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Where should I have the PCV valve hooked up to? It's on a '66 Pontiac Catalina 389 with a 4-barrel and a edelbrrock intake. Right now it is hooked up to a manifold vacuum port.
PCV hook up?
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I was just making sure that it is o.k. there
PCv
Doc here
imp:
As 583 Said, Go directly from a manifold source For your PCV vacuum source.
Do Not TEE it off, Or to, anything else. The Valve pulls enough Vacuum so as to render anything else on that line ineffective,
(a Bad smell situation if it happens to be your power brake booster)
The other end of the PCV Valve goes into your Valve Cover or if so equipped, your oil filler tube (50's and 60's typical)
Be sure you have a positive breather Cap (S), and if so equipped, remove the road draft tube and plug the hole with a rubber expansion plug.
After you install the system, run it and check for any oil Gasket leaks, replace any leaking gaskets.
You should be gold.
Docimp:
Doc here
imp: As 583 Said, Go directly from a manifold source For your PCV vacuum source.
Do Not TEE it off, Or to, anything else. The Valve pulls enough Vacuum so as to render anything else on that line ineffective,
(a Bad smell situation if it happens to be your power brake booster)
The other end of the PCV Valve goes into your Valve Cover or if so equipped, your oil filler tube (50's and 60's typical)
Be sure you have a positive breather Cap (S), and if so equipped, remove the road draft tube and plug the hole with a rubber expansion plug.
After you install the system, run it and check for any oil Gasket leaks, replace any leaking gaskets.
You should be gold.
Doc
imp:
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115 Posts
Re: PCv
You've peaked my interest saying about the road draft. My '60 LeSabre has that. Are you saying I could get rid of the road draft tube and put in a breather cap on it that has a PCV in it?
The PCV on his goes to something on theblock right next to the distributor.docvette said:Doc here
The other end of the PCV Valve goes into your Valve Cover or if so equipped, your oil filler tube (50's and 60's typical)
Be sure you have a positive breather Cap (S), and if so equipped, remove the road draft tube and plug the hole with a rubber expansion plug.
Doc
You've peaked my interest saying about the road draft. My '60 LeSabre has that. Are you saying I could get rid of the road draft tube and put in a breather cap on it that has a PCV in it?
road draft..
Doc hereimp:
Yup...Get rid of the draft tube altogether...all you need is a PCV valve hooked up properly, and a positive vented cap...Plug the road draft hole with a rubber expansion plug..and "It's All Good"...
It will keep your engine and undercarriage much cleaner too..
Docimp:
Doc here
imp: Yup...Get rid of the draft tube altogether...all you need is a PCV valve hooked up properly, and a positive vented cap...Plug the road draft hole with a rubber expansion plug..and "It's All Good"...
It will keep your engine and undercarriage much cleaner too..
Doc
imp: hey doc could you expand on the positive breather cap? i didn't know there were different ones. i had a problem with oil leaking out of my breather cap and although i have gotten a few good ideas on it i'd like to get your opinion to.
its a 67 327 motor with a draft tube and an edelbrock intake that didn't have a filler tube so i replaced the drivers valve cover with one that has a breather and fill cap. the pcv goes from the draft tube to the carb. and i get oil leaking out of the breather. also there is no smoke from the motor. it runs good.
its a 67 327 motor with a draft tube and an edelbrock intake that didn't have a filler tube so i replaced the drivers valve cover with one that has a breather and fill cap. the pcv goes from the draft tube to the carb. and i get oil leaking out of the breather. also there is no smoke from the motor. it runs good.
Cap
Doc hereimp:
Yeah, Sure...The positive breather Cap is a Vented cap which Allows air flow to draw into and through the engine.
It allows a Positive air Flow through the engine to the PCV Valve. If it were Sealed, The Crankcase Would develop high Pressure and Blow out gaskets, and leak oil.
The Other type, Is a sealed cap (usually a cap with Two ears and a big gasket on the bottom that tightly seals to the oil filler or valve cover or a push~in plug type) It allows no breather option.... and Is usually used on Road draft (Non PCV systems) Type of systems as pressure is static and not an issue.
If your changing the system to a PCV (advisable) and abandoning and plugging the road draft, It is advisable to look into a set of covers, or check to see if your oil filler and PCV holes have Oil baffles in the valve covers (If that is where your cap and PCV install) This will Keep oil splash From happening.
