I run an early 70's 350 small block chevy and am having a problem of oil out throught the valve cover breather. The other valve cover holds the PVC valve which i have cleaned and found unobstructed. There is also suction at the end of the pcv and hose up into the carb. All clear. The two main oil return holes in the heads are huge and unobstructed. I cant quite figure out what to attack next. Valve adjustment? Any ideas. Can I just close the hole and would this cause it to push out somewhere else. I really would like to fix this. There is a baffel under the breather and I have even inserted another which has even more blocking capability. No luck. It just seems to be an area of pressure releif. Help.
70's small block = closed crankcase ventilation = 1 connection from crankcase to inlet manifold vacuum source and 1 connection to air filter. Your crankcase connection in this case would be the valve cover.
I agree with Hatch; this sounds like blow-by. I have this problem like a mother on my daily (302 Ford with 200,000+ miles). Converting to a closed system will suck the oil vapors down the carb instead of dumping them into your engine compartment. Ed PS - I've recently added STP's Engine Treatment oil additive. The stuff is the consistency of rice syrup or molasses. It really thickens the oil up. I've noticed the engine runs quieter with it and hopefully it's doing something to minimize blow-by. As an added side benefit, the oil pan gasket doesn't seem to be leaking as much.
You can't close up the system--if it's building pressure, it'll find a way out someplace else. Either reduce the blowby (oil weight, rebuild, etc) or find a way to direct someplace cleaner, like back into the air cleaner or a catch can.
Get some clear 3/8" hose from Home Depot,& test-run it from the PCV valve to the base of the carb(or manifold) & see what happens. I had a crankcase vent problem,& discovered the baffle under the PCV valve was tweaked a bit,& saw oil in the clear hose.
I have the same setup and the same problem. It has been suggested to run a hose from the breather into the carb air cleaner. Instead I've just run a hose from the breather down beside the oil pan. No more oil out through my hood louvers onto the windshield. Works for me......
I had an old 351M motor in a truck, the rings were toast and the blow by would put oil in the air cleaner, had to wipe it out each time I checked the oil. The motor was junk, but wouldnt die. When I did a valve job on it in shop class it just made the rings suck that much more oil past them 17 and dumb and no money.
I have this problem on my 400 , BUT compression is above 150# NO oil smoke even when i get on it HARD, I've determined it is a valve blow by, and hopefully will be taken care of when i put on the Darts JM2C
Oil foul situation?????? Just like Dr J said before; put the damned hose back up to the air cleaner. Why is it that some people, when told a fact, have to counter it with theory bullshit without trying it? The system, as originally designed, wont foul the spark plugs. If the motor had that much blow-by, or valve guide wear, it would be pumping/burning a quart of oil every week, and would already be fouling the spark plugs. Of Course, in that case, all of this wondering (what to do?) would be moot. In the normal situation, as the breather system was designed originally, when the oil vapor reaches the breather thats been put on there, in place of the breather hose to the air cleaner, it (the oil vapor) condenses, from a vapor state to a liquid state and accumulates on the outside of your motor. If you put the damned hose back on, when the vapor enters the hose through a pcv, the pcv body and the hose being cooler than the inside of the valve cover, then the oil vapor will condense. Since its uphill to the air cleaner, the oil will simply collect (in droplet form) on the inside walls of the hose and drip back down through the pcv into the valve cover. Very little oil will ever get up/into to the air cleaner.
Another option is to put a tube into the exhaust collector and suck the crankcase fumes out that way. It is pretty common on race cars. I've never liked the PCV setup simply because they always put a little oil down the intake, and if the rings are worn out it pumps shit down the intake. That said, one way or another you always need at least a neutral/negative crankcase pressure.
Wow, you're ANGRY! So, I got a 68 327. Put a breather on the front fill tube, and a PCV in the pass. side of my Cal Custom finned V/C's. The hose then goes to the front of my Edelbrock 4V. Don't seem to get too much suction at idle at the oil tube, however. I get the oil coming out mostly at highway speeds. Could I be creating a vaccum on the breather since it's a hoodless "A", with air passing over? I have been meaning to try to rig up a shield for the breather to test this theory. Obviously there are no baffles in the tube. Any other thoughts?
