Correct Installation of VVT Actuator Piston
 

Hey everyone, I have found some conflicting information that may be due to model year changes.

Just for clarification, I refer to the VVT parts as follows, in assembly:

Cam gear
Lower housing
Rotor housing
Rotor
Actuator cover

Makes sense? Cool. If not let me know.

In this thread: https://www.miataturbo.net/engine-pe...or-pics-80407/

The gentleman removes the "locking pin" from the lower housing, leaving a spring behind, as shown in the photo below.

https://cimg2.ibsrv.net/gimg/www.mia...40ce21f7ce.jpg


This suggests that the "locking pin" moves downward when oil pressure is applied to the top of it, and the spring pushes it upward when there is both insufficient oil pressure to keep it pushed down and when the rotor moves into the fully retarded position.

However, in this thread: https://forum.miata.net/vb/showthread.php?t=448035

The gentleman removes the locking pin from the rotor instead of the lower housing.

https://cimg1.ibsrv.net/gimg/www.mia...b9b5cee456.jpg

This suggests that THIS design is intended to push upward into the rotor and allow movement of the rotor to advance the timing. When the rotor returns to it's fully retarded position, the locking pin is pushed downward into place in the lower housing. Also this suggests that there must be some oil pressure that moves through the lower housing, otherwise there would be no way for the locking pin to push upward.

Here's where I'm getting confused:

It would appear that in my 2002 Miata, I have the second setup shown, which suggests that the latter setup was used in later model Miatas. I am not certain if either installation is correct for me. It looks like the landing in the lower housing is far too shallow to allow for inward motion, which means that the locking pin must move upward into the rotor housing, correct? Does this mean that oil pressure moves through the lower housing?

Please let me know if I have this correct, as my car is back together and it idles like total trash and I can't figure out if I had installed this piston backwards into my VVT actuator. I've searched around but there doesn't seem to be any clarification on this subject.

bump, i'm taking apart my actuator again to clean it out after a spun bearing and I want to be sure i'm putting this in right. Nobody replied previously.

Hey, I've just been working on this on my 2003 Miata. I took the actuator apart while doing a timing belt/water pump change because I stripped one of those torx screws and couldn't get where I needed to otherwise. VVT actuator thingie fell apart, but I gathered all the pieces. I have seen both posts you mention, and I think it may depend on model. The pin looks like the bottom one on mine (one stripe), and the only way that the actuator could even possibly rotate is if I have the spring in the rotor and pin on top of it. Otherwise there is not enough clearance in the bottom housing to fit the whole pin. I'm guessing the bottom vane in that rotor will pool oil under high pressure in the pin hole, push the pin up, and allow the VVT to move forward, and it would then move back and lock in place at low oil pressure. So I'm fairly confident about it, but I have not put the car together yet to test it out. I hope I am right because I would really like to avoid getting a new VVT actuator. By any chance, do you know the correct orientation for the little puck? Is it label facing up (deeper portion facing down)? Does it matter?