Technical 327 with no oil filler and breather

That is an option as I do have room. Is there any issues with the breather / filler tube to sitting low in the valley? As in, filler tube just high enough to fit a breather. Apart from it being a challenge to adding oil in.

 

You could put a smaller diameter tube behind the thermostat housing or in front of the distributor and then open it out to take an old style breather cap. It would be a bastard to fill with oil, but the air will get in. The height of the cap won't matter.

 

Thanks mate. I appreciate that.

 

And If I put the original road draft oil separator canister back on would I get away with not doing the PCV conversion? That way I’m simply adding a small tube / breather to the intake.

 

Yes, and no. You would lose the benefits of the PCV system.

I would put the oil separator back in the lifter valley, put a core plug in the hole where the road draft tube was, with a grommet and PCV valve in that. Run a hose from that, to manifold vacuum.

For the air inlet, I would put a round mushroom filtered breather between the forward runners of the intake manifold, in a grommet.

It will be fine there. It is, after all, Positive Crankcase Ventilation. It is not so critical that the valve covers be involved.

 

To clarify why you need the oil separation canister. On the early Chevy V8 engines there was a road draft tube that was connected to the hole in the rear of the block. The canister was included to capture the oil in the lifter valley. If you add a pcv to the rear hole and connect to the base of the carburetor the canister is necessary to limit excessive oil from contaminating the pcv. The reason for the breather on the oil fill is to vent the engine and is necessary for the pcv to function correctly. So if you add a fill tube with a breather cap the system function as designed. No need to drill the valve covers or add breathers to them.

gimpyshotrods beat me to the conclusion that will function correctly

 

Sometimes I get over the line first, but not often!

 

Jughead ,
That intake could be drilled and tapped for a oil fill hole .
You could go on the base,,between the thermostat riser,,,,,,and the front intake runners .
Since the intake has an air gap base,,,,,,that area has a very thick section of aluminum .
You could drill and tap for a 1/2 inch pipe thread,,,,that hole is very close to 3/4 inch o.d.
You could install a flat Allen plug in there,,,,,and it would almost be invisible.
Since it is pipe threads,,,it will self seal against leaking .
You could always use a small diameter funnel to fill the oil level .

Im still thinking about your pcv deal,,,,,I don’t have any ideas yet on that .

Tommy

 

A good idea. I’m more likely to do this in front of the distributor and include a breather on it. This will be relatively hidden. I’m still reading through comments and suggestions on whether I do a PCV conversion or put the original road draft oil separator and canister back on.

Previously the engine was running (for years) with only the original road draft oil separator / canister and a NON VENTED oil filler on the front front of the intake with no issues.

 

Your most likely running headers for race use so check out a header crankcase evacuation system like #ALL34145, drill and tap your intake for water pump 5/8 hose nipples, you don't have to molest those valve covers.
Install the supplied breathers or a oil seperator canister between the intake and the header.
Got some pictures of how I drilled and tapped my tunnel ram intake along with making a baffle to keep oil from being sucked into the headers at high rpm.
I also had success using a Moroso lifter valley baffle #25050 if you don't want to make your own.

 

One thing not mentioned when venting is removing condensation from the internal air of the motor. If you live in a humid climate this is more important. Virtually all US V8s built after the late '60s have the fresh air intake on one valve cover and the PCV on the other precisely for this reason. The motor is basically a four-room 'house'; the crankcase, lifter valley, and each head are each 'rooms'. The crankcase with all the whirling parts has plenty of air circulation, and as it vents into the valley, the valley has a fair amount. But the heads become a 'dead air' space if all venting is done at the intake. With a modern PCV system, you have cross-flow venting of all areas. As anyone can attest who has pulled a valve cover off a high-mileage '50s V8, scraping large amounts of 'stuff' off the inside of one was pretty common, something you never see on the newer ones. Condensation promotes sludge, and sludge can end up anywhere. Condensation also holds contaminates in suspension and will release them back into the motor.

 

I got the feeling the OP thinks he knows better than the engine manufacturers and engineers. Sometimes people need to learn lessons the hard way. You can lead a man to water but you can’t make him drink.

 

Many thanks!

 

Why?

 

You need to loosen the nut on the pump arm. The accelerator pump won't work with it that tight.

