Crankcase vent
Thread Starter
Heel & Toe
Joined: Jan 2006
Posts: 15
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From: Wyoming
Crankcase vent
My 68' is misting oil out of the filler/vent neck. This happens at RPM's over 3000 (about).
I've assumed that this is due to piston ring blow by as the car only has about 3000 miles on its rebuild with molly rings.
I understand that in 68' the 327/350hp did not have a "closed possitive" or PCV style venting.....BUT, I really need some way of scavenging this oil mist off the vent. It's getting oil all over my pretty motor and engine compartment.
I do not want to update the system to a PCV because it would require cutting a hole in my valve covers... sooooo, Can I just run some vacuum from the manifold to the vent cap?
Any ideas? Anyone else have that problem?
I've assumed that this is due to piston ring blow by as the car only has about 3000 miles on its rebuild with molly rings.
I understand that in 68' the 327/350hp did not have a "closed possitive" or PCV style venting.....BUT, I really need some way of scavenging this oil mist off the vent. It's getting oil all over my pretty motor and engine compartment.
I do not want to update the system to a PCV because it would require cutting a hole in my valve covers... sooooo, Can I just run some vacuum from the manifold to the vent cap?
Any ideas? Anyone else have that problem?
Thread Starter
Heel & Toe
Joined: Jan 2006
Posts: 15
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From: Wyoming
They say "327 Turbofire" in a glazed plaque in the middle. No holes or vents in them at all.
My 68 era Chiltons does point out that there is a difference between the PCV or Closed system vs. the possitive system. I'm assuming that factory stock is to simply let any vapor build up to simply vent free up the oil neck... but with more pressure coming out, this is just not gonna work. I've got a Ralley on labor day and have 250 miles to get there, she's gonna be covered in oil and I'll have hours of cleaning to do for the show-n-shine....sux!
My 68 era Chiltons does point out that there is a difference between the PCV or Closed system vs. the possitive system. I'm assuming that factory stock is to simply let any vapor build up to simply vent free up the oil neck... but with more pressure coming out, this is just not gonna work. I've got a Ralley on labor day and have 250 miles to get there, she's gonna be covered in oil and I'll have hours of cleaning to do for the show-n-shine....sux!
Le Mans Master
Joined: Jan 2006
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by Wyoming68
They say "327 Turbofire" in a glazed plaque in the middle. No holes or vents in them at all.
My 68 era Chiltons does point out that there is a difference between the PCV or Closed system vs. the possitive system. I'm assuming that factory stock is to simply let any vapor build up to simply vent free up the oil neck... but with more pressure coming out, this is just not gonna work. I've got a Ralley on labor day and have 250 miles to get there, she's gonna be covered in oil and I'll have hours of cleaning to do for the show-n-shine....sux!
My 68 era Chiltons does point out that there is a difference between the PCV or Closed system vs. the possitive system. I'm assuming that factory stock is to simply let any vapor build up to simply vent free up the oil neck... but with more pressure coming out, this is just not gonna work. I've got a Ralley on labor day and have 250 miles to get there, she's gonna be covered in oil and I'll have hours of cleaning to do for the show-n-shine....sux!
well something isn't right, th 68 was the fist year for the newer style PVC, both valve covers should have outlets, the pass side goes to the air cleaner base the drivers side goes to a fitting on the carb
since you don't have this, that is part of your problem.
someone swapped the valve covers at some point on your ride, and stuck some stickers on em, or more likely they came off of another 327 equipped Chevy, like a camaro which used the older style PVC system using the canister under the intake, and the hoses connecting the oil fill tube.
should be like this
Tim
Tim
Last edited by sweethence; Aug 9, 2006 at 12:38 PM.
Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by Wyoming68
Nope doesn't look like that at all... that's what a "closed possitive system" looks like. Not what my Chiltons shows for it in 68 either. How do I post a picture of my engine????
Much as i love the old Chilton's on my shelf, in this case is not accurate, but that is not surprising for the PVC system. you can referencing the factory manual, but suffice it to say the pics above are how is should look as from the factory.
to post a pic, you need a web hosting like photobucket then simply paste in the link into your post, or email it to me if you like and ill put it up
tim
Last edited by sweethence; Aug 9, 2006 at 12:36 PM.
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
You may have an earlier (replacement) engine with the crankcase vent at the back driver's side of the engine attached to the air cleaner base. If yes you can use the 1967 oil fill tube with the integrated PCV valve. It connects to a vacuum source on the carb. In this case a Holley.
Here is the crankcase vent with an Edelbrock.
And the PCV with the Edelbrock.
Here is the crankcase vent with an Edelbrock.
And the PCV with the Edelbrock.
Last edited by Paul L; Aug 9, 2006 at 12:55 PM.
Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by paul67
You may have an earlier (replacement) engine with the crankcase vent at the back driver's side of the engine attached to the air cleaner base. If yes you can use the 1967 oil fill tube with the integrated PCV valve. It connects to a vacuum source on the carb. In this case a Holley.
Here is the crankcase vent with an Edelbrock.
And the PCV with the Edelbrock.
Here is the crankcase vent with an Edelbrock.
And the PCV with the Edelbrock.
W68 quick question, i am curious, do you have a hose coming from the back of the engine near the distributor connected to a conical shaped fitting with a bolt on the top?
Tiom
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Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by Wyoming68
It's not a replacement, the numbers match.
