Oil breather location

[Aarons Air]

I have a 68 383 motor i just bought. It has after market aluminum valve covers. With one hole in the top of each one. The drivers side hole is located close to the rear. The passenger side hole is close to the front. Are these locations correct. For a 68 383? Is there a " normal " location ? Should i use an oil breather in one or both holes ?

 

[Ranger16]

You can use either. Mine is just the opposite. I have a breather cap on the drivers side (front) and the PCV valve on the passengers side (rear). The breather cap is the intake and the PCV would be the exhaust side, being drawn into the carb.
Two breathers will not ventilate the crankcase. One side pulls fresh air in and the other draws it out.

Here is the air flow diagram. The only difference is mine (and probably yours) will be an open oil filler cap as opposed to drawing air from the air cleaner (closed system pictured below).

 

[vintage chromoly]

Ranger described the theory of a PCV system.
That said, 2 breathers will most definitely relieve crankcase pressure.

If you want to run a PCV valve, use a breather on one cover and the PCV valve on the other.
If you don't want to run a PCV valve, run a breather in each cover.

 

[Ranger16]

Yeah, I was thinking about it and just came back to correct that statement. Two breather caps will "vent" the crankcase, but won't provide positive flow through. Thanks for the clarification Vintage Chromoly.

Personally, I'd opt for the PCV system since you have everything right there, including the two holes.

 

[Yatzee]

Yeah, I was thinking about it and just came back to correct that statement. Two breather caps will "vent" the crankcase, but won't provide positive flow threw. Thanks for the clarification Vintage Chromoly.

Personally, I'd opt for the PCV system since you have everything right there, including the two holes.

You had better rethink everything written above. Has anyone wondered why there are 4 places on the covers for apparatus? I'll leave it up to you guys.

 

[oldbee]

Yahtzee sorry ur wrong. 2 holes in each cover so they can be mounted on either side of engine. Stock big blocks didn't swap sides; the rt. cover had #8 plug wire clips to route that wire next to intake mani. side.

 

[Aarons Air]

So from what i"m reading, if i ran a pcv and breather, could i put either in either side ?

 

[vintage chromoly]

Yes. One in one cover and the other in the opposite cover.

 

[Aarons Air]

Ok. Thanks everyone for the help.

 

[Cornpatch MO]

IIRC you are using custom valve covers with no spark plug wire looms attached to them . Swap sides and then your drivers side oil fill and fresh air will be towards the front , and your pcv will be on the passenger side towards the back as Ma Mopar intended..........................MO

 

[Aarons Air]

Oh. Duh. Thanks. I didn't realise they had been put on backwards.

 

[Ranger16]

So from what i"m reading, if i ran a pcv and breather, could i put either in either side ?

Correct

 

[Cornpatch MO]

Correct

Just a thought..are the holes in the valve cover ,for the grommet, the same size on each side? The grommet is probably different size inside diameter between the oil filler-breather and the pcv valve............................MO

 

[Ranger16]

Can't speak for your valve covers, but mine are the same size and interchangeable.
My guess is yours will be the same.

 

[Aarons Air]

Yes, mine are the same diameter on both sides. If memory serves, when i had a cuda, it was the rubber inserts that are different diameter.

 

[Ranger16]

If they are the same size, then the rubber insert should fit either side should you want to swap sides.

 

[coloradodave]

And, be sure there is a baffle under the PCV valve so that it doesn't ingest oil instead of vapors...VERY important.

 

[Aarons Air]

IIRC you are using custom valve covers with no spark plug wire looms attached to them . Swap sides and then your drivers side oil fill and fresh air will be towards the front , and your pcv will be on the passenger side towards the back as Ma Mopar intended..........................MO[/QU

 

[Aarons Air]

Just discovered these aren't made to swap sides. Anyone want to buy 'em ? Lol.

 

[oldbee]

WTH- can't swap sides? It's just a bigblock! It just keeps getting crazier all the time.