenoid is malfunctioning, it is possible that it will introduce additional engine oil to the VVT gears. This can cause the engine to idle rough , specifically the engine RPM to fluctuate as the system is activated. If not checked quickly, it can cause additional engine components to wear prematurely.
If your engine idle is rough , make sure to have a certified mechanic inspect this as soon as possible. The purpose of variable valve timing is to ensure that the valves open and close at the right time to maximize engine performance and reduce fuel consumption. 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.
If you recognize any of the above warning signs of a bad or failing variable valve timing solenoid, contact a local ASE certified mechanic from YourMechanic. They can inspect your vehicle, replace the variable valve timing solenoid if needed, and keep your car or truck running strong. This article originally appeared on YourMechanic. Autoblog is partnering with YourMechanic to bring many of the repair and maintenance services you need right to you.
Get service at your home or office 7 days a week with fair and transparent pricing. We get it. Ads can be annoying. This is an idea whose time has come, but like most innovations, it has been slow to be accepted by the performance industry. Before we get into exactly how VVT works, we thought we should explain why VVT is such a good idea for a number of excellent reasons.
Variable valve timing offers some wonderful opportunities for the engine designer and builder. While all four are essential, the most important valve event of the four is IC.
If all we had to do was make power within a very narrow 1,rpm band—as with a five-speed manual trans drag race combination or a cabin cruiser boat engine that operates 98 percent of the time at a set cruising rpm—then moving the camshaft around is of limited benefit.
But street engines are expected to deliver excellent power and throttle manners between idle and 7, rpm. This is where VVT really shines. VVT is all about advancing or retarding the camshaft. To make this simple, we can discuss this using the intake centerline as our reference point. Advancing or retarding the camshaft means that we will be moving the intake closing point in relation to the piston.
Advancing the centerline will shift all the valve events to open and close earlier. Specifically, advancing the cam four degrees means the intake closing point will now occur four degrees earlier than its original position. In a general sense, advancing the cam tends to improve low-speed torque while retarding the cam will improve high-speed power.
For street engines with a fixed timing position, the engine builder is forced to choose a compromise position mostly based on how the engine would be driven. If the engine was predominantly street driven, this generally meant the cam would be advanced. The CMP actuator cannot vary the duration of valve opening or valve lift. The CMP actuator is to be serviced as an assembly. Do not push or pull on the reluctor wheel of the CMP actuator during removal or installation.
The reluctor wheel is retained to the front of the CMP actuator by three roll pins. Pushing or pulling on the wheel may dislodge the wheel from the front of the actuator. The actuator return spring is under tension and may rotate the dislodged reluctor wheel, causing personal injury. A CMP actuator dynamically changes valve timing events relative to piston timing by controlling camshaft position.
This is sometimes referred to as variable valve timing or camshaft phasing. Advertisement There are five cavities divided by vanes within the CMP actuator. When oil is directed to the advance cavities, the camshaft timing is advanced.
When oil is directed to the retard cavities, the camshaft timing is retarded. When oil is directed to both cavities, the camshaft is held stationary. The CMP actuator has a 52 degree range of movement at the camshaft later models have 62 degree range of movement. With the engine not running and no engine oil pressure to the CMP actuator, the high-tension spring positions camshaft timing at the 7 degree advanced park position at the crankshaft 3.
During normal engine operation, and based on performance requirements, the ECM may adjust camshaft timing as required within a range from 7 degrees advanced at the crankshaft 3. The valve may also, under certain conditions, be positioned in a neutral position with alternating low, balanced oil flow between the advance and retard passages of the actuator. Advertisement Oil flows from the camshaft into the valve inlet 3 through the internal check ball and filter.
Oil exits the valve 2 and travels within the internal passages of the camshaft into the entry ports 7 of the actuator. Dubbed the L99 SS, Mast's combo features a 6. Mast conservatively rates the at hp. To test the virtues of the VVT system, we made several pulls on Mast's SuperFlow dyno with the cam phased in three different positions: advanced for maximum torque, retarded for maximum horsepower, and with the VVT system engaged.
The results were quite impressive to say the least. The L99 produced maximum torque with the cam advanced 5 degrees. In this configuration, the motor put out hp at 6, rpm and lb-ft at 5, rpm. When it came time to maximize peak hp, the responded best to 4 degrees of retard. This arrangement yielded a peak output of hp at 6, rpm and lb-ft at 5, rpm.
The results are precisely what would be expected, with the L99 making 10 lb-ft more at fewer rpm with the cam advanced and 18 additional horsepower at rpm higher in the powerband with the cam retarded. In a standard non-VVT motor, this would typically be the point where you'd have to decide to sacrifice low-end for top-end, top-end for low-end, or shoot for a happy medium between the two. In theory, this is the sort of compromise VVT promises to eliminate, and on Mast's dyno, it did just that.
With the VVT system switched on, the L99 cranked out hp at 6, rpm and lb-ft at 5, rpm. These dyno runs prove that the results live up to the hype, and VVT is quite literally the best of both worlds. Engaging the VVT system yielded horsepower and torque output that was spot on to the prior tests in which the cam was retarded for max power and advanced for max torque.
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