Oil Problem

[29Coupe348]

ok, heres the problem...this is the third time this has happened to me...im on the highway, at about 2800 rpm, and all of a sudden OIL, and lots of it all over the windshield, as far as i can see its comming out of the breather/oil fill tube...but the weird thing is it dosent happen all the time, im on the highway alot, and its only happened 3 times....i changed the pcv valve...what else????...a cracked ring, a ring hanging up, the wrong pcv valve????what????im using a pcv valve for a 64 409....thanks,mike

 

[Ronnie Russell]

Coupe, Have you got a road draft tube, or have you plugged it because you are using pcv valve? You cant have enough breathing, if you dont have road draft tube--get one. You can also try add-on breathers inthe valve covers. What ever it takes,,, you need to bleed off the crankcase pressure.

 

[29Coupe348]

i have the pcv where the road draft tube would go, and i really dont wanna put holes in my offy valve covers....i was thinking about nixing the pcv thing, and going back to a road draft tube.

 

[JimKwiatkowski]

I had the same problem blowing oil.I repaired my problem with a new oil filler cap.

 

[29Coupe348]

thats my next step, i have had the same cap on for the past 3 years...kool, thanks jim...,mike

 

[29Coupe348]

what PCV valve part# should i use?????

 

[rcurrier44]

I have seen severial engins that have drain problems ware you are running at a high enough RPM long enough that it is pimping more oil to the top of the heads than can drain back down. Eventualy it comes out the breather and gets all over the place.

 

[Mr Goodwrench]

I'm using a pcv valve for a 400 pontiac on my set up. the side that goes to the carb is 3/8" the side that goes to my oil fill tube is 1/2" thats pretty close to the way the factory was. I tried three of the stock ones, they all pulled my manifold vacume down from about 18.5 inches to 15 inches. carb wouldnt work right, and it ran like crap.

 

[29Coupe348]

kool, thanks....im using one from a 65 409.

 

[Ronnie Russell]

I have decided to comment on pcv valves.Sit down and get comfortable, this will take awhile. First , I decided to google pcv valves so I could have an accurate definition. Here it is ;;; The pcv valve is an emission control device that routes unburned crankcase blowby gases back into the intake manifold where they can be re-burned. Besides totally eliminating crankcase emissions as a source of pollution, the constant recirculation of air through the crankcase helps remove moisture which would otherwise cause sludge to form, thus the pcv valve extends the life of the oil and the engine. Who wrote this ridiculous stuff? Who believes this ridiculous stuff? True, it routes unburned blowby gasses back into intake manifold. what is blowby gasses? OIL MIST under pressure. I dont want to burn an oil mist, I want to burn gasoline. If I wanted to burn oil , I would buy a 2 cycle motor. Totally eliminating crankcase emissions? Nothing is total. Constant recirculation of air through crankcase? Guess I have overlooked that device. Where does that fresh air come from that is constantly recirculating in my crankcase? The intake manifold sucks the crankase pressure(oil mist) and impurities through the pcv valve and into combustion chamber. The pcv valve is supposed to open and close -controlled by engine vacuum. They all leak!!!! Even new , they leak. A controlled vacuum leak and sometimes an unconrolled vacuum leak. Ever tear down a pre-computer motor and see the pistons and valves covered in black carbon gunk? Think to yourself " My, these rings must be worn out, or My, these valve seals must be shot" Did you ever think what burning an oil mist for 50,000 miles does to the inside on an engine? You all know what oil does inside a combustion chamber. Back then we had real gasoline,with true octane, today we have junk gas. Do you really want to dillute your junk gas with oil mist? Forget about positive crankcase ventillation. Use a whole lot of negative crankcase ventillation. Burn gasoline , not oil and get rid of those vacuum leaks . Can anybody guess how I feel about pcv valves? Thanks for your patience and time.

 

[29Coupe348]

i had my heads off over the winter, and the tops of my pistons were black, now i know where it came from....so your saying you would reccomend a draft tube????...lol.

