Best Practices using Cam Angle Test?

[defjux23]

What's the best way to utilize the Cam Angle Test to set the Offset... or better yet, what's the best procedure for setting up VVT in general? Can activating the test while the engine is running cause the solenoid to advance the cam? While preparing our engine for the dyno we turned on the Cam Angle Test and noticed an awkward sound and our intake valves touched the pistons. We noticed the same sound when using the set base trigger offset as well. VVT tables were all zeroed.

[defjux23]

To be a bit more specific. When turning on/off the Cam Angle Test and opening up/closing the Base Trigger Offset window, does the VVT solenoid get activated in a way that could advance the cam timing?

 

Thanks in advance!

[Adamw]

The solenoid is disabled when the cam angle test is enabled, so the cam should return to is home position during the test.  

[QE1984]

If the VVT tables were at zero, should there be any change at all? 

[defjux23]

25 minutes ago, Adamw said:

The solenoid is disabled when the cam angle test is enabled, so the cam should return to is home position during the test.  

When vvt is enabled after the test is done, would the activation of the solenoid possible cause the cam to fully advance?

[Adamw]

40 minutes ago, defjux23 said:

would the activation of the solenoid possible cause the cam to fully advance

If you had advance commanded in your target table and all the lockout conditions where met then yes it will go to whatever target you are commanding. 

 

43 minutes ago, QE1984 said:

If the VVT tables were at zero, should there be any change at all? 

If the offsets arent set how does the ecu know where zero is?  "zero" may be 10 deg advanced if your offsets were out by 10deg.  

[QE1984]

I see. But if the table is set to zero, after doing a proper cam angle test, the cam should not advance at all once the test is done, correct?

[defjux23]

14 hours ago, Adamw said:

If you had advance commanded in your target table and all the lockout conditions where met then yes it will go to whatever target you are commanding. 

 

If the offsets arent set how does the ecu know where zero is?  "zero" may be 10 deg advanced if your offsets were out by 10deg.  

Would you have an order of operation to be as safe as possible to not cause any over advance?

I assume it would be 1) Turn off VVT. 2) Set Base Offset. 3) Shut off Engine. 4) Enable Cam Test. 5) Start Engine and find cam offset. 6) Set cam offset value. 7) Shut engine off. 8) Enable VVT. 9) Start engine and we should be complete.

Correct?

Any other words of advice?

[Adamw]

What are you worried about?  There are mechanical stops so the cam cant over advance, the cam should be able to move from fully retarded to fully advanced at any time.  

Generally you would start the engine, turn on the cam angle test, set the offset, then tune the control if required.    

[defjux23]

52 minutes ago, Adamw said:

What are you worried about?  There are mechanical stops so the cam cant over advance, the cam should be able to move from fully retarded to fully advanced at any time.  

Generally you would start the engine, turn on the cam angle test, set the offset, then tune the control if required.    

I'm concerned about two things, obviously it's possible with our setup to over-advance. We are looking into a mechanical solution to stop that. Second, damage to the phaser when turning on/off the test and opening the base offset window. Perhaps we've wired something wrong on our end, but something in the solenoid/phaser area made a very strange noise while turning on and/or off the tests. Maybe it was just the valves contacting the pistons. Unfortunately we can't be quite certain.

[Adamw]

You should not run an engine if valve contact can occur anywhere in the VVT range of motion.  The are many conditions under which the VVT could move more than commanded such as when tuning the PID or when oil is cold.  It needs to be mechanically limited to a max position where contact cant occur.  You need to leave VVT disabled until you can fix that.  The phaser generally doesnt make any noise at all so the noise you heard is likely piston to valve contact.  

[defjux23]

14 hours ago, Adamw said:

You should not run an engine if valve contact can occur anywhere in the VVT range of motion.  The are many conditions under which the VVT could move more than commanded such as when tuning the PID or when oil is cold.  It needs to be mechanically limited to a max position where contact cant occur.  You need to leave VVT disabled until you can fix that.  The phaser generally doesnt make any noise at all so the noise you heard is likely piston to valve contact.  

Thanks for the additional information.