Pcv ??

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Oldmanmopar said:
Larger Cam motors should not use them. Use a vacuum pump or an evac system.
Click to expand...

I would love to run a pump. Never could find one when I went looking. Evac systems allegedly will not work with mufflers.
 
"I have a set of M/T valve covers with a 1.5" ID hole. I found a 1.5" grommet with a 1" hole for a breather. Just nothing for the 3/4" PCV"

how thick is the valve cover where the grommet goes through?
Could try the dorman products web site, under pcv grommits, and look at the different sizes.
Good Luck.
 
OK. I am a bit confused between the two items...a pvc and a breather.

Neither of my valve covers have a hole for either.

I do have a breather - part # p4120446.

Should I buy 2 pvc and put one on each valve cover or one pvc and one breather ?

Neither of my brit cars had either though one had a stink pipe which came off the valve cover and was run under the car..maybe an early pvc valve :)

Thanks
Ian.
 
You will see all kinds of half-baked ideas on all kinds of car forums. There are very strange ideas that the oil and water vapors coming from the PCV to the carb are bad for gas economy, power, emissions, and other things. Yes, if you have bad or worn out rings, then way too much vapor WILL come to the carb and all those bad things will happen. But, a bad case of ring wear is no excuse for dumping all kinds of crap into the air we need to breathe or the water we need to drink.

So, use the PCV and keep it maintained (they're cheap to replace!). Somebody will have the correctly dimensioned grommet, just keep looking - and look hard, please. Almost everyone on this thread has given you every reason why you NEED to have a PCV. Your car will at the least smell better :angel5:
 
straightlinespeed said:
I have a set of M/T valve covers with a 1.5" ID hole. I found a 1.5" grommet with a 1" hole for a breather. Just nothing for the 3/4" PCV
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Holley p/n 241-214 has two grommets with a 3/4" PCV hole for the M/T valve covers.
 
straightlinespeed said:
I eliminated my PCV valve but kept my breathers. Im wondering how many of you are actually running a PCV? Are they required? Pros/Cons
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They work best when the engine/cam provides decent manifold vacuum at idle. The manifold vacuum holds the pintle so the air flow is most restricted. Low vacuum at idle means that ointle sits lower and more comes into the carb. This can be a tuning headache, but that's hotrodding...
 
grassy said:
OK. I am a bit confused between the two items...a pvc and a breather.

Neither of my valve covers have a hole for either.

I do have a breather - part # p4120446.

Should I buy 2 pvc and put one on each valve cover or one pvc and one breather ?

Neither of my brit cars had either though one had a stink pipe which came off the valve cover and was run under the car..maybe an early pvc valve :)

Thanks
Ian.
Click to expand...


YOu want a PCV on one side, breather on the other.
 
TrailBeast said:
Blow-by gases mainly consist of contaminants such as hydrocarbons (unburned fuel), carbon dioxide or water vapor, all of which are harmful to the engine crankcase. The quantity of blow-by gas in the crankcase can be several times that of the concentration of hydrocarbons in the intake manifold. Simply venting these gases to the atmosphere increases air pollution. Although, trapping the blow-by gases in the crankcase allows the contaminants to condense out of air and accumulate therein over time. Condensed contaminants form corrosive acids and sludge in the interior of the crankcase that dilutes the lubricating oil. This decreases the ability of the oil to lubricate the cylinder and crankshaft. Degraded oil that fails to properly lubricate the crankcase components (e.g. the crankshaft and connecting rods) can be a factor in poor engine performance. Inadequate crankcase lubrication contributes to unnecessary wear on the piston rings which simultaneously reduces the quality of the seal between the combustion chamber and the crankcase. As the engine ages, the gaps between the piston rings and cylinder walls increase resulting in larger quantities of blow-by gases entering the crankcase. Too much blow-by gases entering the crankcase can cause power loss and even engine failure. Moreover, condensed water in the blow-by gases can cause engine parts to rust. Hence, crankcase ventilation systems were developed to remedy the existence of blow-by gases in the crankcase. In general, crankcase ventilation systems expel blow-by gases out of a positive crankcase ventilation (PCV) valve and into the intake manifold to be reburned.
Click to expand...
DING DING DING DING DING!!!

Why sacrifice your motor for NO performance gain whatsoever?
 
yall know if there's a -AN style PCV valve available? screw-in type to a weldable bung on a valve cover?
 
grassy said:
OK. I am a bit confused between the two items...a pvc and a breather.

Neither of my valve covers have a hole for either.

I do have a breather - part # p4120446.

Should I buy 2 pvc and put one on each valve cover or one pvc and one breather ?

Neither of my brit cars had either though one had a stink pipe which came off the valve cover and was run under the car..maybe an early pvc valve :)

Thanks


Ian.
Click to expand...

The breather is there, because manifold vacuum dissappears as the throttle is opened and at some point the blowby exceeds what the pcv can handle, so the breather allows the excess blow-by to be vented, usually to the air-cleaner,, or in some cases just vent to the engine compartment or to a "stink tube", called a 'road-vent' tube.

No vent, with only pcv, would likely cause seal leaks, or oil pushing out the dipstick tube, because of excess crankase pressure at high rpm..
 
Anyone know of a vendor that sells the grommets that fit in where the oil is poured in ? I have both now but do not want to drill holes...
 
I run a pcv on my race car. I didn't won't to drill and weld in the bungs on my ceramic headers for evac hoses to run from the valve cover. so the way I overcame, was to install an in line filter between the pcv and carb. jegs and moroso both offer them. its just a glass, or clear plastic, housing. it has a small filter inside that you can view, and also has a drain valve on the bottom, for when it gets full. you get the best of both worlds. positive ring seal by using the pcv, a clean engine bay free of oil mist, and none of the oil, carbon, or water vapors back inside the intake charge. works great for me.
 
green1 said:
So diluting your intake charge with exhaust gases, that don't burn, is better?
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Maybe you're thinking of the EGR valve which does inject exhaust gases into the intake stream - to cool the burn and reduce specific pollutants. A PCV allows the light evaporated gases (which DO burn) from the crankcase to enter the intake stream. The PCV keeps these lighter evaporation products from washing oil down from the cylinders.

PCV = always good (at least s for stock or moderate builds). EGR, only if your engine needs it.
 
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