How does the Variator Solenoid Control Valves work?

They're basically a tube within a tube where the inner tube is connected to the crankshaft, and the outer tube is connected to the timing gear. The outer tube has holes drilled into it in which oil CAN flow. The assembly turns with each turn of the timing belt. The outer tube is sealed with rubber seals before and after the holes drilled into it.

There is an oil channel in the block that leads to the pressurized oil lubrication system of the engine. No oil flow goes into this oil channel unless the Variator Solenoid gets an electrical voltage that causes the electromagnet in its center to move upward, opening the channel (above 3600 RPM IIRC?). The oil then is allowed to flow in the channel. This oil flows through the channel/tube/passageway into one side of the variator, through the holes drilled in the outer tube. This "pressurizes" the space between the inner and tubes of the variator. When this happens a mechanical mechanism "rotates" the outer tube relative to the inner tube a few degrees. This is what changes the timing. When the solenoid valve closes, the oil pressure drops and the oil doesn't flow through the variator, and the timing goes back to normal.

The solenoid control valve is literally a solenoid consisting of an outer winding of wire, that when charged, causes an inner plunger to move up and down subsequently opening the channel between the holes in the variator solenoid so oil can flow. That simple. When the windings in the solenoid get older, the resistance can build or the plunger can get sticky with oil residue and not move as fast or efficiently leading to a code.

 

When that works, does it just go fully from one position to the other ? or does it go say to a mid position ?

 

On or off.

 

Ta, i was thinking that was the case- otherwise you would need some sort of sensor to tell you where it was.
Out of interest how many degree of cam timing does it move.

 

They aren't on or off but would behave as such if one applied 12v to the contacts. They are in fact a proportional flow type valve modulated by a PWM signal in order to regulate the degree of camshaft advance.

I'm very busy at the moment but soon I'll write up some info on their operation and testing - keep an eye on my project thread.

 

On a Ferrari 360? This will be an interesting dissertation.

 

OP owns an F430.

 

I am guilty of an assumption but some specificity in the question would be great.

 

If you have access to the plug for the solenoid on the top of the engine I'd check the resistance on the plug. Confirm that they are al equal. That *might* suggest that the plunger is sticking on the solenoid. I haven't priced it out as I have a 360 and the solenoids are outside the engine vs/ the 430 being under the valve covers... but perhaps if the error keeps popping up you might consider removing the variator solenoid and put it into an ultrasonic cleaner. Rationale being if there is some crud in it the cleaner might get it out. Not sure what price of this might be vs. replacing with new... .

 

Hi Dan,
Could you get a reading that showed which one was defect? Did you end up cleaning them or changing?