....... edit.....PCV....... I have used the search button and didn't come to a conclusive answer. I have two later model 350's, they will have intakes with the oil fill tube in front. One set of valve covers are early staggerd corvette finned pairs the other are earlier call custom straight 9 finned pairs. I want to know if the oil fill tube is enough to vent the motor without it blowing oil all over the place? These motors do not have road draft tubes or the pvc in place where that road draft tube goes.
No, if it doesn't have a road draft tube you will want to hook up a PCV valve. Some drill the manifold and build a baffle so it doesn't suck oil. If you put it in the back it isn't too noticable.
I've ran motors with just the vented oil cap and it will work. When I got to mydestination i would wipe off the oil vapor. A rag tied just below the oil cap. However this is not a good idea. Just said it will work. And if you romp on it expect oil everywhere
You can install some breathers in the side of the valve covers or get some valve covers with the oil fill holes in them. Then use a non-vented cap on the oil fill tube and install a nipple in the tube. Run a hose to the carb base and your done.
id put the pcv in the filler tube, no issues putting it there as long as you put a baffle inside the tube of some sorts.... but do like the idea of the intake manifold better so you can put negative pressure and pull clean air through the oil filler tube.
I'm just wondering if you know that there are an ass load of threads on this subject, why didn't you read them?
If you want minimal oil leaks, you will plug all the openings, find a good spot to plug one in (even if you have to drill one), and run a PCV routed to the base of the carb. If you have too much blowby for this method, revert back to the red rag!!! K
I looked at alot of them. My direct question was if the fill tube is the only way to vent is that enough? I didn't see that answer. Awhile back I made a comment on another thread about the road draft tube and you responded with a great explanation of how it actually creates a vaccuum and pulls air through the oil fill tube.
And that is exactly how a PCV system works. You need more than just a "vent" You need to pull air through the engine to remove acids and water vapor that creates sludge. I know I have written a variation of that sentence more than a few times over the years I bet if you read them carefully you would find that answer. I'm not trying to break your balls but there is a hell of a lot of info on this subject on the HAMB. Yeah I have responded to most of them. One of the most misunderstood subjects that keeps coming up over and over again.
With your explanation I know how it works, I just wanted to know it it is doable to run it with out the pcv, using only the vent. I have come to the conclusion, that I shouldn't do it. I have cool valve covers I don't want to cut and the tri power intake is a SBC Fenton that I really didn't want to tap. I am just going to tap a hole in the back side of the intake and run a pcv valve with the line going into the base of the rear carb. It should work well, and turn the fill tube from a "vent" to a place to allow the air to actually get into the engine. Joe
PCV on the back side of the drivers valve cover stefs breather canister vent to back side of passengers valve cover. for a cleaner smoother valve cover that keeps snot and oil out of engine compartment! By profleetline at 2011-03-28 By profleetline at 2011-04-13 By profleetline at 2011-03-28
Don't try to be fancy using a small PCV valve and a filter under the intake like I did at first with my hotrod engine. You will not like the oil consumption results or the engine startup cloud of blue smoke. I ended up putting a PCV valve in the valve cover anyways and I am still using a dirt car type filter on the intake oil fill tube. Made a major positive difference.
That is the right way to do it for running on the street and not having an oil mess on the valve covers and engine compartment. Putting a baffle on the inside of the intake is a pretty good idea too. Just something to deflect any oil or oil spray that might directly hit the pcv valve.
Regarding the baffle, are you just talking about a sheet metal screen that deflects the oil from directly going into the valve. Kind of like what valve covers should have when they have holes in them?
my friends A has the oil fill tube with the pcv screwed in about 1/2 way down, a vent cap and it still mists the window and firewall. if you have have a fenton intake that's worth money I would either sell the fenton and buy a cheaper intake to tap or find an older motor with the early road draft set-up.........just my .02 and yes the baffle is just to keep oil from entering the pcv.
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