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PCV valve

ltatro

Jr. Member
Joined
Feb 10, 2002
Messages
129
Loc.
Michigan
Anyone running an "inline" PCV valve on the motor. Using the 5.0 steel valve covers I need to run an inline and was wondering what type of valve they were using. Was told that the valves are "engine specific" and want to make sure I get the right one. p.s. still working on idle problem
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
43,498
You're using the EFI covers only on a carbbed engine? Or are you running EFI too? Where do you put the oil in on your setup?
You're right, they are engine specific, but there is a fairly broad range so it might be possible to find an inline one that would work. Hopefully anyway. You may just have to go on down to your favorite shop that stocks a boatload of PCV's out on the shelves and go through the boxes and each time you find one that looks promising, verify what type of engine it's off of just to get an idea.
I'm not sure of every parameter. Like if it's just the vacuum reading in lbs, or if it's also volume specific, meaning that it might have to be from a V8 to work. I don't know. Maybe a V6 or even a 4 cylinder would work if it meets other criteria.
My current one is a mid-seventies Chevy unit with a 90° bend and a 3/8" barb. The same style from a Ford 302 let way too much air in and it ran super lean, so not all V8's are created equal.
Where are you tapping the fresh air inlet into? Just curious how you have yours set up.
Good luck. Hopefully someone will have a better answer.

Paul
 
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ltatro

Jr. Member
Joined
Feb 10, 2002
Messages
129
Loc.
Michigan
I'm running a carb (autolite 2100 on a late model 5.0 motor. I ended up using two sets of 5.0 covers to get the right set-up, baffled holes on each side. I use the passenger side as my oil intake point, running my PCV hose off the oil snout tube to the back of the spacer plate under the carb. The drivers side (at rear) has my fresh air intake connected to the bottom of the stock air cleaner. I picked up a PCV valve at the local NAPA, similiar to an original 302 valve in size, etc., and just used it inline. My problem has been getting this thing to idle. Just eliminated all unnecessary vacuum lines from front of motor in hopes of finding my problem.
 
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ltatro

Jr. Member
Joined
Feb 10, 2002
Messages
129
Loc.
Michigan
picture shows how I have the valve routed, you can see it just above the wires, inline
 

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70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
DirtDonk said:
My current one is a mid-seventies Chevy unit with a 90° bend and a 3/8" barb.
I'm glad someone posted a PCV valve question. I decided not to go with the valve listed for the 302 only 'cause the outlet stuck straight up in the air. Wanted something that looked cleaner. I just picked up what I think is the same one as DirtDonk, Mid-70's Chebby 350cid, but I haven't had a chance to try it out yet.

I know not all PCV valves are created equal, so I was trying to find the type of information DirtDonk was refering to (vacuum, orifice size, etc) but I've come up dry. Does anyone have a source for the technical specs for PCV valves???
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
43,498
Itatro, would reversing the order help eliminate the problem? Using the oil filler port as the clean air intake (like Ford does) and using the other one to mount a standard type of PCV? I can't see the other side so I don't know what kind of grommet you have in there, but if it's even close to a standard type, then I would try the valve in the drivers side cover and pull clean air in the passenger side. That way you probably have more choices in valves.
One thing I like to do so I don't have to try to adapt hoses or have rubber line snaking all over the compartment, is to just run a couple inches of rubber 3/8" line at each end and custom bend steel tubing to work it's way from the carb port to the valve. Looks super clean that way and works well with less hose deterioration to worry about over the years.

70Steve, I actually did an experiment years ago, way before the internet was there with so much information, and I just bought 5 or 6 units that had the same basic design as I wanted. Probably the same thing you're running. With the 90° elbow, I was a happy camper. I only kept two after trying them all. The 350 Chevy one and the Ford one that didn't work right. All the others seemed to work decently but I felt the Chevy one gave me the best running of them all. Of course, that may just be what worked with my carb jetting at the time, but I'm not completely sure.
My brainstorm was that the one that let if run so lean that it stumbled off-idle (it did idle ok though) would be perfect for high altitude running. So, instead of re-jetting the carb every time I went from sea-level to 9000 feet, I just swapped PCV's at a convenient rest stop. Actually works pretty good too.
I think the application was for like a Granada with 302 but can't remember.
I notice that the "pill" inside the valves have different numbers on them and may be a weight rating or something but don't have your answer for you either.
Hopefully someone will have that info or a link to study. I haven't even tried a search yet, but may as soon as I get back.
Good luck.
Oh, and just what is your idling problem? I don't remember seeing other threads about it but if there is one, point me in the right direction and I'll check it out. Maybe I did already but I can't remember.

