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Discussion Starter #1
So since I replaced my heads and cam I have had some idle issues. The idle was very inconsistent. I think I finally figured it out to be the PCV valve. Since I a pulling less vacuum than I was before the valve was not closing at idle when I would try to idle below 850. I was using a pcv valve with essentially the same configuration as stock 289 valve but with the right angle elbow. It 13 inches of vacuum it would rattle and buzz like crazy. I tried the fram fv181 (stock for boss 302)which is supposed to have low vacuum closing threshold. It was the same as my other one. I did run a fixed orifice valve which was better, but give no backfire protection, and doesn't adjust for idle, , cruise, acceleration, or WOT. I think I found one that seems to fit the bill. It's a PCV for a Ford 2.3 four cylinder. It's staying closed at idle. I will post back if there are any issues as far as driving go. I know this PCV is not made for the engine and is not tailored to the performance specifications. I eventually want to change over to one of the M/E Wagner adjustable units. Anyone have experience with one?
 

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I eventually want to change over to one of the M/E Wagner adjustable units. Anyone have experience with one?
I have one and no problems with it.
Several others should have them also as somebody here arranged for a group buy at a discount a couple of years ago.
 

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Never let it be said that I haven't always been better at taking things apart than putting them back together but.......

If you can get one apart without destroying it and cut down the spring you might successfully "tweak" it. FWIW, Summit's billet PCV is cheap and can be disassembled, but they don't list any parts for it.
 

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Discussion Starter #4
I thought for sure the fv181 valve would work. I have seen several people on different forums say that it worked for them on 12-15 inches of vacuum. I wonder if I have a vacuum leak that is undiagnosed. When I place a vacuum gauge on my engine I don't get a steady needle. It kind of vibrates really fast just to either side of 13. I have sprayed all around the intake and carb base but haven't noticed a change in my idle when i do. Is that normal for a larger cam to have a more inconsistent vacuum signal?
 

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I thought for sure the fv181 valve would work. I have seen several people on different forums say that it worked for them on 12-15 inches of vacuum. I wonder if I have a vacuum leak that is undiagnosed. When I place a vacuum gauge on my engine I don't get a steady needle. It kind of vibrates really fast just to either side of 13. I have sprayed all around the intake and carb base but haven't noticed a change in my idle when i do. Is that normal for a larger cam to have a more inconsistent vacuum signal?
How MUCH of a "vibration"? My first thought would be too much valve preload or rail rockers used with non-rail retainers or loose valve guides.
 

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Discussion Starter #6
The needle just vibrates rapidly around 13. Less than an inch worth of vacuum worth of movement. I am using full roller rockers with valve guides. They are set to 1/2 turn past zero lash.
 

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The needle just vibrates rapidly around 13. Less than an inch worth of vacuum worth of movement. I am using full roller rockers with valve guides. They are set to 1/2 turn past zero lash.
Could, then, just be the action of the PCV that's causing the needle movement. Does it go away when you stick your thumb over the end?
 

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If you can get one apart without destroying it and cut down the spring you might successfully "tweak" it. FWIW, Summit's billet PCV is cheap and can be disassembled, but they don't list any parts for it.
If you believe that the PCV is at fault and want to "tweak" one, the Summit part that Woodchuck referenced would be a great starting point. I run one and have had mine apart several times. The spring is nothing special IIRC. You should easily find replacements of different spring rates to experiment with.
738819
 
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I also have an ME/Wagner adjustable PCV valve. I originally bought it in efforts of trying to fix some idle issues (it helped.) Now i am using it on my 331 with sniper EFI, the builder of my engine highly recommended them...i just happened to have one.
 

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Discussion Starter #10
I will try the idea of putting my finger over the PCV and see if the vacuum smooths out. The valve from the 2.3L engine seems to be doing an ok job. But I have read nothing but good things about the M/E Wagner valve. I worry that there is a leak on the intake that I can't see or find easily.
Also would the fact that I am using a dual plane manifold have anything to do with the bouncing needle? Like maybe the vacuum line of the carb I am using is getting pulsating vacuum signals from each side? It would be ideal to pull a signal straight from a port on the manifold, but I think that port on the back of the manifold only sees vacuum from one plane. Wouldn't that give me a false reading as well?
 

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Discussion Starter #11
Update. My idle has smoothed out recently and the vacuum gauge is reading a little more steady right around 14.5 inches It still fluctuates slightly but maybe only about .5 inch total. I think maybe the vacuum leak somehow has sealed itself up. I feel like I should take the opportunity while it's running good to check and tighten the intake manifold. Hopefully that keeps the leak sealed for good.
 

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If you believe that the PCV is at fault and want to "tweak" one, the Summit part that Woodchuck referenced would be a great starting point. I run one and have had mine apart several times. The spring is nothing special IIRC. You should easily find replacements of different spring rates to experiment with.
View attachment 738819
Right. Remember that a LIGHTER spring will be needed to accommodate a lower vacuum signal and vice-versa.
 
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