to vent or not to vent.... [Archive] - Chevelle Tech

: to vent or not to vent....


70 SS 454
Dec 27th, 99, 2:17 PM
so whats the deal with all this shakespeare lately...

anyway on to more improtant topics..my fuel cap always vents ALOT of pressure when i release it therefore i assume it is non vented..and i assumed that was the correct cap...what is the correct cap???

is this why my carb is constantly "oozing " raw fuel into the bores??...seems tobe coming from the gaskets between the carb body and the venturi cluster assembly even tho the screws are tight..

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Rich
Cocoa Beach, Fla
Team Chevelle #380
wa3men@aol.com
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vendo396
Dec 27th, 99, 5:14 PM
I have a note posted also...my tank builds up pressure too, got the cap from auto parts store my other line from the tank is open.

<BLOCKQUOTE>quote:</font><HR>Originally posted by 70 SS 454:
so whats the deal with all this shakespeare lately...

anyway on to more improtant topics..my fuel cap always vents ALOT of pressure when i release it therefore i assume it is non vented..and i assumed that was the correct cap...what is the correct cap???

is this why my carb is constantly "oozing " raw fuel into the bores??...seems tobe coming from the gaskets between the carb body and the venturi cluster assembly even tho the screws are tight..
<HR></BLOCKQUOTE>

chev64
Dec 27th, 99, 5:38 PM
The stant part # is 10646 for 49 state emmissions and # 10806 for California cars. The catolog doesn't say wether it is vented or not.

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Leo Paugh
Maryland Chevelle Club #017
Those who do the world's real work don't usually wear ties.

260
Dec 27th, 99, 10:18 PM
Rich,
If you have an original CA car then it would have a non-vented gas cap along with the NA9 carbon canistor.If you don't have the NA9 set up then I would go for an original vented style cap.

Gene Chas
Dec 28th, 99, 6:30 AM
Rich, I haven't had personal experience with it, but when I had my "no vent" post up a while back fellas were saying that using the vented cap in non vented situations might cause raw fuel escaping through the cap on hard acceleration.

For my 67 the cap was non-vented and they had, I believe a still-looking set of tubes that the vent line plugged into. Anyway, I simply use a fuel line with a screen on the end for my vent. It works mint, I no longer smell gas in the cabin and since, I have to fill up ALLOT, I've never had any pressure in the tank as I released the cap.

On some older cars, it would be easy to imagine these vent lines getting plugged up with debris.

70 SS 454
Dec 28th, 99, 9:02 AM
where do these vent lines connect to the tank..do i have to drop the tank to see them?
does the vent normally extend up into the trunk area on the passenger side?? i seem to remember a curvy line/loop in thr trunk of my dad's 69 impala years ago that i never knew what it was

i see 2 lines both going to fuel pump...one larger than the other probably 3/8 and 1/4...no canister just a single line from the pump to the carb so 3 pump lines total...

so it looks to me like there is no vent at all!

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Rich
Cocoa Beach, Fla
Team Chevelle #380
wa3men@aol.com
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[This message has been edited by 70 SS 454 (edited 12-28-1999).]

chev64
Dec 28th, 99, 10:29 AM
70SS454, That small line is/was a fuel return line,you probably don't have an original type fuel pump on your car. The return line was to help prevent vapor lock by returning some of the fuel to the tank. There was a lot of underhood heat that would cause the fuel to percolate(boil) and cause running problems.

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Leo Paugh
Maryland Chevelle Club #017
Those who do the world's real work don't usually wear ties.

chev-hell
Dec 28th, 99, 3:49 PM
cool i smell gas in my cabin a lot and think this may be my problem since i don't have a vented cap and i have a lot of pressure at fill up think this is th problem?

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John Krenn
1970 malibu SS look-a-like well kinda
307/200-4r (soon to be 355)

Ft.Worth, Tx