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