Author Topic: 68 396 L34 Q-jet vacuum to AIR valve  (Read 6564 times)

My68SS

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68 396 L34 Q-jet vacuum to AIR valve
« on: December 06, 2010, 11:56:47 AM »
Hi all,
It's hard to tell looking at the 68 AIM, but it appears that the long vacuum pipe on the RH side of the carby, behind the choke pull-off, is the connection point for the AIR valve vacuum, as per below pic [not my pic/carby - wish it was!!  :)]
Can someone confirm for me?

If so, then this would have been rubber capped off for non-AIR vehicles?
TIA
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

bertfam

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #1 on: December 06, 2010, 05:59:02 PM »
I believe (and John will correct me if I'm wrong), that any CCS carb (non-A.I.R.) wouldn't even have that vacuum fitting. However, since all big blocks in 1968 came with A.I.R., the correct carb for your L34/M40 (7028218-EH) would have that fitting and it would have been used.

Ed

Boston14

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #2 on: December 07, 2010, 12:04:42 AM »
On my 1969 L48 Automatic (M38) car, carb number 7029202 DH, there is no A.I.R. system, the Therm ac system in the air cleaner uses this port.  1969 L48 standard transmissions have no Therm ac system but they do have A.I R. that uses that port.   I am not sure about 1968s'.

boston14
boston14

1969 SS/RS 350 Convertible
Dover White with Black Top and D90 stripe, Red Standard Interior

My68SS

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #3 on: December 07, 2010, 12:23:46 AM »
Hi Ed/Boston,
Yes, as Boston14 notes, it's my understanding that autos were not fitted with AIR.
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

bertfam

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #4 on: December 07, 2010, 12:38:03 AM »
Quote
Yes, as Boston14 notes, it's my understanding that autos were not fitted with AIR.

No, as per the 1967-1969 Camaro Emission Systems report:

Quote
In 1968 and 1969, the California and federal emissions requirements were the same and all cars were built to the same 50-state standard. The AIR system was installed on all L6 cars with manual transmissions, all small blocks with manual transmissions, and all Camaros with big blocks. (Chevelles and full-size cars with the 396/325hp engine and TH400 transmission were the only 68-69 Chevrolet big block cars that did not have smog pumps.) Only the automatic L6 and automatic small block Camaros did not have smog pumps, instead they had the simpler Controlled Combustion System. Generally speaking, an automatic car required less aggressive emission control than a manual transmission car because the engine load (and carburetor fuel metering consistency) was more stable and predictable.

Thus, the only engines NOT equipped with A.I.R. were the L6 with automatic transmission, and small blocks with automatic transmission. All other Camaros received the A.I.R. system. Boston14 has the 350 with automatic, so he had the CCS system.

Ed

Boston14

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #5 on: December 07, 2010, 04:34:19 AM »
Yes, my L48 has the thermostatically controlled air cleaner, but my point was that all 1969 L48 engines have the vacuum port in question and that it is used, with or without A.I.R.
boston14

1969 SS/RS 350 Convertible
Dover White with Black Top and D90 stripe, Red Standard Interior

bertfam

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #6 on: December 07, 2010, 04:42:46 AM »
Quote
Yes, my L48 has the thermostatically controlled air cleaner, but my point was that all 1969 L48 engines have the vacuum port in question and that it is used, with or without A.I.R.

Ah, I see what you're saying. Thanks for that info.

Ed

My68SS

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #7 on: December 07, 2010, 05:14:54 PM »
Thanks Ed/Boston14,
Mine would have been shipped without AIR [export to Au] so would have been capped off, which is probably what they did with Canadian and other country exports ?
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

bertfam

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #8 on: December 07, 2010, 05:40:20 PM »
Quote
Mine would have been shipped without AIR [export to Au] so would have been capped off, which is probably what they did with Canadian and other country exports ?

Correct. Option KD1 was used to delete the system, so caps would have been used. If you look in the AIM, it shows a couple of ports and vacuum lines that were capped off. It doesn't appear to show that particular port, but it does show P/N "3928101 Cap" for other lines.

Ed

My68SS

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #9 on: December 17, 2010, 02:17:13 PM »
Yes, L30 A3 of the AIM clearly shows the smog valve vacuum connecting to that carby port.
L35 A7 shows the same thing, though not quite so clearly.
Veiw 'A' of KD1 A1 is not clear at all, almost looks like a 'T' fitting that's being capped off  :-\

btw Ed, how did you construct that href link to the emissions pdf ?
Hovering on the Insert Hyperlink icon doesn't reveal the syntax anymore, or am I thinking of another site ??
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

bertfam

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #10 on: December 17, 2010, 03:02:17 PM »
Rob, I don't think hovering over the link will show you anything. At least it doesn't for me, and I don't remember it ever doing that.

You can add URL links, pictures, modify text... all kinds of stuff by using BBcodes, which are modified versions of HTML code. However, instead of using the < and the > symbols, they use the [ and the ] symbols.

Click HERE to learn how to add different kinds of links.

Note that not all web site forums allow BBCodes so they may not work. We do, as does the Team Camaro site, so have fun!!

Ed

My68SS

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #11 on: December 17, 2010, 03:56:53 PM »
Ah that's right, that's the format I remember. It must have been another site that had those syntax's included in the hover pop-up description.
Cheers.
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

Jerry@CHP

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Re: 68 396 L34 Q-jet vacuum to AIR valve
« Reply #12 on: December 18, 2010, 01:33:45 AM »
I have the 1968 GM AIR chart in my 67-68 Camaro book.  All big blocks did come with smog. 

Jerry