Many 40 and 50's engines had a road draft tube at the back of the block. This hung down into the air stream under the car. The motion of the car through the air would cause a low pressure area behind the pipe into which the vaporous nasties from inside the crankcase would flow. If possible I would either shield the breather, of maybe the lower the pipe it sits on out of the airstream, couldn't hurt. The side benefit of the oily mist under the car was that when driven on dusty dirt roads, it deposited a nearly impenatrable layer or free rust preventative on the bottom of the car.
I have the same problem on my 30 Ford with 350 and a tunnel ram, no hood. I am using one of those K&N breathers and when ever I will be on the hiway for an extended time I tie a red rag around the base of the breather, looks bad but works. Around town it is no problem If I had an air cleaner I would route a hose back into the cleaner but I have velocity stacks and there is no good place without looking bad. dave
3. It is pretty hard to put a hose back into a Hilborn style scoop. It aint stockers we run here.[/QUOTE] Exactly. Thanks PLYM 46, I don't have a road draft system on this motor, though. Z
One thing I'd try is a different PCV valve. PCV valves are designed to reduce the air flow during high vacuum conditions...idle and cruising. It's possible that your engine needs a PCV valve with more air flow at cruising high vacuum conditions. The factory moved the breather into the air cleaner with a hose to pick up the excessive fumes during a heavy load when the PCV valve can't keep up with the blow by. If everything is right that won't happen at cruising speeds.
My Tone? My, my, my....... You, can save your lecturing for the classroom. 1) YOu asked for the advice, then you pushed that 'oil foul' thingie twice, must have been a point there, but when it became obvious that you were talkin' shit about something you don't know shit about, then you jump back on me 'cause I'm ONLY a grenade inspector? It has to be a first class moron to evaluate advice, based on a thumb-suckin' lable. Save your fuckin' lables for the dim-wits. 2) So, now I got the picture. Your explain'in' ( pretty hard to put a hose back into a Hilborn style scoop) helps me fathom the depth of your knowledge. Consultation with a mechanic can give you the best of both worlds.... ............. try it. 3) Leave my *wife out of it; *presumed 4) A SBC with a Hilborn style scoop? What's that? (style) Does a Hilborn style make it somehow better than a stocker (in your mind)? Besides, now, your ride is sounding more more like a 'street' than a 'traditional'. I'm Not being a 'labler' myself, just wonder what you're all high and mighty about when you say, "It aint stockers we run here" 5) I don't have anything against scoops. Ani-que, modern, billett, rat, traditional .......... , shit-fire, any style. But you can still run a hose up there to any of them if you want to get rid of the oil mist. Not hard at all. If you can't figure it out, call a mechanic.............. 6) I come on the HAMB almost every day to enjoy the bullshit. 7) My tone? Your tone? my, my, my.
, Ever notice the sheild on the flatty Ford V8 breather's ? might be .... actually I have had some wind suction issues on my open to the road motors, but it is VERY minimal.I think B29's blow by tube is probably the best first try step, you can always go on after that , I'll try it , as my motor has NO plug fouling or smoke at all.I can always move on to the next most likely thing after that,on my motor I CAN run a tube to the air cleaner.
6) I come on the HAMB almost every day to enjoy the bullshit. And thank you...it is bullshit you have delivered. All I wanted was good natured advice.
A "trick" that local racers used on tired old engines running in the "hobby stock" or "cruiser" classes was to stuff the breather with brass screen to prevent the oil from actually coming out the breather - guess it collects on the brass screen and drips back in, the brass being soft if it ever got sucked into the engine it would be mashed up by the pump and not destroy things too bad... more tricks: - extended breather tubes (see circle track valve covers tall breather tubes) - Run no PCV valve and a hose through a cheap fuel filter then into the intake vacuum line - 50W engine oil - Clean the rings with the "seafoam" trick (heard it works, never tried - pour 1/2 can through carb until it smokes hard, then use oil can to squirt cylinders full with the other 1/2 can, let sit overnight with plugs in, pull plugs, crank out the excess, start engine and drive it like you stole it...) - re-ring the engine to reduce blowby - kits are under $80 and if it's a real hot rod the engine can be out in an hour or so... Post some detailed pics of the current setup.
Make sure that you breather is not directly over a rocker,the push rod may skirting in the bottom of the breather.
Hey Mike I have been to your shop numerous times. I lived in Mckinney up until LY Now in Ohio. Good to hear from the Sachse Rod Shop!
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