Profile Picture

PCV valve

Posted By cbass139 14 Years Ago
You don't have permission to rate!
Author
Message
cbass139
Posted 14 Years Ago
View Quick Profile
Supercharged

Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)

Group: Forum Members
Last Active: 13 Years Ago
Posts: 183, Visits: 898
Ted, I had done the search but did not see anything on what I was asking. I know I wanted to do a PCV and looked at what I needed and how to install it but I wanted to know a little more specifics of the actual valve and what I think I have found is that it creates the right amount of vacuum so as not to have a complete "leak" in the system. This tells me I can not run the gutless valve that came on the valley pan that I will be using. In all of the post you have there none has this information and thus my new post on a old subject. Thanks all



Sebastian

1958 F100 292

"Nothing is particularly hard if you divide it into small jobs."

"Chop your own wood, and it will warm you twice."

-Henry Ford

Ted
Posted 14 Years Ago
View Quick Profile
Co-Administrator

Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)

Group: Administrators
Last Active: 3 hours ago
Posts: 7.6K, Visits: 206.0K
Sebastian. Your are correct in that a PCV valve is a controlled vacuum leak. It’s metered so that the excess pressure from the crankcase can be reentered into the engine and combusted without leaning out the engine. Most new universal carbs are calibrated to include the PCV valve air flow as part of the idle circuit fuel mixture which means not using the PCV valve on a carburetor designed to use one will typically have a rich idle and possibly to the point that the plugs have difficulty in staying clean at low rpms. Whereas a road draft tube only works when the vehicle is moving, the PCV valve works as long as manifold vacuum is present. If you’re looking for specific flowrates, here’s the link and information from a past discussion..

http://forums.y-blocksforever.com/Topic22760-3-1.aspx

.

The road draft tube concept was effective but not without problems of which the more significant would be emission deposits into the atmosphere as well as placing a large amount of oil on the roadways. The oil on the roadways was not only deemed a hazard for driving but a concern to the environment as enough oil was being deposited to make its way into the soil and waterways. The incorporation of the Positive Crankase Ventilation (PCV) system in the early Sixties provided a simple and effective solution to the aforementioned problems. Most PCV valves will move approximately 3 cfm of air during normal driving and up to 6 cfm of air under higher load conditions. PCV valves are tailored for specific engine combinations (usually by cubic inch) and as such, care must be taken when retrofitting these valves to engines not originally equipped with PCV systems in that the sizing of the PCV valve must be considered. A side benefit to the PCV valve system is that the crankcase is under a light negative pressure during cruising which in turn minimizes oil leaks that would be present otherwise. Utilizing a road draft tube in conjunction with a PCV valve negates many of the benefits of using a PCV system.



Lorena, Texas (South of Waco)


cbass139
Posted 14 Years Ago
View Quick Profile
Supercharged

Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)Supercharged (183 reputation)

Group: Forum Members
Last Active: 13 Years Ago
Posts: 183, Visits: 898
Thanks Ted, that is awesome info.

1958 F100 292

"Nothing is particularly hard if you divide it into small jobs."

"Chop your own wood, and it will warm you twice."

-Henry Ford

MoonShadow
Posted 14 Years Ago
View Quick Profile
Supercharged

Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)Supercharged (7.8K reputation)

Group: Forum Members
Last Active: Yesterday
Posts: 4.6K, Visits: 39.4K
Ted,

When you dyno'd my new engine did you use my valley cover and the PCV valve thats in it? I bought that one on size to fit the hole and not by engine size. It could be too big and possibly be part of my erratic idle problems? Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Ted
Posted 14 Years Ago
View Quick Profile
Co-Administrator

Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)Co-Administrator (13.7K reputation)

Group: Administrators
Last Active: 3 hours ago
Posts: 7.6K, Visits: 206.0K
MoonShadow (7/27/2012)
Ted, When you dyno'd my new engine did you use my valley cover and the PCV valve thats in it? I bought that one on size to fit the hole and not by engine size. It could be too big and possibly be part of my erratic idle problems? Chuck

Chuck.  While your aluminum valley cover had a threaded hole at the back of it for a screw in style of PCV valve, it has a plug in the hole.  I did not find a PCV valve in your pile of parts.  The flat bowl Holley carb you provided did have a hose on it though but no PCV valve sticking on its end.  Your engine so far has been run without a PCV valve.   That’s simply due to the engine being run with the roots blower and not the McCulloch unit.  At this point, it’s been more expedient from a testing standpoint to not have PCV in place.  When I get the engine back on the dyno, I’ll fit a PCV valve to it so it’s tuned with the valve in place.

Lorena, Texas (South of Waco)




Reading This Topic


Site Meter