79 SA rats nest delete
10-30-16, 11:55 AM
#1
Junior Member
Thread Starter
79 SA rats nest delete
I have been looking around for a diagram to delete the emissions rats nest. The sticky in this forum is not available it says. The few I have found show a small vacuum line on the oil filler neck, but mine does not have that. Can anyone point me in the right direction or have a diagram I can have?
10-31-16, 03:33 AM
#2
See if this Thread helps:
https://www.rx7club.com/1st-generati...oblems-422554/
I see your issue with dead-links to Forum articles. Several I have are now dead too. Shame!
Here is a description I pulled from the Forum some years ago. No photos.
______________
[QUOTED Article]-
THIS DOC ALSO INCLUDES FB info SO TAKE NOTE!
As you can see, it looks a whole lot better. I've also installed a Home Depot cold air intake, as per the Carl/Pratch tutorial, which seems to help with heat soak during long Solo II events. As an added bonus, there are less things to break and otherwise go wrong with your carb. Essentially all you have to do is remove the two 12mm bolts that hold the two (or three in the case of California) solenoids to the engine, disconnect all the vacuum lines and an electrical connector for the coasting valve and pull the whole mess out.
Once you've done that, you will notice that there was a ground on one of the 12mm bolts, make sure you reattach that ground, because if you leave it out, you will have a very messed up idle and no power. Now here's a vacuum diagram for the '79 model year:
PIC:
_____
I've circled the nipples on the manifold that you will need to use if you want to retain your vacuum advance, as well as the nipple needed to plumb in your new PCV valve to replace the old ventilation and check valve. Here's a closeup of the new vacuum lines, and below it, an extreme closeup of the manifold attachments for the vacuum advance and the PCV valve:
PIC:
_____
If you want to retain your vacuum advance, run two long lengths of vacuum hose from the two nipples circled on the diagram to the vacuum pots on the distributor. If you don't care about vacuum advance, just cap the nipples on the manifold and leave the vacuum pots open to the atmosphere.
I don't have to remind you to cap the unused nipples, lest you have a huge vacuum leak to spoil all the smooth idles to come.
Now, to plumb in the PCV valve, here is what I did. I believe that I have done this correctly, but if any of you see any errors, let me know. Jon has posted a quick little reference in another thread on what you need to do to plumb in a PCV valve, and I shamelessly cribbed from that quick walk thru.
You need to use 5/16th emissions/fuel hose and plumb the PCV valve into the nipple on the oil filler neck. I used a PCV from a '90 Dodge Caravan 3.0L. The smooth end of the valve should be plumbed into the filler neck and the threaded end should be plumbed into the manifold. Next, locate the nipple on the intermediate housing, which is directly below the nipple on the oil filler neck. Run a line from there to the large nipple on the back drivers side of the airbox. Finally, you will need to reconnect the charcoal canister, which is integrated into the lid of the airbox. You will need a 5/16ths tee, so you can run a line from the airbox lid to that tee, which will then go to the carb vent and the fuel tank vent line, which is on the firewall. You will have to clamp the end of the rubber line to the vent line on the firewall, as it is a very loose fit. All the other connections seem pretty tight, but to be on the safe side, clamp those as well.
Q:
okay so if leave the dashpot do i have to do anything different? or how hard is it to take the dashpot out
A:
You don't have to take it off right away if you don't want to. You will have to cap off the nipple on the dashpot though, because it will have a vacuum line going to it from the nest. I forgot all about that until now because I haven't had a dashpot on my carb since I rebuilt it two years ago.
PCV valve substitute:
If you need to give them a vehicle make/model so that they can look it up in the computer tell them you have a '90 Dodge Caravan with the 3L V6. This is the purge valve you're looking for (or anything similar).
Basically you need one that sits in-line, with the vacuum source on one side and the "crankcase" on the other. The threaded end will go towards the manifold vacuum source, the other end will connect to the oil filler neck.
It should be a metal hexagonal-cylinder about three inches long. ANY part store should be able to hook you up for five bucks or less.
Install (81+):
Okay, follow carefully, this is a three-line procedure, and you need about 3ft of 5/16" fuel/emissions/vacuum hose to do it:
Line #1
- Oil Filler Neck goes to non-threaded side of PCV Valve
- Threaded Side of PCV Valve goes to the vacuum source on the intake manifold under where the shutter valve used to be.