OK how about the hose from the back of the block then, if you don't have it which i suspect you don't with the original motor, that i would say some one modified your engine with GM parts for personal taste or necessity, or who knows,
you need to either do what Paul says and get that 67 oil fill tube ( the camaro catalogs from the same year will also supply them), or get the vale covers with the PVC holes, the grommets, and the hoses to connect.
is your air cleaner original?
is it is, it will have the fitting to connect the PVC hose from the pass side valve cover
tim
Thread Starter
Heel & Toe
Joined: Jan 2006
Posts: 15
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From: Wyoming
No, I don't have the hose your talking about. It has had the manifold changed to a Holly Dominator.
It does have a breather cap on the fill neck that has a hose nipple with a pcv valve in a hose between there and the full port vacuum on the carb.
I don't know what the original air cleaner looks like. Mine is just a chrome dish like yours.
It does have a breather cap on the fill neck that has a hose nipple with a pcv valve in a hose between there and the full port vacuum on the carb.
I don't know what the original air cleaner looks like. Mine is just a chrome dish like yours.
Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by Wyoming68
No, I don't have the hose your talking about. It has had the manifold changed to a Holly Dominator.
It does have a breather cap on the fill neck that has a hose nipple with a pcv valve in a hose between there and the full port vacuum on the carb.
I don't know what the original air cleaner looks like. Mine is just a chrome dish like yours.
It does have a breather cap on the fill neck that has a hose nipple with a pcv valve in a hose between there and the full port vacuum on the carb.
I don't know what the original air cleaner looks like. Mine is just a chrome dish like yours.
The fitting i was talking about actually is mounted on the block, but as i guessed its not there
here is a pich of the original air cleaner base
as you can see i replaced my valve covers with the 69 style, but the PVC set up is the same
either way, seems like you only have half of the set up you need original or not. see pauls pics, where he is drawing gasses from both the fromnt and rear of the engine into the carb.....
you are missing the fitting that would pull gasses from the rear, possible mix match set up attempt
I am curious about another thing, what is the date code on your trim tag?
tim
Last edited by sweethence; Aug 9, 2006 at 01:45 PM.
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
Something is not coming together here. You have an open breather cap (that oozes fumes) on the oil fill tube with a hose and PCV connected to the carb? That open cap defeats the purpose of the PCV. Where is the crankcase vented?
Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by paul67
Something is not coming together here. You have an open breather cap (that oozes fumes) on the oil fill tube with a hose and PCV connected to the carb? That open cap defeats the purpose of the PCV. Where is the crankcase vented?
My thoughs exactly paul, I think someone tried a mix and match solution....looks like bubba has been up to his dirty deeds once again, shouldnt be too hard to correct though
Last edited by sweethence; Aug 9, 2006 at 01:57 PM.
Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
wyoming 68's engine bay
ok lets see.......
first let me say that is a nice clean looking engine bay...
second let me say that you PCV system is a hose shy of being right.
also I am 99% sure those are not the vette valve covers for the 68 .... but hey i could be wrong, its happened before.
If it were me i would ditch the cap hose combo and either
1 get the right valve covers with holes for PVC and hoses and air cleaner base and set it up
2. pull the valve covers you have and drill the right size hole, and get the gromets and hoses and a air cleaner base with PVC provision ing and set it up rigth.
but thats just me
you at a minimum should replace the fill tube with one similar to paul's set up, but you will still be running only a partial system.
anyone else have some thoughts
Tim
Last edited by sweethence; Aug 9, 2006 at 03:59 PM.
Thread Starter
Heel & Toe
Joined: Jan 2006
Posts: 15
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From: Wyoming
Ok...Thanks guys. That sux cuz I love those valve covers.
Thanks for the complement on the engine bay, but if I don't change something soon, she's not gonna look like that much longer. It mists oil all over it.
I think I'm going to drill the holes and do the set-up Tim suggests. Especially if that is factory correct. As for whether or not its all correct???? dunno, but the block's numbers match. Since I bought it this way and didn't do the rebuild...who knows???
Thanks for the complement on the engine bay, but if I don't change something soon, she's not gonna look like that much longer. It mists oil all over it.
I think I'm going to drill the holes and do the set-up Tim suggests. Especially if that is factory correct. As for whether or not its all correct???? dunno, but the block's numbers match. Since I bought it this way and didn't do the rebuild...who knows???
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
Those are early C2 valve covers. Get some stamped steel versions for 1968 and you will be fine. They are not expensive and will put you and the car out of its current misery. Aside from that, the engine bay sure looks nice!
Melting Slicks
Joined: May 2003
Posts: 2,387
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From: Meriden CT
Originally Posted by sweethence
OK how about the hose from the back of the block then, if you don't have it which i suspect you don't with the original motor, that i would say some one modified your engine with GM parts for personal taste or necessity, or who knows,
you need to either do what Paul says and get that 67 oil fill tube ( the camaro catalogs from the same year will also supply them), or get the vale covers with the PVC holes, the grommets, and the hoses to connect.
is your air cleaner original?
is it is, it will have the fitting to connect the PVC hose from the pass side valve cover
tim
you need to either do what Paul says and get that 67 oil fill tube ( the camaro catalogs from the same year will also supply them), or get the vale covers with the PVC holes, the grommets, and the hoses to connect.
is your air cleaner original?
is it is, it will have the fitting to connect the PVC hose from the pass side valve cover
tim
PCV my friend.... Positive Crankcase Ventilation
PVC is pipe
Here is my PCV setup... these are Billet Specialties valve covers... with their Billet PCV valve.. you can see the hose going to the large vac port on the back of the carb. The other side has the filler hole with a vent for a cap, AND a baffle on the underside.
*my plug wires have since been nicely organized.... sooo, I dont want to hear it.