PCV, advantage or not?

[Bub Whitaker]

Originally Posted by junior barns

what does PCV stand for?

Positive Crankshaft Ventilation, It's a hose from an intake vacume sorce, carb or intake manifold, that draws air thru the engine to remove water and fumes. What they are discussing here is using this vacume source to create a vacume in the pan by sealing off all breathers to aid ring seal, if it's good enough...

[trmnatr]

Originally Posted by Bub Whitaker

Positive Crankshaft Ventilation, It's a hose from an intake vacume sorce, carb or intake manifold, that draws air thru the engine to remove water and fumes. What they are discussing here is using this vacume source to create a vacume in the pan by sealing off all breathers to aid ring seal, if it's good enough...

Bub,

How about running one valve cover with two holes and one with one hole

In the one with one hole you will have a header e-vac, on the cover with 2 holes you will have a header e-vac and a pcv valve + header e-vac through intake valley with baffle so it doesnt suck oil.

Wouldnt this give you good breathing if you couldnt run a vacuum pump as the pcv valve would work great at idle then close WOT BUT @ WOT the header e-vac would be working by pulling vacuum in the heads and lifter valley ??

How much better would a header e-vac work if you had one in the intake too ? With the header e-vac in the valve cover it has to pull from limited area (pushrod holes, drain back holes etc) and as we know oil can get up in the heads and not drain quick so maybe we also cant pull enough vacuum quick enough through drain holes etc. This way with 3 header e-vac's

Any Thoughts ??

[Ian Hill]

...and how about on a stocker. i don't know about NHRA, but in IHRA we can not run header evac, is there anyway of hooking up the carburator metering block tube that creates vacuum throughout the rpm range to the pcv to create vacuum even at WOT.

Ian

[trmnatr]

Originally Posted by Ian Hill

...and how about on a stocker. i don't know about NHRA, but in IHRA we can not run header evac, is there anyway of hooking up the carburator metering block tube that creates vacuum throughout the rpm range to the pcv to create vacuum even at WOT.

Ian

Sorry about that, my question wasnt about stocker(s). You guys have some tuff challanges in Stock

[Bub Whitaker]

Originally Posted by trmnatr

Bub,

How about running one valve cover with two holes and one with one hole

In the one with one hole you will have a header e-vac, on the cover with 2 holes you will have a header e-vac and a pcv valve + header e-vac through intake valley with baffle so it doesnt suck oil.

Wouldnt this give you good breathing if you couldnt run a vacuum pump as the pcv valve would work great at idle then close WOT BUT @ WOT the header e-vac would be working by pulling vacuum in the heads and lifter valley ??

How much better would a header e-vac work if you had one in the intake too ? With the header e-vac in the valve cover it has to pull from limited area (pushrod holes, drain back holes etc) and as we know oil can get up in the heads and not drain quick so maybe we also cant pull enough vacuum quick enough through drain holes etc. This way with 3 header e-vac's

Any Thoughts ??

What you want here is what I use on Superstock engines, Delco FB101 breathers that have 5/8 hose nipples and I bore the top 3/4 for a brake booster valve that seals when not being sucked on with hoses T'd to the PCV port on the carb. Don't do this to an intake runner as it will screw up that cylinder. EGR valves on tubes in the collectors at 45 degree cut to draw when exh velocity gets up to take over when intake vacume diminishes. the EGR valves on the collectors also seal the same way as the brake booster valves so there is constant vacume in the crankcase...

[Bub Whitaker]

Originally Posted by Ian Hill

...and how about on a stocker. i don't know about NHRA, but in IHRA we can not run header evac, is there anyway of hooking up the carburator metering block tube that creates vacuum throughout the rpm range to the pcv to create vacuum even at WOT.

Ian

All you can do on stockers is intake vacume. If your ring seal is real good than you can use brake booster valves that seal when vacume diminishes and it will maintain nicely.. If ring seal is so so, use PCV valves as they don't seal as well and won't build as much pressure. The main thing here is you don't want any pressure in the crankcase as it will unload the rings and you will loose power, or blow oil out of every orfice that ain't up to the task. which leads me to another important step that you have to pay attention to... You can't have any leaks, you cant build vacumn in the crankcase if it don't seal!!! Test for leaks by slightly pressurizing the crankcase and listen, squirt with soapy water and seal them all up...

[James Perrone]

Bub
SHHHH!
No more Top Secret Stuff

[Bub Whitaker]

Originally Posted by James Perrone

Bub
SHHHH!
No more Top Secret Stuff

Sorry,,, erase erace erace, delete

[scorpa]

Originally Posted by Bub Whitaker

EGR valves on tubes in the collectors at 45 degree cut to draw when exh velocity gets up to take over when intake vacume diminishes. the EGR valves on the collectors also seal the same way as the brake booster valves so there is constant vacume in the crankcase...

I think you mean....air injection check valves.
A EGR valve injects exhaust gases into the intake as an inert gas to control NOX. Cool the combustion mixture.
Smog test guy (CA) so I had to answer.

[Jeff Lee]

Just to clarify, any pan-e-vac or even open tubes hanging in the wind are NOT legal for Stock Eliminator.
A pan-e-vac is allowable in Superstock and is more effective than a PCV system.