I didn't even realize this vacuum source was there until I read some posts on how to do this. It's on the manifold just above the #2 rotor housing
Line #2
There's a connection on the intermediate housing I believe, which juts out towards rotor housing 2. This is just above/ahead of the one on the oil filler neck and would normally have your charcoal canister plugged into it (via a metal tube that follows along the firewall).
- That connection needs a line going to a fresh air source. With the rat's nest removed, that's really easy. There's one on the stock airbox, just above and to the left of the carb vent.
Line #3
Now your charcoal canister isn't hooked to anything.
- Remove the old line that went from the metal tube on the firewall to the intermediate housing. Replace this line with a new one that goes to the carb vent.
-------------
OTHER contributors:
I hooked mine up on my 79 using Mosesx60's diagram,and it didn't want to start.It had a massive vaccuum leak,and was only when I turned the PVC valve orientation around that it worked.My car didn't have A/C,so I didn't have to worry about that.If you do the work,and it doesn't start turn the PVC valve around,and that should fix it.
PCV valves are simple. They have a ball in them, if you shake it and can hear it rattle, the valve is good. To test for orientation, blow in one end, if air passes through it, that is the crankcase side, if not turn it around and blow again. Air passes from the crankcase to the carb only, not the other way around.
_________
The PCV valve that I use has the threaded end going to the intake manifold, and thus is designed to have manifold vacuum on the threaded end.
Only thing missing is to connect the nipple on the center side housing to the filtered section of the air cleaner. There's a nipple on the underside of the SA aircleaner that is a perfect fit.
I just came in here to remind people, do *not* remove solenoid rack/ACV on a SA that still has the thermal reactor. Headers or '81-up manifold only.
_[END QUOTED Article]_____
Stu Aull
80GS
Alaska
https://www.rx7club.com/1st-generati...oblems-422554/
I see your issue with dead-links to Forum articles. Several I have are now dead too. Shame!
Here is a description I pulled from the Forum some years ago. No photos.
______________
[QUOTED Article]-
THIS DOC ALSO INCLUDES FB info SO TAKE NOTE!
As you can see, it looks a whole lot better. I've also installed a Home Depot cold air intake, as per the Carl/Pratch tutorial, which seems to help with heat soak during long Solo II events. As an added bonus, there are less things to break and otherwise go wrong with your carb. Essentially all you have to do is remove the two 12mm bolts that hold the two (or three in the case of California) solenoids to the engine, disconnect all the vacuum lines and an electrical connector for the coasting valve and pull the whole mess out.
Once you've done that, you will notice that there was a ground on one of the 12mm bolts, make sure you reattach that ground, because if you leave it out, you will have a very messed up idle and no power. Now here's a vacuum diagram for the '79 model year:
PIC:
_____
I've circled the nipples on the manifold that you will need to use if you want to retain your vacuum advance, as well as the nipple needed to plumb in your new PCV valve to replace the old ventilation and check valve. Here's a closeup of the new vacuum lines, and below it, an extreme closeup of the manifold attachments for the vacuum advance and the PCV valve:
PIC:
_____
If you want to retain your vacuum advance, run two long lengths of vacuum hose from the two nipples circled on the diagram to the vacuum pots on the distributor. If you don't care about vacuum advance, just cap the nipples on the manifold and leave the vacuum pots open to the atmosphere.
I don't have to remind you to cap the unused nipples, lest you have a huge vacuum leak to spoil all the smooth idles to come.
Now, to plumb in the PCV valve, here is what I did. I believe that I have done this correctly, but if any of you see any errors, let me know. Jon has posted a quick little reference in another thread on what you need to do to plumb in a PCV valve, and I shamelessly cribbed from that quick walk thru.
You need to use 5/16th emissions/fuel hose and plumb the PCV valve into the nipple on the oil filler neck. I used a PCV from a '90 Dodge Caravan 3.0L. The smooth end of the valve should be plumbed into the filler neck and the threaded end should be plumbed into the manifold. Next, locate the nipple on the intermediate housing, which is directly below the nipple on the oil filler neck. Run a line from there to the large nipple on the back drivers side of the airbox. Finally, you will need to reconnect the charcoal canister, which is integrated into the lid of the airbox. You will need a 5/16ths tee, so you can run a line from the airbox lid to that tee, which will then go to the carb vent and the fuel tank vent line, which is on the firewall. You will have to clamp the end of the rubber line to the vent line on the firewall, as it is a very loose fit. All the other connections seem pretty tight, but to be on the safe side, clamp those as well.
