Gretsch
SILVER Star
As the world melts down with Corona Virus, it seems my Cruiser is going to get a bit of a respite from its normal daily driving duties as I am forced by management at work to stay home the rest of March. I am going to take this opportunity to not only try my best to escape contracting this illness, but to get some things done on my truck I have wanted to get knocked out while I can afford some 60 series downtime. My '84 was desmogged by the previous owner, and looking over the vacuum routing for this desmog guide, the desmog job seems to not be totally done correctly. The PO removed and ditched the HAC when doing the desmog and resorted to some vacuum routing which seems quite odd to me after going through the desmog guide. I would like to get the HAC put back in place to help with trips at altitude.
I was able to source an HAC. So working through getting it put back in place. Going through the linked guide, it seems I need to re-do the vacuum routing to get this to work correctly. The elements which are in play here are basically the vacuum ports on the carb, the primary and secondary vacuum advance ports as well as the vent on the distributor, and the ports on the HAC. To illustrate what I think I need to do here, I'll use these labeled pictures as guides for the rest of my layout:
Using the labels in the above pics, here is what I think I need to do for vacuum routing:
HAC port (a) to carb port C
HAC port (b) to carb HAC Slow Port
HAC port (c) to carb port A
HAC port (d) to "T" fitting:
o One leg of the "T" goes the distributor HAC Advance Port
o Other leg of the "T" goes to the Gas Filter via a check valve
Carb Advancer Port to distributor Vacuum Advance Port
One Vent Port to VCV for distributor ventilation port (z)
So right now, My dizzy vacuum routing looks like this:
![IMG_5338[1845].jpg](data:image/svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg' width='1440' height='1920' viewBox%3D'0 0 1440 1920'%2F%3E "IMG_5338[1845].jpg")
So Dizzy vent port to primary advance and then secondary advance port (HAC) just routes over to what looks like carb advancer port. So using secondary advance for all vacuum advance and just looping the vent to primary advance. I don't know what that routing does but does not seem like it would allow for proper timing advance under normal operating conditions. But maybe it works. Engine seems to run fine as is.
So with all that, a couple of questions and just general check me on my proposed routing. Is the desmog guide I am looking at still valid? And for this:
Other leg of the "T" goes to the Gas Filter via a check valve
I am not sure what the gas filter that's being referred to is. Charcoal canister perhaps?
Am I correct on the routing above to get my HAC back in place and working properly? I need to source VCV/VTV valves to do this properly as well I believe. My truck has none. Thanks in advance for any help here.
I was able to source an HAC. So working through getting it put back in place. Going through the linked guide, it seems I need to re-do the vacuum routing to get this to work correctly. The elements which are in play here are basically the vacuum ports on the carb, the primary and secondary vacuum advance ports as well as the vent on the distributor, and the ports on the HAC. To illustrate what I think I need to do here, I'll use these labeled pictures as guides for the rest of my layout:
Using the labels in the above pics, here is what I think I need to do for vacuum routing:
HAC port (a) to carb port C
HAC port (b) to carb HAC Slow Port
HAC port (c) to carb port A
HAC port (d) to "T" fitting:
o One leg of the "T" goes the distributor HAC Advance Port
o Other leg of the "T" goes to the Gas Filter via a check valve
Carb Advancer Port to distributor Vacuum Advance Port
One Vent Port to VCV for distributor ventilation port (z)
So right now, My dizzy vacuum routing looks like this:
So Dizzy vent port to primary advance and then secondary advance port (HAC) just routes over to what looks like carb advancer port. So using secondary advance for all vacuum advance and just looping the vent to primary advance. I don't know what that routing does but does not seem like it would allow for proper timing advance under normal operating conditions. But maybe it works. Engine seems to run fine as is.
So with all that, a couple of questions and just general check me on my proposed routing. Is the desmog guide I am looking at still valid? And for this:
Other leg of the "T" goes to the Gas Filter via a check valve
I am not sure what the gas filter that's being referred to is. Charcoal canister perhaps?
Am I correct on the routing above to get my HAC back in place and working properly? I need to source VCV/VTV valves to do this properly as well I believe. My truck has none. Thanks in advance for any help here.
