Trying to understand pcv routing
03-09-09, 11:13 AM
#1
Trying to understand pcv routing
Removed the rats nest and broke the $50 purge valve. Thanks to the tutorial inthe FAQ it went very smoothy. I was very happy with the overall results. Did a search and found ten different ways to hook a pcv up. So I have a few questions.
What is he center rotor vacuum port? Is that with the 6 ports at the carb or is it the block off plate on the housing itself by the filler neck?
The nipple atop the carb by the fuel inlet. Is this vacuum or vent? Cars not running at the moment or I'd check
Makes the most sense to me to run a breather on the oil filler and run the inline pcv from vacuum to crankcase(maybe the center block off plate as formentioned).
Thanks for input in advance!
-Paul
What is he center rotor vacuum port? Is that with the 6 ports at the carb or is it the block off plate on the housing itself by the filler neck?
The nipple atop the carb by the fuel inlet. Is this vacuum or vent? Cars not running at the moment or I'd check
Makes the most sense to me to run a breather on the oil filler and run the inline pcv from vacuum to crankcase(maybe the center block off plate as formentioned).
Thanks for input in advance!
-Paul
03-09-09, 12:17 PM
#2
Lives on the Forum
What I did, which was so simple that most don't believe it will work was this:
Run a vaccum line from the nipple on the oil filler tube, and connect it to any one of the nipples at the base of the carb that shows vacuum at idle (some show vacuum at idle, while others show vacuum only under throttle). That's it. No signs of "lung mustard" showing up under the oil cap or any other condensation issues (which is the whole reason for doing this in the first place).
Others insist that you need a pcv valve somewhere in there, but I've never had any issues with my simple setup.
Hope this helps...
.
Run a vaccum line from the nipple on the oil filler tube, and connect it to any one of the nipples at the base of the carb that shows vacuum at idle (some show vacuum at idle, while others show vacuum only under throttle). That's it. No signs of "lung mustard" showing up under the oil cap or any other condensation issues (which is the whole reason for doing this in the first place).
Others insist that you need a pcv valve somewhere in there, but I've never had any issues with my simple setup.
Hope this helps...
.
03-09-09, 08:43 PM
#5
Well I went ahead and got the Caravan PCV valve and installed it. Actually made for a clean install. 5/16 line from the bowl to a 45ºTee running to the PCV then into the carb nipple, the other end over to the filler cap.
Gotta say the car runs 100times better without that stupid shutter valve! Doesn't jerk when cruising, acceleration from no throttle say around a 90º corner is nice and smooth now and not jerky! IT also doesn't idle ridiculously high either! Now to get it on the lift this week and take care of the Air Valve to the cat!
Thanks for the help guys!
Gotta say the car runs 100times better without that stupid shutter valve! Doesn't jerk when cruising, acceleration from no throttle say around a 90º corner is nice and smooth now and not jerky! IT also doesn't idle ridiculously high either! Now to get it on the lift this week and take care of the Air Valve to the cat!
Thanks for the help guys!
10-04-11, 11:14 AM
#6
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Well I went ahead and got the Caravan PCV valve and installed it. Actually made for a clean install. 5/16 line from the bowl to a 45ºTee running to the PCV then into the carb nipple, the other end over to the filler cap.
Gotta say the car runs 100times better without that stupid shutter valve! Doesn't jerk when cruising, acceleration from no throttle say around a 90º corner is nice and smooth now and not jerky! IT also doesn't idle ridiculously high either! Now to get it on the lift this week and take care of the Air Valve to the cat!
Thanks for the help guys!
Gotta say the car runs 100times better without that stupid shutter valve! Doesn't jerk when cruising, acceleration from no throttle say around a 90º corner is nice and smooth now and not jerky! IT also doesn't idle ridiculously high either! Now to get it on the lift this week and take care of the Air Valve to the cat!
Thanks for the help guys!
What I did, which was so simple that most don't believe it will work was this:
Run a vaccum line from the nipple on the oil filler tube, and connect it to any one of the nipples at the base of the carb that shows vacuum at idle (some show vacuum at idle, while others show vacuum only under throttle). That's it. No signs of "lung mustard" showing up under the oil cap or any other condensation issues (which is the whole reason for doing this in the first place).
