Valve cover breathers????

Carmine

Well Known Member
Supporting Member 7
#1
Hi everyone, I just joined and would like to ask a question. I have a '61 348 that I bored and stroked to 434 cubes. I'm running the Edelbrock aluminum heads and the single carb. aluminum intake. The down draft tube has been eliminated and the only breathing the crankcase does is through the oil filler tube with a push on oil breather cap thats located on the intake. I read something from Edelbrock that states this is perfectly fine but I'm not so sure. Recently, I was at a car show and a guy had alot of 348-409 stuff for sale. I saw some plain valve covers and then some he said were for a 409 and these had oil breathers incorporated into them. For some reason they didn't look factory to me. The workmanship didn't look good. Seeing these got me thinking about my set up. I don't mean to question Edelbrock or their engineering, but I'm really wondering about the crankcase venting/breathing of my motor. Would any of you have any experience/ideas re. this?? Thank you very much, Carmine.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#3
Welcome Carmine,Yes you are correct,Chevrolet never put breathers in the factory valve covers. Skip's idea is a good,simple fix,as you should provide a way other than the fill tube to get the blow-by to get out of the engine.Perhaps a PCV valve in the breather added to the valve cover.
 

Carmine

Well Known Member
Supporting Member 7
#4
I put a breather in my Edelbrock valve covers. Drilled a 1.25 hole for the standard sized grommets.
Thanx for your response. Did you just use a breather in the valve cover or did you also run a line with PCV to the carb. I have an Edelbrock carb. and was thinking about runing a line from the port in the breather to the center port on the front of the carb. This is the way I saw it done at a car show recently but it was on a sbc; believe about a '63.
 

Carmine

Well Known Member
Supporting Member 7
#5
Hi everyone, I just joined and would like to ask a question. I have a '61 348 that I bored and stroked to 434 cubes. I'm running the Edelbrock aluminum heads and the single carb. aluminum intake. The down draft tube has been eliminated and the only breathing the crankcase does is through the oil filler tube with a push on oil breather cap thats located on the intake. I read something from Edelbrock that states this is perfectly fine but I'm not so sure. Recently, I was at a car show and a guy had alot of 348-409 stuff for sale. I saw some plain valve covers and then some he said were for a 409 and these had oil breathers incorporated into them. For some reason they didn't look factory to me. The workmanship didn't look good. Seeing these got me thinking about my set up. I don't mean to question Edelbrock or their engineering, but I'm really wondering about the crankcase venting/breathing of my motor. Would any of you have any experience/ideas re. this?? Thank you very much, Carmine.
Just a little update. I called Edelbrock today and inquired about the intake not having an application for the road draft tube and how would you vent this motor. He asked when I bought this intake and I told him about 2 yrs. ago but only recently got around to installing it. He said, since then, this intake has been "revised" twice. It now comes tapped with the proper fittings/hose to attach it to the air cleaner. Since I can' do this, I asked what else is available to let this engine breathe. As mentioned in this forum, he said some drill and attach a breather to one of the valve covers, then to a PCV and onto the carb. for vacuum. He also mentioned that Mr. Gasket and Spectre, make a vented oil filler cap with a nipple and also an oil filler tube with a nipple. Both could be hooked to a PCV and then to the carb. I think I might give this a try instead of the valve cover route. I've always liked Edelbrock products and have purchased alot over the years. I'm a little disappointed that they didn't engineer their first version of this intake properly. They really should have thought about what to do with the internal gasses if they eliminate the road draft tube. Just my opinion.
 

raymar58409

Well Known Member
Supporting Member 2
#6
Mine seemed to spit a lot of oil out that filler tube on the dyno above 3000 rpm. Wasn't much back pressure, more like coming off timing chain. I have a corvette filler with a pcv nipple and plan to run breathers on the valve covers if it occurs during normal driving.

Ray
 

models916

Well Known Member
Supporting Member 7
#7
Early blocks have the front breather isolated from the lifter galley. If you remove the road draft tube you need to vent the upper part of the engine somewhere other than the front vent. Not sure if they opened the passage between the pan/timing cover to the lifter galley on later models.
 

raymar58409

Well Known Member
Supporting Member 2
#8
I forgot to mention I have an edelbrock intake also. Started modifying the pan for the valley and gave up and left it out, probably part of my problem.:doh.