Do you have aftermarker valve covers? with Duel Caps and baffles on your Valve Covers? You may want to plug the road draft with a rubber expansion plug, and move it to one of the filler caps (Eldebrock makes grommets that fit into a standard oil filler hole , down to PCV diameter size.) This layout seems to work the best.
Sounds like your Left Valve cover may need to be a Baffle type...if you have a vented cap...
So you might want to consider the arrangement I just suggested...Even though the PCV in the road draft hole is an equivalent Circuit..
A Set of nice Chrome Eldebrock Covers with baffles and duel fillers AND The grommet..is only about 50 bucks...Plus gaskets...
That should stop the oil splash...and If the Road draft is still open overboard, plugging it will keep your engine cleaner and the undercarriage and the PCV will be more effective.
Hope It Helps!
Docimp:
Doc here
imp: Yeah, Sure...The positive breather Cap is a Vented cap which Allows air flow to draw into and through the engine.
It allows a Positive air Flow through the engine to the PCV Valve. If it were Sealed, The Crankcase Would develop high Pressure and Blow out gaskets, and leak oil.
The Other type, Is a sealed cap (usually a cap with Two ears and a big gasket on the bottom that tightly seals to the oil filler or valve cover or a push~in plug type) It allows no breather option.... and Is usually used on Road draft (Non PCV systems) Type of systems as pressure is static and not an issue.
If your changing the system to a PCV (advisable) and abandoning and plugging the road draft, It is advisable to look into a set of covers, or check to see if your oil filler and PCV holes have Oil baffles in the valve covers (If that is where your cap and PCV install) This will Keep oil splash From happening.
Do you have aftermarker valve covers? with Duel Caps and baffles on your Valve Covers? You may want to plug the road draft with a rubber expansion plug, and move it to one of the filler caps (Eldebrock makes grommets that fit into a standard oil filler hole , down to PCV diameter size.) This layout seems to work the best.
Sounds like your Left Valve cover may need to be a Baffle type...if you have a vented cap...
So you might want to consider the arrangement I just suggested...Even though the PCV in the road draft hole is an equivalent Circuit..
A Set of nice Chrome Eldebrock Covers with baffles and duel fillers AND The grommet..is only about 50 bucks...Plus gaskets...
That should stop the oil splash...and If the Road draft is still open overboard, plugging it will keep your engine cleaner and the undercarriage and the PCV will be more effective.
Hope It Helps!
Doc
imp:
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Yup I agree with the previous posts lose the road draft tube the engine will develope much less acids and sludge its one of the best and cheapest upgrades to make
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170 Posts
I've got a related question:
My old 283 has so much blowby that it blew the PCV valve out of the valve cover again and again because with the old cast aluminum valve covers I only have one hole (no breather). So I just ran a straight hose to the air cleaner box. Seemed to work fine. Is there any good reason not to continue doing this when I install my fresh engine this month?
My old 283 has so much blowby that it blew the PCV valve out of the valve cover again and again because with the old cast aluminum valve covers I only have one hole (no breather). So I just ran a straight hose to the air cleaner box. Seemed to work fine. Is there any good reason not to continue doing this when I install my fresh engine this month?
straight hose?
Doc hereimp:
Do I understand correctly? you are running a hose from the valve cover (or other Crankcase vent) Straight into the Air Cleaner?
You should be finding your air-cleaner and canister full of oil, not to mention the induction system...especially if it has a lot of blow-by and back-pressure....
If that is how you do have it, chuck it...the PVC is among other things a Check Valve, Allowing vacuum into the crankcase to pull out vapors, but no oil should pass backwards...
Without it ,You will end up with a clogged air filter, dirty oily carb, and poor fuel economy to say the least...If it had the power to blow the valve out , imagine what it would do with oil in the line...
If you were getting the valve blowing out, you should set your system up as I said on the previous posts, because it sounds like your not getting positive ventilation through the crankcase, (developing back pressure from a closed system) due to lack of a breather cap..I would set your new mill up that way even if you have to spring for some custom covers...
Docimp:
Doc here
imp: Do I understand correctly? you are running a hose from the valve cover (or other Crankcase vent) Straight into the Air Cleaner?
You should be finding your air-cleaner and canister full of oil, not to mention the induction system...especially if it has a lot of blow-by and back-pressure....
If that is how you do have it, chuck it...the PVC is among other things a Check Valve, Allowing vacuum into the crankcase to pull out vapors, but no oil should pass backwards...
Without it ,You will end up with a clogged air filter, dirty oily carb, and poor fuel economy to say the least...If it had the power to blow the valve out , imagine what it would do with oil in the line...
