Under plenum pics of a '90 just for reference

[WydGlydJim]

Thought someone might be able to use these. And what it should look like when you are finished!
:mrgreen:

http://members.cox.net/wydglydjim/newpowdercoat2.jpg


http://members.cox.net/wydglydjim/DSC00040.JPG

http://members.cox.net/wydglydjim/Picture%20005.jpg

http://members.cox.net/wydglydjim/Picture%20004.jpg

[billybaloneey]

The one section pictured...before and after...cleaned up nicely...good job.

[XfireZ51]

It might be the angle on the pics,
but those secondary vacuum canisters look like
they need to be flipped around. The lever looks
like it's should be on the other side closer to actuator lever.

[WydGlydJim]

It might be the angle on the pics,
but those secondary vacuum canisters look like
they need to be flipped around. The lever looks
like it's should be on the other side closer to actuator lever.

As far as I know, the plenum had never been off, but i can't say that for any real certainty, just going by what it looked like when pulled, and I did not pull the actuators. However your question led me to do some digging around. They are at a kind of wierd angle, but I did check operation, and it was fine, and I found this pic, that shows roughly the same strange angle. They are not in line with the butterfly actuators, but rather at an angle. Course the angle is a little more drastic on my pc, maybe it is on backwards heck I don't know.....Wierd:icon_scra

http://www.pnwzr1.net/Registry%20project%202/20.JPG

[jonszr1]

the angle on both my zs are the same . and they operate fine , but it allmost look that if they were turned around they would hit ? does anyone know for sure or have pics showing what they should look like .?could they have been installed wrong at the factory

[Dandy97]

The first time I removed the plenum I found mine were like the ones shown. This is supposedly flipped. I flipped mine around and checked them with a vacuum pump and they no longer actuated properly. I reinstalled them incorrectly and they tested out fine, so I left them. I think if they have been backwards for a long time they should be just left alone.

[XfireZ51]

When I first pulled my plenum, I found mine in the same shape as your original pic. I flipped mine around. They were fine. Someone like Jeffvette or Pete ZR-1 could chime in but I recall reading another thread sometime ago on the orientation of the canisters.

[Jeffvette]

When I first pulled my plenum, I found mine in the same shape as your original pic. I flipped mine around. They were fine. Someone like Jeffvette or Pete ZR-1 could chime in but I recall reading another thread sometime ago on the orientation of the canisters.


The issue I believe was initially reported by Gordon K I believe. The issue is the actuators are installed upside down or 180 degrees. The arm is not in a correct line to be drawn back into the canister. The problem is, after being installed in that position for 18 years, that the rubber diaphragm has been reformed to the incorrect position. If you mount it correctly using an original actuator, you run the risk of severe binding and not being able to open.

Only when you are replacing with a brand new actuator, should you install it in the correct position.

[detch]

here is a pic of my 95, looks the same

[Jagdpanzer]

Only when you are replacing with a brand new actuator, should you install it in the correct position.

Are these secondary vacuum actuators still available and where is a good place to buy them reasonably?

[A26B]

The first time I removed the plenum I found mine were like the ones shown. This is supposedly flipped. I flipped mine around and checked them with a vacuum pump and they no longer actuated properly. I reinstalled them incorrectly and they tested out fine, so I left them. I think if they have been backwards for a long time they should be just left alone.

:thumbsup:I had the same experience and also believe they should be left as-is and not flipped around.

[WydGlydJim]

When I checked mine, I did notice there was some very minor binding while operating, so I made that better by actually bending the bracket a little........interesting subject; once again the knowledge here is awesome. If and when I go back down under, I may change to new ones.......question is still out there...availability?
:happy1:

[tomtom72]

The old P/N used to be 1996743. I get that from my parts CD that I got from Limey when (4+yrs ago) I just bought my Z. I ran the number at GMPartsDirect, P & G, Samuels Chevy and come up with "no parts found".

Now there was a time when even if you plugged in and out of date P/N, you would get the new P/N. Soooo, I can't say if the actuators are NLA, or if the old P/N is superceeded and the system doesn't give the newer P/N...sorry!
:redface:

The only thing I could think to do would be to call Tom Henry Chevy????

:o
Tom

[A26B]

When they were last available, the quality control was very poor. About 75% were defective, so be cautious & vacuum check operation before buying...... if you find any.

With all the secondary removal mods going on, there may be good used ones about.