 

[Ronnie Russell]

Coupe Try a new breather cap , as JimKwi suggested .If you still oil up your windshield , try a road draft tube . Is nt the road draft tube a much bigger diamiter than the 1/4 in. opening in the base of the carb where the pcv attaches? Do what you gotta do to eliminate excessive crankcase pressure. If all attempts fail, then the rings must be worn badly .

 

[SS425HP]

PCV valves

Ronnie, quit beating around the bush and give us your true feelings on PCV valves.

 

[Fathead Racing]

Pcv.

I have ran a PCV valve on my 348 and now on my 409 with no negative effects so far. Runs and idles fine! Good for street engine I think. Road draft tube would work too I will guess, did for years. I prefer the PVC for my engine, just seems neater. I think PVC would eliminate more moister and keep the inside of the engine a little cleaner. This brings up food for thought. I guess if we really want to evacuate the crankcase of crap we could all get the Moroso setup that uses the exhaust collector to create a vacuum and reduces crankcase pressure.

 

[Ronnie Russell]

Dead on right , Ray... The evacuators plumbed into header collectors are the best for positive crankcase ventilation. Unfortunately , it is not practical for most street applications.

 

[walkerheaders]

these days the trend is moving toward vacuum pumps for crankcase evacuation. i have installed many of the Moroso kits on customer cars, all with impressive results. not only do they help to add power, they even help with oil leaks and ring sealing.
alot of racers dont stop to think that if you have 409 inches in the cylinders, then you also have 409 inches moving violently in the crankcase.
I always used the pan-evac system on my 470 BBC and never had a problem. but in a dragboat, the headers are behind you. at least i never saw any oil discoloration in the collectors? I always use 60W valvoline in the 470 (aluminum rods)
My 409 car uses the pcv on the rear carb and draws fresh air thru the air filter. i have turned this setup as high as 7200 with no blowby troubles. 6000-6500 rpm with my current combination. still no evidence of any trouble.
however, i may try some alternate ideas and see what happens.
even though Ronnie sugar coated his true feelings about PCV, he gave me some ideas.

 

[Ronnie Russell]

Bob, thanks for your comments. I , in no way , meant that pcv systems "causes" blowby problems. My point is very simply, The crankcase gasses and impurities that go out of an engine via road draft tube and onto the road or instead directed into the intake manifold. The loss of power ( if any) is not noticed by the driver. The gasses and impurities are mixed with fuel and burned. Cleaner for our enviroment for sure. I just prefer not to burn the crankcase gasses and impurities in the combustion chamber. Pcv systems cannot be a problem because this is the first discussion I have ever seen on the subject. Must be the weird way I look at things. The "trash" that used to go on the roadway, now goes into the combustion chambers" I just dont know any other way to look at it.

 

[Mr Goodwrench]

coupe I have a feeling you have excessive blow-by from a worn out engine, I believe a few posts earlier you made mention to that, please correct me if I'm wrong if that is the case neither a pcv valve or a draft tube will help you. your best bet I think would be a pcv valve on a closed system like the 409-425 used, in other words a sealed oil fill cap insted of the push on breather cap. the closed system has a hose coming from the oil fill tube and going back to the air cleaner. I had the same problem on my truck because alot of the miles I put on it are at WOT where there is no vacume to make a pcv valve work. I know what it's like to breathe that crankcase vapor, used to fill the inside of my truck up even made your clothes stink like you've been running an engine inside a closed garage.

 

[JimKwiatkowski]

Goodwrench,I use a sealed oil fill cap and breather caps on both valve covers with a PCV valve.I think 29 has 3x2 with small air cleaners,so he can't run a hose from the filler tube to the air cleaners.I think 29 needs to run a sealed oil fill tube and a road draft tube,if he does have a ring problem he should have alot smoke coming from his draft tube and no oil on his windshield,this will fix the oil on the windsheild till he can get a new short block.

 

[threeimpalas]

A road draft tube is going to get that A-bone all gunked up in place you don't want it to (ie; the underside of the car). Stick with a PCV setup.