CRG Discussion Forum
Camaro Research Group Discussion => Originality => Topic started by: ccargo on November 24, 2008, 06:39:46 PM
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I've run out of vacum ports on the 68 L78 4053 to hook up the signal hose to the diverter valve. The A.I.R system is inactive but I need somewhere to run the hose?
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Tee into the choke pull-off hose with the take-off to the diverter valve plugged with something (since the A.I.R. system is not functional). Did you remove the vanes inside the pump?
Steve
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Yes, its devaned :) Is it anything special that should be used? I have some T's left over from the RS setup. I think I saw one that was run all the way back to the intake manifold vacum T"s but I cant find the photo? Most of the ports off the manifold are to large anyway. Another question. Where do you guys get belts? I doubt they make an aftermarket for this application and from experience they wouldnt take the RPM's anyway.
Thanks for the response!
Pat
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Nothing special. Just a plastic one will do. I would probably plug the port going to the diverter valve with some good quality silicone sealant. The choke pull-off hose is a common connection for the diverter valve hose tee. As for the belt.....my system is original and functional and I have always replaced it with the run of the mill auto parts belt. Try Advance Auto Parts....they have some listed (AP = Air Pump) for cars with and w/o A/C.
Steve
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I recently gutted my smog pump and plug the diverter valve hose with a 1/4" - 3/8" cut length from a plastic gulf tee. It worked great.
On my 69Z, my vacuum advance line is now connected to full manifold vacuum, at the "T-fitting" at the base of the carb where the diverter valve hose was originally connected. To find a place to put the diverter vacuum line, I plugged it into the "ported" source on the base of the carb. The modification is all hidden under the cowl induction air cleaner, and easy swapped back for a car show if needed.
I am not sure if this will help your set-up but the attached picture will give you the basic idea.
Good luck with you modification.
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I see what you've done and it makes sense. I've still not found a T fitting for the vacum at carb and it makes me a little nervous to split that port when its feeding the advance. I'd still like to see a photo of an original setup. Thanks for sharing :)
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Photo below of the original factory setup - note the tee in the choke pull-off diaphragm hose for the diverter valve signal hose, and the "ported" vacuum advance connection to the carb baseplate.
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Do you need to make any adjustments to timing or idle when the vacum lines are run this way ?
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No special timing or idle adjustments are needed. You can readjust them both back to spec; however, I would recommend that you bump up or advance your initial timing (from spec) about 8 - 12 deg BTDC depending on your engine "likes", without pinging under a load. There are a number of good discussion topics on CRG covering timing.
Good luck with your project.