Q:
okay so if leave the dashpot do i have to do anything different? or how hard is it to take the dashpot out
A:
You don't have to take it off right away if you don't want to. You will have to cap off the nipple on the dashpot though, because it will have a vacuum line going to it from the nest. I forgot all about that until now because I haven't had a dashpot on my carb since I rebuilt it two years ago.
PCV valve substitute:
If you need to give them a vehicle make/model so that they can look it up in the computer tell them you have a '90 Dodge Caravan with the 3L V6. This is the purge valve you're looking for (or anything similar).
Basically you need one that sits in-line, with the vacuum source on one side and the "crankcase" on the other. The threaded end will go towards the manifold vacuum source, the other end will connect to the oil filler neck.
It should be a metal hexagonal-cylinder about three inches long. ANY part store should be able to hook you up for five bucks or less.
Install (81+):
Okay, follow carefully, this is a three-line procedure, and you need about 3ft of 5/16" fuel/emissions/vacuum hose to do it:
Line #1
- Oil Filler Neck goes to non-threaded side of PCV Valve
- Threaded Side of PCV Valve goes to the vacuum source on the intake manifold under where the shutter valve used to be.
I didn't even realize this vacuum source was there until I read some posts on how to do this. It's on the manifold just above the #2 rotor housing
Line #2
There's a connection on the intermediate housing I believe, which juts out towards rotor housing 2. This is just above/ahead of the one on the oil filler neck and would normally have your charcoal canister plugged into it (via a metal tube that follows along the firewall).
- That connection needs a line going to a fresh air source. With the rat's nest removed, that's really easy. There's one on the stock airbox, just above and to the left of the carb vent.
Line #3
Now your charcoal canister isn't hooked to anything.
- Remove the old line that went from the metal tube on the firewall to the intermediate housing. Replace this line with a new one that goes to the carb vent.
-------------
OTHER contributors:
I hooked mine up on my 79 using Mosesx60's diagram,and it didn't want to start.It had a massive vaccuum leak,and was only when I turned the PVC valve orientation around that it worked.My car didn't have A/C,so I didn't have to worry about that.If you do the work,and it doesn't start turn the PVC valve around,and that should fix it.
PCV valves are simple. They have a ball in them, if you shake it and can hear it rattle, the valve is good. To test for orientation, blow in one end, if air passes through it, that is the crankcase side, if not turn it around and blow again. Air passes from the crankcase to the carb only, not the other way around.
_________
The PCV valve that I use has the threaded end going to the intake manifold, and thus is designed to have manifold vacuum on the threaded end.
Only thing missing is to connect the nipple on the center side housing to the filtered section of the air cleaner. There's a nipple on the underside of the SA aircleaner that is a perfect fit.
I just came in here to remind people, do *not* remove solenoid rack/ACV on a SA that still has the thermal reactor. Headers or '81-up manifold only.
_[END QUOTED Article]_____
Stu Aull
80GS
Alaska
Last edited by 7aull; 10-31-16 at 04:22 AM.
10-31-16, 03:37 AM
#3
Here is a SECOND Thread I pulled on Rats Removal:
I have not vetted these so do CROSS-CHECK the procedures outlined btw this and previous post....
___[QUOTED Article]:___
The shopping list.
4 Feet 5/32 Vacuum hose
2 Feet 5/16 Vacuum hose
1 - 5/32 T-Fitting
1 - 5/16 T-Fitting
3 - 5/32 vacuum cap
1 - Universal Fitting (plastic piece that allows 2 different size ends)
1 - Ring terminal 16-14 gauge (replaces original ground) wait to buy will need to make sure a 12mm bolt that holds the rats nest rack will fit it.
1.Disconnect all hoses from rats nest and label them:
a.2 hoses from distributer
b.1 hose from crankcase
c.4 hoses from carburetor
d.2 hoses from coasting valve
e.1 hose throttle opener
f.3 hoses from carb hat
g.1 hose next to air vent solenoid valve (on carb)
h.1 hose at altitude compensator
i.1 hose on top of check valve
2.Remove the bolts
a.10mm that holds the Ventilation check valve (located on rats nest rack). The ground should be bolted here.
b.3 12mm bolts. 2 are located at the rats nest and on is located by the coasting valve securing the 4 grouped hoses running to the carb.
