Hello, everyone. I am brand new to this form so forgive me if I’m posting in the wrong area. I just recently bought a 1970 Dodge Dart. It has a 360 magnum out of a 98 ram pickup. It has been converted to a carburetor and has a 600 efm Holley street warrior on it. I’m having issues with a slow oils leak that only happens while the car is running. I have had the front main seal replaced (where we originally thought it was leaking from) and it is still leaking. It also leaks around the valve covers. This is a new build and only has 500 miles on it. It was driven hard by the previous owners before the break in period was satisfied. My question is: does anyone know where I can find a vacuum diagram for a carbureted 360 magnum. Right now they have a breather cap on the passenger side valve cover and I think that is wrong. The way I understand it is that you need a PCV valve that goes from the passenger valve to either the carburetor or the intake manifold. The driver side gave cover should have the breather cap? Any help would be greatly appreciated. Thank you
Confused on PCV system for 360 magnum
- Thread starter Toddh98
- Start date
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j par
Well-hung Member
You're correct that it needs a PCV. It doesn't matter which valve cover it comes out of. Positive crankcase ventilation. You just want a sucking action coming out of the motor.
Since I have a carburetor, where does the vacuum line hook up? I don’t think it will have a spout on the intake manifold since it’s originally a fuel injected block
I recently built and swapped in a 5.9 Magnum. I also had leaks around the valve covers. I did two things that fixed the problem. 1). I ground all the valve cover bolts to make them shorter. I think they may have been bottoming out.
2). Ran a hose from the breather on the driver's side valve cover to the air filter assembly. Before that, I had a PCV to the carburetor from the passenger side, and just a breather on the driver's side. I found a breather with a nipple to run the hose to the air filter assembly. No more oil leaks.
If you zoom in you'll see the hose leaving the breather.
2). Ran a hose from the breather on the driver's side valve cover to the air filter assembly. Before that, I had a PCV to the carburetor from the passenger side, and just a breather on the driver's side. I found a breather with a nipple to run the hose to the air filter assembly. No more oil leaks.
If you zoom in you'll see the hose leaving the breather.
Base plate of the carb will have a large spout. Hook it up there.
Here is a correct PCV system.
Do you have any idea why the set the engine up without a pcv valve in the first place? Thanks everyone for the replies. This is already turning out to be an awesome community. Also, what kind of air filter did you buy that had a vacuum spout? I’m sorry if these questions are silly, I’m very much still learning
No silly questions...only silly answers 
Maybe they were in a hurry...or just didn't realize how important the PCV is.
The Edelbrock air cleaner assembly has a nipple to attach the breather hose to. I bought the small diameter one since the filter was short enough to fit under my hood. Planning to get the larger diameter one and source a 2" high filter to clear the hood. Should have done that the first time!!
Edit:. It's awesome to see a young gun getting elbow deep into our ole Mopars!!
Maybe they were in a hurry...or just didn't realize how important the PCV is.
The Edelbrock air cleaner assembly has a nipple to attach the breather hose to. I bought the small diameter one since the filter was short enough to fit under my hood. Planning to get the larger diameter one and source a 2" high filter to clear the hood. Should have done that the first time!!
Edit:. It's awesome to see a young gun getting elbow deep into our ole Mopars!!
Yeah, I love them! This is my second. I had a 71 dart for awhile. I stole this car for the price I paid for it. I’m almost ashamedNo silly questions...only silly answers
Maybe they were in a hurry...or just didn't realize how important the PCV is.
The Edelbrock air cleaner assembly has a nipple to attach the breather hose to. I bought the small diameter one since the filter was short enough to fit under my hood. Planning to get the larger diameter one and source a 2" high filter to clear the hood. Should have done that the first time!!
Edit:. It's awesome to see a young gun getting elbow deep into our ole Mopars!!
famous bob
mopar misfit
Aint no big deal to make your own tube for it -----------
Krooser
Building Chinese Free Engines since 1959...
Notice that the pcv draws vacuum from the carb fitting UNDER the throttle blades. That's important because you want full vacuum to the pcv at all times.
The closed oil filler cap is also good.
A Carter or Edelbrock carb will have the correct fitting at the front of the carb. Most street type Holley's will also have one.
The closed oil filler cap is also good.
A Carter or Edelbrock carb will have the correct fitting at the front of the carb. Most street type Holley's will also have one.
Breather cap in one valve cover and a pcv in the other valve cover hooked up to the large port at the base of the carb.
ChargedDart75
Well-Known Member
One thing you can do is get an oil fill cap that has a breather built in and put the PCV valve in the passenger side cover.
My Magnum in my Dart. PCV and breather. Just like any motor.
Be sure there is a plate or baffle under the PCV so it doesn't suck oil.
That works. Cross flow is best.
Excellent point. Baffles are a must.
j par
Well-hung Member
Is there a chance your vacuum advance is on the wrong side of your carburetor?...
My two
HArd to tell with the goofy pics that are posted nowdays. I don't know where they come from or how they are posted but we have a great built in photo app here.
pishta
I know I'm right....
If you got blowby, It must be able to vent and the air cleaner is a good place for it as it will get ingested and reburned. Usually magnum valve covers don leak as their gasket surface is machines unlike the cast LA heads. PCV doesnt do **** at idle (very little bleed) , its closed, imagine where all that crankcase pressure is going when its closed? I'd not even run a stock PCV valve with a performance cam, just a breather and a 1/2 to the bottom of the air cleaner inside the filter footprint. It will draw air in through the valve cover breather, pick up all the crankcase crap and reburn it. If you do run a PCV with a performance cam, the low vacuum developed by the cam will trick a stock PCV into opening at idle, creating a vacuum 'leak' at idle and fouling up your A/F. Try getting an adjustable one.
j par
Well-hung Member
I know on the 360 on my truck if I pull the vacuum hose off the keg intake manifold at idle there's some tremendous vacuum...
I've been testing it both ways. Full vacuum and ported vacuum. I'm running a limiting plate. Finally got my transmission kick down set perfectly. Then, the Steer and Gear rebuilt power steering gear developed a leaky pinion shaft seal. Long story, but I'm pulling it out and sending back for warranty work (fantastic customer service btw). So...I'm off the road until I get it back. As Rusty says "Back to our regularly scheduled program".
Johnny Dart
Well-Known Member
69_340_GTS
Well-Known Member
He's asking about PCV, not vacuum advance. What makes you think vacuum advance has anything to do with the PCV system?
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