Others insist that you need a pcv valve somewhere in there, but I've never had any issues with my simple setup.
Hope this helps...
.
Run a vaccum line from the nipple on the oil filler tube, and connect it to any one of the nipples at the base of the carb that shows vacuum at idle (some show vacuum at idle, while others show vacuum only under throttle). That's it. No signs of "lung mustard" showing up under the oil cap or any other condensation issues (which is the whole reason for doing this in the first place).
Others insist that you need a pcv valve somewhere in there, but I've never had any issues with my simple setup.
Hope this helps...
.
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10-04-11, 08:24 PM
#8
Brake booster gets straight full manifold vacuum from the side of the intake manifold (rear engine).
The PCV is a controlled Vacuum Leak.
The Mitsu/Dodge inline pcv I have is plumbed to the larger manifold vacuum port on the drivers side of the intake/carb. So it goes from that nipple, to the pcv valve, to a TEE which one goes to the carb vent (as my solenoid is dead and removed) and the other goes to the fitting on the oil fill tube. Then the nipple below that I have a small RC car filter on it. Works great for over two years. I'll post a pic tomorrow in the daylight.
The PCV is a controlled Vacuum Leak.
The Mitsu/Dodge inline pcv I have is plumbed to the larger manifold vacuum port on the drivers side of the intake/carb. So it goes from that nipple, to the pcv valve, to a TEE which one goes to the carb vent (as my solenoid is dead and removed) and the other goes to the fitting on the oil fill tube. Then the nipple below that I have a small RC car filter on it. Works great for over two years. I'll post a pic tomorrow in the daylight.
10-06-11, 08:11 PM
#11
I'm using a 2257 valve. It's pipe taped on the suction side (carb side) and a large nipple on the other side attached to the carb vent and the block nipple by the oil filler. The threaded end was actually very easy to just screw into the right sized vacuum line for the nipple I have it on.
Two years and never any lung butter/mustard whatever lol.
Two years and never any lung butter/mustard whatever lol.
10-06-11, 08:34 PM
#12
That sounds like the ones I use ie threaded on one side (BSP or NPT, depending) and a nipple on the other.
I guess it doesn't really matter all that much as most PCV valves work in a similar fashion. They shouldn't pass a whole lot of air right at idle as this would cause a vacuum leak-like condition, but will suck a fair amount just above idle where it's less of a problem and can pull more water vapor from the "crankcase" more effectively.
I guess it doesn't really matter all that much as most PCV valves work in a similar fashion. They shouldn't pass a whole lot of air right at idle as this would cause a vacuum leak-like condition, but will suck a fair amount just above idle where it's less of a problem and can pull more water vapor from the "crankcase" more effectively.
10-06-11, 08:58 PM
#13
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I must have another small vac leak some where because everytime I install a pcv it acts like a vac leak. Must be time to replace all the dry rotted vac caps lol as I have no idea where else I would have a vac leak with no emissions or rats nest. Anybody got any tricks to keep vac caps from dry rotting? Right now I'm just running a vac hose from the nipple on the housing near the filler tube to a nipple on the air cleaner and I have no lung mustard but a tiny bit of moisture on the bottom of the oil cap.
10-06-11, 10:22 PM
#15
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Right but it should be a very small vac leak that you are able to over come by tuning. When I intalled the pcv it wouldn't idle down and idles really rough unless I give it a ton of fuel.
10-06-11, 11:47 PM
#16
That sound contradictory. If it idled high, that means by introducing a vacuum leak you leaned out the mixture causing it to run better.
What other stuff do you have connected? And when you hook the PCV up, where do you hook it up to and do you have it plumbed the correct direction?
What other stuff do you have connected? And when you hook the PCV up, where do you hook it up to and do you have it plumbed the correct direction?
10-06-11, 11:53 PM
#17
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Higher idle doesn't necessarily mean better. I tried the brake booster hose and just bellow the carb and I had the idle screw backed all the way off and it was idling at 1k then I gave it less fuel and the idle got really choppy.
10-07-11, 09:36 PM
#21
LOL not quite. The crankcase gases join the carb vent line.... which are both under vacuum from the intake. So both sets of gases are set back into the combustion chamber under vacuum from beneath the carb. The filter on the filler neck is the "breather."