Paul
 
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ltatro

Jr. Member
Joined
Feb 10, 2002
Messages
129
Loc.
Michigan
The fresh air inlet is on the driver's side valve cover, at the rear. There is just enough clearance under the accelerator rod to fit the hose for the fresh air to air cleaner (5.0 valve cover is raised slightly where the baffle is). I cut the tube flush with the cover and installed a rubber grommet and plastic elbow for the hose. Does it matter which way it is routed from side to side? My old 302 was routed in reverse, PCV on driver's side. I have seen it routed the other way on later 60' 289's, that is passenger for PVC. I just figured as long as there was a direction of flow you could use either side. Thoughts? Tater
 

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ltatro

Jr. Member
Joined
Feb 10, 2002
Messages
129
Loc.
Michigan
Dirtmonk, Oh, my idling problem is as follows: Just finished the 5.0 project and had initial startup. Seems to run through the choke cycle (revs pretty high) once off choke it doesn't want to stay idling. I have to "feather" the pedal to keep the RPM's up but once off the gas it stumbles and stops. Starts right back up but won't idle. I've had the carb back apart, checked for dirt in fuel line, bowl, jets, booster, etc. All that stuff is very clean. I removed the front vacuum ports from the intake and thermo housing, and capped them. Running vacuum to the dist. from port underneath carb, brake, trans, at back of intake. I haven't tried staring it since I've made those changes. Had alot of good info from Rustytruck that I have yet to try. I figure it's running very lean (eye's were burning in the garage). Hoping to eliminate any vacuum leaks etc. before I move on to carb adjustment (idle fuel mixture) etc. Carb was completely rebuilt and plated and I assume it was set to specs before it was sent out. Anyways, it gets pretty frustrating. tater
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
43,498
Nope, direction doesn't matter. As long as you've got an out-with-the-bad, in-with-the-good situation, and the manifold vacuum is hooked to the valve, not the breather, you're OK. I guess they went by which side was convenient on each particular application. I'm guessing though.
Hey, Frustrating is a Bronco's middle name sometimes.
Sounds like you're on the right track with looking for vacuum leaks and such. I'm assuming that you tried adjusting the idle up with the screw and didn't have any luck, but if so, what did it do then? And have you had a chance to mess with the mixture screws? When it won't idle, it's kind of hard to adjust them, but sometimes just messing with them will net you enough improvement to keep you going.
It sounds like you may also have the vacuum advance hooked up to the wrong port. On a setup like yours, you have to have it to a ported vacuum source and those are "usually" up higher on the carb. The lower ones are usually below the throttle plate and get full manifold vacuum and the ones above get their signal from a slot adjacent to the throttle plate so it only has a vacuum signal AFTER you start to open the throttle.
Some vehicles DO use manifold vacuum from the factory, but most by far, including the Broncos use ported spark.
At the very least, if you're not sure what this one has, disconnect it temporarily while you're messing with the idle.
Also, check for a VERY good spark. The leaner you get the harder it is to ignite the mix, so a good spark is a must. Which ignition system are you using?
Those are a few thoughts I had off the top of my head but if anything else pops up I'll throw 'em out there when I get back.
Good luck.

Paul
 
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ltatro

Jr. Member
Joined
Feb 10, 2002
Messages
129
Loc.
Michigan
Old time ignition system, mallory dual point with a stock coil (filco, when's the last time you heard "filco"), I know, I just like messing with points, it's old school. tater
 

MnkyBiz

Bronco Guru
Joined
Jan 17, 2004
Messages
3,758
Loc.
Northern VA/DC
Thanks for sharing the knowledge 73Stallion!

I like a lot of their stuff, and usually tell others that they good items. Sharing with us that these are bad items is good help!
 

Skuzzlebutt

PhD, Dr. of Broncology
Joined
May 26, 2001
Messages
4,393
Loc.
Honeymoon Bay
Have y'all tried using a vacuum gauge to judge which valve suits your engine best? I haven't, but it sounds like the right thing to do.
 
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