PCV/breather...full Vac...Vac pump...? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Longhorn Man · 09-01-2002, 03:34 PM

Ok, you that I have you wondering what the heck I'm talking about...
For the best part, we all know that one of the best ways to ventilate our engines, is a breather and PCV valve.
Many drag racers have been using vac pumps to create a cavume inside the engen. This makes the rings seal better, and reduces blow by, ect ect ect.
NOW, What if I were to just run a straight hose from the valve covers, to the carb? I have fittings on both valve covers, and they are even aimed at the carb. Would this be of any benifit? Would it do any harm?
Am I on crack?

mikep · 09-01-2002, 03:48 PM

PCV valves are designed to close under light vacuum situations such as WOT . Thats what that little spring thingy and valve setup is inside them. They close at WOT which, coincidentally, is when your engine is producing the most blow by. So you have a close PCV system and a whole buttload of crankcase gasses bottled up inside your motor which will either blow your dipstick out or blow your PCV valves out of their holes and make a big old oily mess.

Tried it. Won't try it again!

Longhorn Man · 09-01-2002, 04:52 PM

OK, not the first time I had a creak head idea. Thanks.

09-01-2002, 03:34 PM	#1
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	PCV/breather...full Vac...Vac pump...? Ok, you that I have you wondering what the heck I'm talking about... For the best part, we all know that one of the best ways to ventilate our engines, is a breather and PCV valve. Many drag racers have been using vac pumps to create a cavume inside the engen. This makes the rings seal better, and reduces blow by, ect ect ect. NOW, What if I were to just run a straight hose from the valve covers, to the carb? I have fittings on both valve covers, and they are even aimed at the carb. Would this be of any benifit? Would it do any harm? Am I on crack? Attached Images

09-01-2002, 03:48 PM	#2
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	PCV valves are designed to close under light vacuum situations such as WOT . Thats what that little spring thingy and valve setup is inside them. They close at WOT which, coincidentally, is when your engine is producing the most blow by. So you have a close PCV system and a whole buttload of crankcase gasses bottled up inside your motor which will either blow your dipstick out or blow your PCV valves out of their holes and make a big old oily mess. Tried it. Won't try it again! __________________ No truck :-(

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09-01-2002, 04:52 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	OK, not the first time I had a creak head idea. Thanks.



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