Hot Rod Forum banner
1 - 20 of 55 Posts

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #1 ·
I have a set of old school Edlebrock Valve Covers with Breathers on my 327 c.i. Chevrolet. The intake manifold has the oil fill tube and breather on the front.

Is it necessary to have the valve covers with the breathers on this engine seeing that it already has a breather on the intake manifold?

Can I just remove the plastic filters which are totally disintegrated and put an old sock in them and plug up the filter?

The engine has a slight amount of blowby and it comes out the breather on the passenger side. I want to plug it up but keep the breather look.....Is it OK to plug up these breathers so they are not functional on this old 327 c.i.?

I know I can tear it down and rebuild it to eliminate the small blowby smoke.......but I don't want to at this time.

All suggestions and input greatly appreciated.

Thank you~~~~~~~~~~:
confused:
 

·
Registered
Joined
·
1,684 Posts
Do the Edelbrock valve cover breathers come apart so you can replace the filter inside? Does the drivers side valve cover have a PCV installed. If so I would leave the breather cap on the passenger side.
 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #3 ·
Yes they come apart. I took out the old foam mesh filters that were deteoriating. Is it necessary to have either one functional when I have the original intake with the Oil Fill Tube and Breather cap on the tube?

This is a 1967....327 c.u.i. with no PCV as this old engine did not come with a PCV Valve.

Thanks~~~~~~~~Ron
:confused:
 

·
elkyholic
Joined
·
327 Posts
If the engine is old its nice to have as much breathing as possible
I agree. The oil coming out of the breather is evidence you are getting blow by because of the wear on your rings/cylinders. If you block it off, you might cause gaskets to leak. :sweat:

I would look for something to replace the mesh filter. A replacement breather (or filter element) might slow down the amount of oil out of the breather.
 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #6 ·
If your filler cap is the slide over cap and breathes well enough?If the engine is old its nice to have as much breathing as possible
Yes the filler cap slides over and has the built in breather capacity. It works fine....but somebody added the old Edelbrock Valve Covers with the breathers on the covers. I'm just going to stuff something in them where the old deteoriated filters were and put the tops back on the breathers.

I like the look of the valve covers with the breathers but don't like the little bit of blowby fumes coming into the passenger compartment. I can see from other posts and looking at original 327 c.i. engines on ebay Camaros that it will work fine with the new slip on breather cap on the oil fill tube just like they came from the factory. They didn't use breathers on the valve covers back in 1967.
::cool:
 

·
TAKE A KID TO A CAR SHOW
Joined
·
2,865 Posts
Vinnies right and it will help get rid of moisture, gas, acid, and other contaminants extending engine life And a pcv adds a few HP! Even if you hook it to plenum vacuum!
Do your valve covers have baffles under the breathers?

Jester
 

·
Hot Rods are Built, not Bought
Joined
·
829 Posts
I had the same set-up you are describing on my Model A when I first built it. 1972 era 355 sbc (no road draft tube), intake mounted oil filler with breather, no breathers in the valve covers (corvette aluminum finned covers). I ended up using a cotton filter on the breather due to blow by, to keep oil drops from splattering on the body.

Worked great until after about 300 miles, the first time I ran the rpm's up to about 6,000. It blew the seals out of the fuel pump and puked oil all over the header. I thought for sure I blew up the engine, based on all the smoke I saw in the rear view mirror.

I rebuilt the fuel pump (Holley) and then installed a moon breather in the driver's side valve cover. I then installed a '67 Corvette oil filler tube (with a pvc valve port) in the manifold, installed a pcv valve, and used a cap instead of a breather on the filler tube.

I haven't had any issues since, no more drippy oil blow by issues, no more blown fuel pump gaskets.... it's been troubble free for the last 9 years.

Hope my experience is helpfull to ya!

 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #10 ·
I'm not getting any oil blowby....just fumes (light smoke). The engine stays clean. Just want to get rid of the fumes. I'm going to plug up the valve cover breathers and just use the factory breather on the oil fill tube at the front of the manifold and see how it works out for me.

Thanks for all your suggestions.
:thumbup:
 

·
Registered
Joined
·
4,203 Posts
I had the same set-up you are describing on my Model A when I first built it. 1972 era 355 sbc (no road draft tube), intake mounted oil filler with breather, no breathers in the valve covers (corvette aluminum finned covers). I ended up using a cotton filter on the breather due to blow by, to keep oil drops from splattering on the body.

Worked great until after about 300 miles, the first time I ran the rpm's up to about 6,000. It blew the seals out of the fuel pump and puked oil all over the header. I thought for sure I blew up the engine, based on all the smoke I saw in the rear view mirror.

I rebuilt the fuel pump (Holley) and then installed a moon breather in the driver's side valve cover. I then installed a '67 Corvette oil filler tube (with a pvc valve port) in the manifold, installed a pcv valve, and used a cap instead of a breather on the filler tube.

I haven't had any issues since, no more drippy oil blow by issues, no more blown fuel pump gaskets.... it's been troubble free for the last 9 years.

Hope my experience is helpfull to ya!