 

I have the Glass 32’ 5 Window thread! I did some of the same things. Found some old 62 corvette valve covers and my wife bought me a 350 crate motor, plus I had a bargain aluminum intake. No breathers any where! I drilled the intake for the oil filler neck by hand. Drilled carefully just behind the Holley, tapped, and installed a screw in pcv valve and a Moroso baffle under the intake, just make sure you drill in a single layer of the intake, not in an intake runner and for good measure I installed a Moroso lifter valley baffle, couldn’t hurt, right? Carb breather is in the back of the Holley 600 DP. Check out my thread for pics, pages 20 to 23.

 

I don't want to highjack the thread or muddy the waters, but I have a question that I've been wondering about that fits into this conversation.

I have a 2 bolt (casting number 3932386), medium journal (350 3932442) crank, .030 over 327 SBC (according to the numbers on the pistons), and a set of '291 heads. My intentions are a C-26 Edelbrock dual quad intake, decent sounding cam, Corvette finned valve covers and an oil fill tube with a vented cap. I'm not totally against running breathers in the VCs, but would rather not, if given a choice. It very well could see the result of my right foot being heavy are times, but no drag strip time. If all that being said, what is the best way to vent it, keeping it looking older and traditional?

 

Except it wasn't fine, you just didn't operate it long enough to realize that it was causing issues.

One thing that I forgot to mention, and that I don't think that anybody else mentioned, is the effect of not just the moisture, but blow by plus moisture.

No matter how new the engine is, and how little it has been operated, it has some blow by, that amount will increase over time.

Combustion byproducts making it past the piston rings and into the crankcase, when combined with the moisture that has condensed, and hasn't been removed by the PCV system, will form rather aggressive acids.

These acids will deteriorate your oil, and before you have a chance to change it they will cause corrosion inside your engine, and start stripping the top layer off of your bearings.

A whole lot of folks like to believe that the PCV system was invented just for smog, it was not. It was also developed to eliminate this exact problem. It was beginning to become very difficult for manufacturers to give warranties on vehicles that had a time bomb built into them.

 

Well stated Gimpy, and absolutely correct!

 

As long as there's no PCV valve in the way, then this will work. It will let the engine collect condensation and acids and such that would be prevented by having an open breather on the oil fill tube. But if you plug up that rear opening with a PCV valve, you'll also let the crankcase build pressure when the blowby exceeds what the PCV valve will let out.

 

"The accelerator pump won't work with it that tight" ??

 

Right , it takes all the travel out of the arm. That is probably the number one mistake you see with a Holley.

 

I have no binding whatsoever. What part hitting what are you talking about??

 

You won't have any binding, you eliminate or greatly decrease the pump shot causing the car to stumble. The part I am talking about is the nut at the left front of the carb with the spring compressed. That needs to be loosened up.

 

I've been reading/studying this thread for education looking towards the future.

I currently run a 350 with breather in one VC and PCV in the other.

I have several sets of pristine valve covers that don't have any holes in them, chief among them are Corvette.

I have been thinking of changing the intake manifold to one with oil fill/breather (at the front) and putting a PCV somewhere in the back of the intake or block. Based on what I'm reading here it sounds like it might be a bad idea to replace the "cross flow" ventilation with "front to back" ventilation. What happened to the older engines that had breather at the front and a road draft tube? Front and back like I'm envisioning?

Should I shelve this idea and stick with what I have?

 

Friend of mine in the 70's PCV vented his SBC by utilizing a finned, cast aluminum fuel pump block off plate that he milled a flat spot/threaded for a threaded hose nipple that he hosed up to the PCV/under the air cleaner. Never had any issues.

IMHO, adding valve cover vents usually looks like a quick & dirty pit hack job, especially on nice finned covers.

 

The engine don’t care which way the air flows as long as it flows. Left to right, right to left, front to back, back to front as long as it flows.

 

You do need a vented oil fill also. Otherwise you will just end up with dead air I would think. Kind of a in with the good air out with the bad type of thing.

 

I thought these Moon valve cover breathers looked OK; at least a bit better than the the quick & dirty hack job someone had done drilling holes for a PCV and push in breather right in the middle of the Edelbrock script. Little welding and some router "milling" brought them back to life. Anyway; the breathers let fresh air in and the Corvette style PCV in the sealed fill tube pulled it out.

 

looks great!