Im building a SBC from the ground up. Its got almost everything new inside, but I've realized I have a problem. I'm using an old Edelbrock intake manifold with an oil fill tube in the front. I have cal-custom finned valve covers with no holes for vents or PCV valve. I'm using a block from 1970 that has no provision for a draft tube. What can i do to have enough crankcase ventialtion without sacraficing the looks of an older small block? I've seen in small books the idea of a vent in the oil pan? Or maybe hiding a PCV valve?
You could run an electric fuel pump, and use the old fuel pump hole. You can hollow it out and get big air flow into and out of the crankcase. I've seen this done, usually with a hose or pipe going up from the hole.
You can drill the intake for one behind the carb. Edelbrock makes one with the oil fill tube and the hole already drilled, but I don't see why you couldn't drill it yourself. I ran this same setup for years.
Best advice. Do a search, if PCV is too short try key words like "positive" or "ventilation"...lots of threads on this.
My fuel pump block off plate that I tapped and ran my pcv breather line to it for crankcase ventilation....
Change to the early Corvette filler tube:http://www.ebay.com/itm/Corvette-Oi...65|Model:Corvette&hash=item417489b7e5&vxp=mtr Install the matching PCV and you are gold.
There can be significant engine life benefits with PCV. To realize the benefits of crankcase ventilation there should be airflow from the corners or ends of the engine through the engine, just like the road draft system had. Providing a Vent for blowby in order to reduce crankcse pressure is only half the deal for an engine I want to run well and last thousands of miles. http://www.consumerreports.org/cro/2012/12/the-black-death-of-sludge/index.htm
One of the magazines just had an article on this, should be on the stands, I forget which one. I think they drilled a hole in the side of the valve cover, though, you may not want to do that on a nice set of Cal Customs.
Go ya one better if you want to get a little more aggresive. Use the mechanical fuel pump AS a vacuum pump. Plumb the suck side into the file tube, valve cover, or drill and tap the a hole throught the manifold into the lifter valley (Buick 400/430/455)have a PCV grommet this way behind the carb pad. Plumb the the out/exh side of the fuel (now vacuum pump)into a puke can/tank. I used the original Moon tank on the front of our '56 as the vent/puke tank. We have also used the mechanical fuel pump as a vacuum source for a power brake resevoir on power brake cars with big camshafts. This is the "pan evac" system on our '56. I tried to make it look like an old school fuel system at first glance. You'll notice however that the lines from the fuel block are plumbed into the bottom half of the tunnel ram where they suck "draggon breath" from the lifter valley. The Moon breathers on the valve covers are there for looks. I drilled and tapped the valve covers for 3/4 pipe plugs that are hidden by the Moon breathers. If we need additional breathing capability, I can drill the center of the pipe plugs out, or simply remove one or both of them.
If you use the carb as a vacuum source, put a clear fuel filter between the carb and the pcv valve to seperate the oil from the crankcase "breath", that way the engine is not ingesting oil (or at least a whole bunch less)into the intake manifol.
If you drill the intake behind the carb use one of the lifter vally baffles so it wont suck spashing oil from the lifter vally.
As the fuel pump boss area can be used as I the photo, you can also use the "top" bolt on the front side of the timing chain area can also be used so that a mechanical pump can still be used. We have done both ways since the 70's, good luck.
Here are a couple other pics of my intake and such. I have a fill tube in the back of my my Scorpion intake with a breather in it. Then ran pcv off back of carb down to fuel block off plate.
I drill and tap a 3/8 NPT into the back of the intake and build a baffle on the underside of the intake. Then, I use a PV1045 PCV and connect it to the back of the carb. Used this on engines over the last 12 years with no problems
Subscribed. I have been looking for a solution to modify some corvette valve covers without hosing them up. I just stumbled on one more creative way this evening from a fellow named Van Pershing in Tucson AZ, You have to modify the valve cover, but it is very well hidden. The process is well photographed and described on thisweb page http://www.persh.org/pickup/ValveCovers.htm
Verno30, For the baffle you fabricate, could you give some detail? I have heard some folks use steel wool. I am interested in what you use, and how you attach it. The valve cover solution I referenced above is clean, but I like the look of yours without disturbing the valve covers.
Thanks Saltflats, I missed that the first go around. Since I posted, I have been searching PCV posts and found a cool tech one from Tommy that describes the PCV operation quite well along with some parts photos. PCV valve for road draft tube block SBC http://www.jalopyjournal.com/forum/showthread.php?t=151629 The fill tube on a 66 Corvette has a threaded bung on it for a pcv # GM put them into the fill tube on some sbc right from the factory. You can buy a chrome aftermarket one from Chevy2Only: http://www.parts123.com/parts123/yb....Z5Z5Z50000132A They also have them in black if you don't want bling. # Pcv Tech (by Tommy) http://www.jalopyjournal.com/forum/showthread.php?t=61376&highlight=tommy+pcv+system flamed abone wanted pix...posts 13, 19 PCV time again!! http://www.jalopyjournal.com/forum/showthread.php?t=60593&page=1&pp=20
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