If you were getting the valve blowing out, you should set your system up as I said on the previous posts, because it sounds like your not getting positive ventilation through the crankcase, (developing back pressure from a closed system) due to lack of a breather cap..I would set your new mill up that way even if you have to spring for some custom covers...
Doc
imp:
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170 Posts
Thanks Doc,
you're absolutely right. The filter is clogged with oil (very messy, bad gas mileage too, but ran OK otherwise), but I did not know what else to do. I did not like the visible smoke and oil vapours just spilling out everywhere uncontrolled, that's why I routed it into the air cleaner. The pressure overwhelmed the PCV any time I would accelerate hard. At least the car doesn't smoke at a stop light like I was on fire or something that way. There is no place for a breather because I have 60's cast aluminum Vette valve covers on it. One side had a hole while the other didn't. The excess pressure would just escape through a breather into the underhood area anyway.
Once I get the new engine in I will hood up a new PCV system to the Edelbrock carb like it's supposed to be... But do I really need a breather? I hate to carve up the classic valve covers, they look nice...
I didn't realize that the PCV valve keeps the oil where it's supposted to be, namely in the engine. I thought it was to prevent a carb backfire from passing into the crank case and possibly blowing off the oil pan in the process.
you're absolutely right. The filter is clogged with oil (very messy, bad gas mileage too, but ran OK otherwise), but I did not know what else to do. I did not like the visible smoke and oil vapours just spilling out everywhere uncontrolled, that's why I routed it into the air cleaner. The pressure overwhelmed the PCV any time I would accelerate hard. At least the car doesn't smoke at a stop light like I was on fire or something that way. There is no place for a breather because I have 60's cast aluminum Vette valve covers on it. One side had a hole while the other didn't. The excess pressure would just escape through a breather into the underhood area anyway.
Once I get the new engine in I will hood up a new PCV system to the Edelbrock carb like it's supposed to be... But do I really need a breather? I hate to carve up the classic valve covers, they look nice...
I didn't realize that the PCV valve keeps the oil where it's supposted to be, namely in the engine. I thought it was to prevent a carb backfire from passing into the crank case and possibly blowing off the oil pan in the process.
I think the road draft tube is of great use because you never have to worry about the underside of your car rusting!
Anyway...
Berliner,
You have a PCV valve in one of the aluminum covers? If they're the original style GM covers they shouldn't have any holes.
What I was wondering was if you have a 283 block, there should be a port behind the intake manifold about an inch or so in diameter. Yours may be plugged. If you remove that plug and install an original cap (I think they're still available from Year One) you will be able to route air into the engine from the air cleaner.
Anyway...
Berliner,
You have a PCV valve in one of the aluminum covers? If they're the original style GM covers they shouldn't have any holes.
What I was wondering was if you have a 283 block, there should be a port behind the intake manifold about an inch or so in diameter. Yours may be plugged. If you remove that plug and install an original cap (I think they're still available from Year One) you will be able to route air into the engine from the air cleaner.
Attachments
Breather
Doc hereimp:
That Road draft plug is a good option to drilling valve covers...
Do you have an Oil Filler PIPE on the front of the manifold? I'm thinking way back (don't know the year of yours) You can get a positive cap for those too..Looks like a "Slide on" or "Push down" Big cap that fits over the pipe, and has what looks like a filter inside of it. That should take care of the problem.
Docimp:
Doc here
imp: That Road draft plug is a good option to drilling valve covers...
Do you have an Oil Filler PIPE on the front of the manifold? I'm thinking way back (don't know the year of yours) You can get a positive cap for those too..Looks like a "Slide on" or "Push down" Big cap that fits over the pipe, and has what looks like a filter inside of it. That should take care of the problem.
Doc
imp: hey doc thanks for the info i know what your talking about now,i'm going to be doing the engine over and was hoping that the oil problem was not because of rings. i'm going to do a wet and dry compresion test and if all goes good i think just revamping the pcv system should cure the problem. thanks again:thumbup:
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170 Posts
Thats a great idea with that road draft tube fitting! I'll try to get one of those.
Someone cut a hole in one of the cast aluminum Vette covers. As it turns out not a bad thing because I need that hole to fill oil to the engine. The intake is a Performer so it has no oil filler pipe.
Someone cut a hole in one of the cast aluminum Vette covers. As it turns out not a bad thing because I need that hole to fill oil to the engine. The intake is a Performer so it has no oil filler pipe.
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