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Discussion Starter · #1 ·
I was just messing around yesterday and I noticed that if I blocked the hole in my PCV the idle speed dropped and smoothed out noticably. The question is do I need to have this hooked up? It seems to me that even when working properly engine vacuum is lost through the crankcase. Besides it seems better to not have the engine eat its own noxious vapors. Is this a good thing? Or am I asking to start blowing seals? I have a vented oil cap and I could install one of those old draft tubes from the early 60's. I took it out for a short test drive and it seemed a little peppier.
Any advise is appreciated.


66 Coupe
C Code
http://biology2.biosci.wayne.edu/dave/must/st1i.jpg
 

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You may want to replace the PCV valve. The engine RPM should not decrease too much when you plug the PCV at idle. The spring may be weak, causing an excessive vacuum leak.

they are pretty cheap, and widely available. Also, the alternative to a PCV is a draft tube, which would deposit oil all over the underside of the car if you've got excessive blow-by.


Steve Leslie, 65 coupe in restoration. 302, toploader, A/C, disc brakes, bench seat

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There's nothing wrong with the engine eating "its own noxious vapors", as these vapors are flamable. The PCV system does cause an inherent vaccum leak, however, but is compensated for by propper carb tuning. If you don't get those fumes out of the crankcase, they will contaminate your oil. This is fine on a track car as the oil is constantly being changed, but not so good on a daily driver.

If you always do what you've always done,
You'll always get what you've always got

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Discussion Starter · #4 ·
Thanks guys. thats pretty much what I thought but it good to hear from people who know. I will get a replacement valve and check out the hose to make sure there isn't too much leakage..

66 Coupe
C Code
http://biology2.biosci.wayne.edu/dave/must/st1i.jpg
 
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