3.Disconnect the 3 connections from rats nest (orange, blue and white) and on electrical clip located at coasting valve. Pull the nest out carefully
4.Now that everything is out. Its time to re-run the hoses:
a.Distributer
i.5/32 hose from trailing and leading cut to your liking. Place t-fitting between the leading and trailing and run 5/32 hose to second nipple on left of carb.
b.Venting crankcase
i.5/16 hose from crankcase running to 5/16 T-fitting the other 2 connections from t-fitting will rung to the nipple next to air vent solenoid valve on carb and charcoal canister.
c.Venting oil filler neck and gas tank vent line (using existing check valve)
i. the 3rd nipple located at the bottom of check valve. 5/32 hose to the two way adapter on the other side of adapter 5/16 hose to the bottom nipple next to automatic transmission (already capped)
ii.the nipple located on top of check valve run 5/32 hose to altitude compensator
d.Cap the 3 nipple left open and seal the two lines coming from bottom of carb hat. (I used tape for now). Not sure about throttle opener… I left uncapped for now
5. Cut the ring terminal from ground replace it with a larger one using a 12mm bolt that held the rats nest to the block secure to any of the threaded locations that are now open.
________[END QUOTE]______
I Also have a very descriptive PDF with images that is too big to Post here, but if you want to PM me with your email, I can drop it to you direct...
Stu Aull
80GS
Alaska
I have not vetted these so do CROSS-CHECK the procedures outlined btw this and previous post....
___[QUOTED Article]:___
The shopping list.
4 Feet 5/32 Vacuum hose
2 Feet 5/16 Vacuum hose
1 - 5/32 T-Fitting
1 - 5/16 T-Fitting
3 - 5/32 vacuum cap
1 - Universal Fitting (plastic piece that allows 2 different size ends)
1 - Ring terminal 16-14 gauge (replaces original ground) wait to buy will need to make sure a 12mm bolt that holds the rats nest rack will fit it.
1.Disconnect all hoses from rats nest and label them:
a.2 hoses from distributer
b.1 hose from crankcase
c.4 hoses from carburetor
d.2 hoses from coasting valve
e.1 hose throttle opener
f.3 hoses from carb hat
g.1 hose next to air vent solenoid valve (on carb)
h.1 hose at altitude compensator
i.1 hose on top of check valve
2.Remove the bolts
a.10mm that holds the Ventilation check valve (located on rats nest rack). The ground should be bolted here.
b.3 12mm bolts. 2 are located at the rats nest and on is located by the coasting valve securing the 4 grouped hoses running to the carb.
3.Disconnect the 3 connections from rats nest (orange, blue and white) and on electrical clip located at coasting valve. Pull the nest out carefully
4.Now that everything is out. Its time to re-run the hoses:
a.Distributer
i.5/32 hose from trailing and leading cut to your liking. Place t-fitting between the leading and trailing and run 5/32 hose to second nipple on left of carb.
b.Venting crankcase
i.5/16 hose from crankcase running to 5/16 T-fitting the other 2 connections from t-fitting will rung to the nipple next to air vent solenoid valve on carb and charcoal canister.
c.Venting oil filler neck and gas tank vent line (using existing check valve)
i. the 3rd nipple located at the bottom of check valve. 5/32 hose to the two way adapter on the other side of adapter 5/16 hose to the bottom nipple next to automatic transmission (already capped)
ii.the nipple located on top of check valve run 5/32 hose to altitude compensator
d.Cap the 3 nipple left open and seal the two lines coming from bottom of carb hat. (I used tape for now). Not sure about throttle opener… I left uncapped for now
5. Cut the ring terminal from ground replace it with a larger one using a 12mm bolt that held the rats nest to the block secure to any of the threaded locations that are now open.
________[END QUOTE]______
I Also have a very descriptive PDF with images that is too big to Post here, but if you want to PM me with your email, I can drop it to you direct...
Stu Aull
80GS
Alaska
Last edited by 7aull; 10-31-16 at 04:26 AM.
10-31-16, 03:50 AM
#4
if you're just trying to delete the rats nest, just unbolt it (one or two bolts on the top of the engine in the copper hosing) and pull off all the hoses going to anything on the engine or carb or manifold, each time you pop a hose off just replace it with a cap 
all the information above is great though
all the information above is great though
10-31-16, 08:43 AM
#5
Junior Member
Thread Starter
Nice! Thanks for digging that up for me.. For some reason I was unable to find a good, clear description. When I get home I will take care of it :-) I'm going to have to buy some vacuum line and connectors and I will be set.