Ray
 

oldskydog

Well Known Member
Supporting Member 9
#9
Early blocks have the front breather isolated from the lifter galley. If you remove the road draft tube you need to vent the upper part of the engine somewhere other than the front vent. Not sure if they opened the passage between the pan/timing cover to the lifter galley on later models.
422 blocks were open from the timing cover to the lifter galley. Not sure exactly when this change happened. May be some late 814's also. 422block.jpg
 

Carmine

Well Known Member
Supporting Member 7
#10
Early blocks have the front breather isolated from the lifter galley. If you remove the road draft tube you need to vent the upper part of the engine somewhere other than the front vent. Not sure if they opened the passage between the pan/timing cover to the lifter galley on later models.
So that I don't misunderstand you, are you saying that if the road draft tube no longer exist, one or both of the valve covers should be vented because the one vent from either the oil filler tube or the oil filler cap is not enough??? Thanx for your patience, Carmine.
 

62impala409

 
Supporting Member 1
#11
The road draft tube was only used from '58-'62 on the W motors. The various GM intake manifolds had a big horizontal hole in the back where the tube was fastened into. The '63-'65 W motor GM intakes had a rubber plug installed in that big hole along with a small tube and hose connected to a pcv valve in the back of the carb. The newer Edelbrock manifolds don't have the same provision for a pcv valve connection so we have to be innovative. Some of us have drilled the manifold for a grommet and valve that connected to the carb with a rubber hose. This requires a baffle on the underside of the manifold to prevent oil spray from being sucked out of the lifter valley. This is the way I did my 2x4 setup and it works fine. Good Luck. Leo
 

Skip FIx

Well Known Member
#12
Edelbrock had two sets of baffles for the rear hole. First came with a small one that acted as a baffle and they said to put a PCV there. Alot of folks that did sucked oil. Current baffle kit(and they will send you this one is larger-like the back 1/4 of the factory baffle) and to use it to the air cleaner as a source of clean air for the motor. mine I just plugged. I used a Show Cars factgory style baffle but it does not completely cover the hole View attachment 19452

There is ALOT of oil mist in the valley area. Pontiac have a spearate valley cover that has baffling for them. The aftermarket valley pans have little baffling and suck air. Teh valve covers have alot les going on throwing oil around to sick.

My plan is to use one for a PCV as that does help suck some of the bad corrosive View attachment 19451 vapors out
 

Attachments

Carmine

Well Known Member
Supporting Member 7
#13
Edelbrock had two sets of baffles for the rear hole. First came with a small one that acted as a baffle and they said to put a PCV there. Alot of folks that did sucked oil. Current baffle kit(and they will send you this one is larger-like the back 1/4 of the factory baffle) and to use it to the air cleaner as a source of clean air for the motor. mine I just plugged. I used a Show Cars factgory style baffle but it does not completely cover the hole View attachment 19452

There is ALOT of oil mist in the valley area. Pontiac have a spearate valley cover that has baffling for them. The aftermarket valley pans have little baffling and suck air. Teh valve covers have alot les going on throwing oil around to sick.

My plan is to use one for a PCV as that does help suck some of the bad corrosive View attachment 19451 vapors out
I tried viewing the attachment but it said there was an error. Could you try again please. Thank you.
 

models916

Well Known Member
Supporting Member 7
#14
Early blocks without the road draft really need to breath. If you only have the front tube, it makes quite a mess. I used a breather in each valve cover near the front.
 

Skip FIx

Well Known Member
#15
The attachments are the same pictures as below smaller had some issues linking them.
The baffle picture is the Show Cars stock one mounted on a Edelbrock intake.

I can take some pictures of the various ones from Edelbrock this weekend.
 

raymar58409

Well Known Member
Supporting Member 2
#16
Guess I better figure out how I'm going to do mine before I put the front end on as I don't want to lean over fenders to do it. I also don't want to to anything to the stock covers. So now I need to figure out what covers to buy.
Ray
 

Carmine

Well Known Member
Supporting Member 7
#18
Early blocks without the road draft really need to breath. If you only have the front tube, it makes quite a mess. I used a breather in each valve cover near the front.
Just wondering, did you hook the breathers to a pcv valve and then to a port on the carb. for vacuum??? Thanx, Carmine.
 

Skip FIx

Well Known Member
#19
Yes my plan is to use a baffled grommet for the valve cover then a PCV then hook it to a main fitting in the carb or a spacer under the carb. Pontiacs actually had a fitting that opened into both the upper and lower plenum of the intake for theirs.
With a PCV the motor needs a source for air. The front breather tube or a "clean" source like air in the air cleaner. Many aftermarker cleaners come with a fitting for that. The newer Edelbrock kit does also.

For me I really liked the black Edelbrock valve covers on the aluminum heads for contrast. Although between them and the Edlebrock heads the valve cover gaskets don't fit great.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#20
Carmine There rubber gromets that have perferations on the bottom.Some times thier at places like Advance Auto.You can also opt for the push in breather that has a built in pcv. In my opinion,I'd mount the pcv toward the rear,on the right [passenger] side in the hopes of better getting all this bad stuff out of my motor.
 
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