Author Topic: 7040564  (Read 474 times)

Offline 4ever18

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7040564
« on: June 24, 2019, 04:27:48 AM »
I bought this 7040564 Pontiac Q-Jet (California emissions Firebird 400) and I’m beginning the restoration process.  It's in really good shape but this is the first time I've run across this type of bowl vent.  At first I thought it was a remanufactured unit but realized that it was to comply with CA emissions laws at the time.  Some very unique parts that I doubt are available any longer.  The question that I have is that the 3 bee-hive shaped return springs were stacked on top of each other.  I'd assume that one spring would work but thought I'd bounce it off the experts in the group.  It also appears that someone didn't like the length of the stack on the bowl vent cover and shortened it.  No big deal as I have replacements.  I'll just need to drill a hole for the vent switch.  Sooooo, any idea if I should restack 3 springs or use just one?
Thanks,

Online Cliff Ruggles

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Re: 7040564
« Reply #1 on: June 26, 2019, 03:37:20 AM »
Why use the vent switch and vapor line to the charcoal canister at all?  If you want correct appearing leave it all in place and disable it.

Just install a new cover that isn't chopped off, drill a hole in it, hook up all the parts but disable everything including the vacuum supply. 

That vent is not needed and only used one year with that type of carb.  I've built quite a few of those and leave all the components in place but block the large 3/8" vent tube internally and just set them up so it looks correct but non-functional.

The only purpose anyhow was to vent vapors to the charcoal canister.  It has PLENTY of venting area already so it's not needed.......Cliff

Offline 4ever18

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Re: 7040564
« Reply #2 on: June 26, 2019, 03:53:25 AM »
Thanks Cliff.  But can you tell me if only one spring is used?  I was puzzled to find three of them stacked together when I disassembled.

Online Cliff Ruggles

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Re: 7040564
« Reply #3 on: June 27, 2019, 03:12:04 AM »
Can't remember seeing one with multiple springs, but it's been a while since I've done one.  They are pretty rare, one year only and CA emissions only......