KNIGHTE

Hey Guys,

As you may have read from previous thread - i need some AIR stuff for my 85 Trans Am. Its an LG4

I'm not a mechanic so i'm not entirely sure what exactly i am missing!

I'd like to try and source the parts so that i can give them all to my mechanic rather than wait weeks for him to find them in a junk yard!

The thing is - i don't know what i am missing from a visual

Here is what i know i need
=================
Smog Pump
Misc Hoses
Possibly the Original Air cleaner?

Worries
=================
My Cover does not have a PVR valve(?!)

I don't know what the exact parts are. I've looked at broken out diagrams but there are so many parts... i just don't know which are which.

If someone could help me piece it together i would really appreciate it.

Engine pics below! I'll be adding more if anyone needs them.

https://www.flickr.com/photos/113572...7651948231432/

mcquigg

From the photos that you provided and assuming the CAT is still there all you need is the AIR pump, the diverter valve, a check valve for the passenger side, and some hose. If I remember correctly it's something like 3/4" hose that you can use to replace all of these connections. I do have the original 85 AIR pump from my car when I installed the serpentine system if your interested, it's in good working condition. I don't have the diverter valve to put with it but they are a little easier to acquire used. If you search the forum you can find some good pictures of the smog equipment.

jeff1986z

I agree that you will probably need an original air cleaner assembly. There should be a breather tube that runs from the valve cover (in place of the breather cap) to the air cleaner.

KNIGHTE

Hey Jeff - Do you mean the tube hanging in this pic?

https://www.flickr.com/photos/113572...57651948231432

KNIGHTE

Hey Dude, thanks for your help.

I *think* i've found the breakout diagram for the LG4

If you had a minute, would you be able to let me know which numbers i need? That would help me a ton.

http://parts.royaloakschevy.com/show...1026mf3-4mf3-4

*UPDATE* - Dang - Diverter valves are expensive new!

jeff1986z

No, but that is your pre-heater hose, which also connects to the air cleaner. The breather hose will run from the other valve cover to the side of the air cleaner. In addition, you should have a PCV valve in the driver side valve cover that runs to either the intake or carb (check the vacuum diagram).

What might be beneficial is to search for an image of any typical GM passenger car of that era with a carb'ed 305. At least that way you can take note of what's missing, make a list, and head for the junkyard.

Hope that helps!

KNIGHTE

Hey Jeff,

My covers don't have PCV valves, does that mean I need to replace them aswell?

paulo57509

You'll need pretty much all the parts in the attached drawings for the AIR system.

paulo57509

Here's the parts for the PCV system.

One thing to keep in mind: GM may have made some year-to-year and/or mid-year changes so these pages from the assembly manual might not depict exactly what your car came with from the factory. However, it does represent the parts needed for a fully functioning system (both AIR and PCV).

Also, the GM part numbers listed have most likely changed as well.

mcquigg

Oh yeah, smog parts are just because the demand for them is low. You can get diverter valves on ebay for less than $30 typically. Pumps tend to run a little over $100 for a rebuild. Good used pumps are difficult to find just because most people will run them until they seize then just remove the belt and never give it another thought.

About the only items that you will get new/rebuilt will be the pump, diverter, and check valve, maybe some of the hoses. The rest of the parts you have to source from a junk yard, you will probably have to piece together the parts from several cars since it may be difficult to find a car with all the components intact/functional

jeff1986z

Possibly... I'm sure you could get grommets to fit your existing valve covers that have the proper size opening for the breather tube and PCV valve. What I don't know is how strict they will be at a visual inspection, and whether aftermarket valve covers are allowed. Maybe someone else can chime in who has experience with visual inspections.

KNIGHTE

Hey Paulo,

Thanks for these diagrams buddy, these are EXTREMELY helpful.

Are these from an assembly manual? Where did you get them?

paulo57509

You're more than welcome.

Yes, those pages are from a 1986 Camaro Assembly Manual. I bought the manual (which was a loose leaf copy) off an ebay seller. I brought the manual to work and scanned it into a .pdf file.

I see them for sale on ebay all the time.

I hope the DMV registration process goes well.

KNIGHTE

Thanks Dude - I just dropped off ALL of the smog components (which i pulled from an 82 trans am) including the stock Valve covers to my mechanic. Lets hope he can put it all back together :-) I gave him your print outs and some others.