81'-86' Air Cleaners

[AuroraGirl]

Hi, I am new to this forum. I have a 1982 Chevy G20 vans with a 350. I discovered the hard way that you want an air cleaner that has a blue/grey coloured ring which appears to be a carbon filled device which is permanently sealed into the air cleaner base. I removed mine as I thought this was a restriction to air flow (which it is) I soon discovered a problem though. My gas tank began to crumple as the vacuum from the fuel pump on a sealed system was not allowed to equalize. I replaced all kinds of things including the vapour canister and still had the problem until I realized that the grey restrictor ring that was originally in the air cleaner was there to provide a small area that was not under vacuum. This was how GM/Chevy had their system set up to be compliant to hydro carbons being contained. So if your vehicle is California compliant you may want to make sure the air cleaner you look for has this intact.
Glenn

picture?

 

[JGN62]

Yes the ring would look like this and would be inside of the filter and siliconed to the actual base of the air cleaner.

 

[Craig 85]

My 85 K30 (454) came with the taller air cleaner lid. I added it to my '79 K15 (350). It's 2" taller (5" air filter). The bases are the same. I took that air diffuser out of both bases without issue. I believe the metal ring attached to the base is actually for flame retarding in case of a back fire. HD trucks have a vacuum pod on the front of the driver's side of the carb (photo 3 &

1985 - 454

You must be registered for see images attach

1979 - 350

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

4) that cracks the butterflies on deceleration at certain RPM's.

 

[JGN62]

That is interesting Craig. My vehicle came with a six port charcoal canister and is a California emission compliant vehicle. when I bought the vehicle it ran fine and the gas tank was able to equalize perfectly. I removed the ring from the air cleaner as it seemed insane to block the flow of air to the engine. But this is when I started to have the crumpling metal sound from the gas tank as the fuel would be used. There was of course also a heavy vacuum every time I opened the gas cap. I traced the vacuum/emission control lines (and confirmed on the emission label) and sure enough one goes to the air cleaner. To avoid having equalization problems in the tank, I have left the sixth port on the canister (which normally goes to the air cleaner) disconnected and only covered to protect from dust. When I did this, it totally eliminated the problem with the fuel tank. As the nicer weather comes around, I may reinstall the ring to confirm that that is the purpose of this device. On the label, you can see the sixth port line going to the canister and the fifth port line heading to the fuel tank.

 

[85K304SPD]

1985 K30. Regular leaded gas. I dont think that it has a charcoal cannister.

 

[Craig 85]

1985 K30. Regular leaded gas. I dont think that it has a charcoal cannister.

I’m pretty sure it did. I think the main difference, at least with 454s is California had an EGR where the Federal trucks did not.

I know my ‘77 K5 had HD emissions with an SBC 400 , smog pump and charcoal canister. I can’t remember if it had an EGR. It ran on Regular.

@VPC20HD here's my diagram. It's the factory one on my air cleaner base. Although it's for a 454, the color routing may help you.

You must be registered for see images attach

 

[AuroraGirl]

I’m pretty sure it did. I think the main difference, at least with 454s is California had an EGR where the Federal trucks did not.

I know my ‘77 K5 had HD emissions with an SBC 400 , smog pump and charcoal canister. I can’t remember if it had an EGR. It ran on Regular.

@VPC20HD here's my diagram. It's the factory one on my air cleaner base. Although it's for a 454, the color routing may help you.

You must be registered for see images attach

here is what your air cleaner would have said
EXCEPT it would say 1977*