My '56 Chevrolet had Corvette valve covers and a aftermarket breather arrangement as shown in the photo. The aftermarket breathers were mounted in the sides of the valve covers so the rocker arms would not flood the breathers with oil. I had a 1965 Chevrolet FI 30-30 solid lifter camshaft and the lifters would shoot oil over the fenders when I was adjusting the valves. I finally stopped the excessive rocker arm oiling by using 1965 Chevrolet edge-orifice solid lifters that restricted oil flow to the rocker arms. The GM edge-orifice lifters also saved my rod bearings!

The 1962-1866 Pontiac engines had problems with oil blowing out the valve cover breathers. The Pontiac 421 HO and SD engines had baffled valve cover stacks in each valve cover that were about 4" high. That was a fruitless attempt to prevent oil from blowing out the breathers at high RPM. The passenger side breather stack was in the middle of the valve cover, between the rocker arms and it did not throw oil. The other breather was in the front of the driver's side valve cover, directly above a rocker arm. That was the breather that blew oil all over the firewall. I reduced oil blowing out of that breather stack by pushing a piece of foam rubber down the stack and eliminated oil blowing by pushing a piece of rag down the breather stack. . I have even seen Pontiac owners at the drag strip wrap their breather stacks with a rag to prevent oil blowing. .

Conclusion:
Where you put those valve cover breathers makes a difference. Do not put them over a rocker arm. The oil blowing problem was finally solved when GM went to the closed PCV system in 1968.
 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #13 ·
I've never had the valve covers off this engine. Apparently there are no baffles under the breathers because oil puddles at the base of the breather.

I just want to get rid of the fumes. I know a PCV Valve would solve the problem of fumes.....but I don't want to drill a hole in the top of these old nostalgia valve covers and fit a PCV Valve setup.


As stated earlier...I'm going to plug off the valve cover breathers and use the factory fill and breather and see if it helps.

Thanks for all your interest.
:cool:
 

Attachments

·
Registered
Joined
·
4,203 Posts
Location, location, location.....If those breathers had been installed on the opposite side of the valve covers, no oil would escape. See the previous photo of the Corvette valve covers. The side mounted oil breathers should always be installed on the intake manifold side (high side) of the valve covers.

When the engine is running, oil is tossed off the rocker arm and onto the exhaust side of the valve covers and then it puddles in the breathers. If you remove the breathers and cover the breather hole in the valve covers with a plate, the fumes and oil will not have any path to escape. Problem solved.
 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #15 ·
Location, location, location.....If those breathers had been installed on the opposite side of the valve covers, no oil would escape. See the previous photo of the Corvette valve covers. The side mounted oil breathers should always be installed on the intake manifold side (high side) of the valve covers.

When the engine is running, oil is tossed off the rocker arm and onto the exhaust side of the valve covers and then it puddles in the breathers. If you remove the breathers and cover the breather hole in the valve covers with a plate, the fumes and oil will not have any path to escape. Problem solved.
Total agreement!!!!:thumbup:
 

·
elkyholic
Joined
·
327 Posts
From the OP

"The engine has a slight amount of blowby and it comes out the breather on the passenger side. I want to plug it up but keep the breather look"

Not to pick nits, but....

The PCV is the best answer, only if you are trying to maintain the period look with the valve covers and breathers would I consider omiting the PCV. But you still need to vent the gases. Only way you are going to stop the fumes is with a PCV.

Maybe fit a PCV valve into the breather then add a hose to vent gases to the intake.
 

·
Hot Rods are Built, not Bought
Joined
·
829 Posts
I'm confused? Why not just install the 67 vette filler tube as I stated earlier, that has the pcv installed in it. You can leave the breathers as they are. Then the engine will pull fresh air into the breathers and suck that air along with any oil fumes through the pcv valve.
 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #18 · (Edited)
That would be my choice with the '67 Vette fill tube if I decide to do some changes. The next problem would be finding one of those tubes without costing an arm and a leg. I want the old nostalgia look in my '49 Merc chopped sled.:cool:
 

·
Lost In The 50's
Joined
·
139 Posts
Discussion Starter · #19 ·
That would be my choice with the '67 Vette fill tube if I decide to do some changes. The next problem would be finding one of those tubes without costing an arm and a leg. I want the old nostalgia look in my '49 Merc chopped sled.:cool:
I found Corvette Central sells reproduction Oil Fill Tube, Cap and Threaded PCV Valves for '66-67 Corvette. Should be able to do the whole changeover for less than $100.00.

How do you get the old oil tube out after many years of being in the manifold?

Do you put some type of sealer on the new tube and just tap it in with a block of wood and hammer?

Where does the hose go?

Never done it before so I have a lot of questions before attempting. Thanks in advance~~~Ron
:thumbup:
 

·
Hot Rods are Built, not Bought
Joined
·
829 Posts
If you have a Holley carb it has a dedicated PCV Port, as shown here:


To remove the old filler tube I used a slip joint wrench with a piece of inner tube rubber wrapped around the filler neck. Get the wrench as close to the manifold as possible.

Or you could use a strap wrench if you own one, I don't.

I put some Red RTV on the new filler neck before I tapped it into place. The new neck can be installed by placing a scrap piece of wood across the top of the neck and tapping it into place with a ball peen hammer. Just be sure to orient the PCV valve in the right direction before installing the tube.

:thumbup:
 

Attachments

1 - 20 of 55 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top