A.I.R on 4053 Holley

[ccargo]

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?

[Steve68]

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

[ccargo]

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

[Steve68]

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

[Dave69x33]

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.

[ccargo]

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 

[JohnZ]

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.

[fireZ]

Do you need to make any adjustments to timing or idle when the vacum lines are run this way ?

[Dave69x33]

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.