A stupid PCV Valve question.. Sorry. - Vintage Mustang Forums

 
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post #1 of 10 (permalink) Old 10-13-2007, 05:17 PM Thread Starter
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I've been hearing a rattling in the upper end side of the motor,, banks 1-4 (351W)... thought it might be coming from the pcv valve cause im getting some rattling from it... When I remove the pcv valve from the valve cover with the motor running and place my finger over it, it immediately sticks to my finger, (ton of vacuum).. However when i place it back in the valve cover the valve inside the unit immediately starts to rattle open and close.. It does this regardless if im at idle or if i work the carb. to about 2k rpm....

is this normal??

in the past i've hooked up a vacuum guage to the carb./manifold and i get about 16 1/2 -17 psi at idle..

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post #2 of 10 (permalink) Old 10-13-2007, 06:22 PM
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Just an idea but is the grommet around the PCV valve worn out? Maybe it isn't sealing correctly and allow the vacuum to pull around it causing the valve to rattle.

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post #3 of 10 (permalink) Old 10-13-2007, 06:45 PM Thread Starter
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doesnt appear to be suffering from dry rot.. still pliable.. aluminum "mustang powered by ford" valve covers that are baffled... 3 years old..


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post #4 of 10 (permalink) Old 10-14-2007, 08:57 AM Thread Starter
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anyone else??

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post #5 of 10 (permalink) Old 10-14-2007, 01:50 PM
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I am not so good in writing or explaining this in english but i try.
Your pcv valve should be connected to the manifold or just below your carburator.
On the other hand you need a breather cap on the other valve cover connected or not to the airfilter.Filtered air gets through the breather oilcap in the engine and travels through the engine to the other side where it gets through the pcv valve in the combustion chamber.Why ? Some fuel particals find their way beside the piston to the carter , when you have bad ignition or bad entilation , our oillevel will rise and your engine will be lubricated with a mixcure of fuel and oil.
Hope you nderstand what am talking about.
search the net for : Positive crankcase ventilation system.

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post #6 of 10 (permalink) Old 10-14-2007, 02:41 PM Thread Starter
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what i am wondering is should i be getting the pcv valve to chatter when at idle.. like i said ill remove the pcv valve while at idle and insert my finger on the end of it and get plenty of suction...

also, does it matter as to which valve cover i have the pcv valve inserted in??
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post #7 of 10 (permalink) Old 10-14-2007, 05:37 PM
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Don't think it matters which valve cover the pcv valve goes into. I've usually seen it in the passenger side rear part of the valve cover simply because it was easier to vent to the base of the carb in the back of the engine. The one question I guess I have is: have you replaced the pcv valve itself, just to see if it changes anything. I don't know if I've ever heard one just rattle while the engine is running.

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post #8 of 10 (permalink) Old 10-14-2007, 05:43 PM
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Never had one rattle when running either. I say replace the PCV with a new for the proper application and then check on the rattle.


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post #9 of 10 (permalink) Old 10-14-2007, 05:55 PM
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Quote:
Originally Posted by AzPete
Never had one rattle when running either. I say replace the PCV with a new for the proper application and then check on the rattle.
I agree. Just replace the PCV valve and you should be good to go. The little ball inside may be worn completely out.


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post #10 of 10 (permalink) Old 10-15-2007, 03:22 PM
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Open the oil filler cap a bit and see what the pcv does.Probably it stops so the oil filler cap does not breath.How reads your vacuum meter at idle.Is it steady?

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