5.0 EFI PCV System solution.

[nvrstuk]

The barbed bulkhead fittings that are posted looked like they would be too long and extend into the valve cover too far, and you would not have room for
roller rockers and oil baffle.
This is why I was thinking, I probably go with tig welding them in place.

 

[ba123]

I cut the downward facing fitting on mine.

 

[ntsqd]

Just say no to hose clamps.

 

[nvrstuk]

Sorry I wasn't real clear. If I could find one in 3/4" or 7/8" I was wondering if the nut would be thin enough to not hit my existing baffles- (which I'm pleased with how well they work when spinning at 5500rpm for a couple min at a time) but I can always send them back if bought from Amazon or similar. Be different if it was McMaster or similar as shipping & any restocking fees wouldn't be worth it.

I like what you're working with- just trying to figure out my setup at the same time.

Might get to it by Nov... lol

 

[ba123]

That Barb I just posted has up to a 3/4 and it at least looks somewhat thin but I bet you could find thinner.

I used this one on my Fuel Fill Hose...didn't work as perfectly as I'd hoped but rather low profile nut:
https://www.amazon.com/dp/B09KZTCCWB/?tag=classicbroncos-20

Could prob find a bulkhead fuel vent fitting or use something like this:
https://www.summitracing.com/parts/...b2PzeHay8diqM03zKgYLCSSncF8I9ROxoCfFsQAvD_BwE

Fuel Cell Bulkhead is what I was trying to remember:
https://www.summitracing.com/parts/sum-220282b

 

[nvrstuk]

Good finds in there! Thanks for all the links!

 

[ntsqd]

FWIW AN fittings use SAE fine threads, so you can use a jam nut of the right size on any AN bulkhead fitting to create what it looks like you're trying to do. Couple that with some Dowty seals, Stat-O-Seals, or the correct size o-ring and I'd think you're there.

 

[ba123]

Traced my oil leak to my rear main that’s been pushed out slightly…maybe I’ll upgrade my hose size NOW!

 

[Broncobowsher]

-8AN breather hose on a whopping 170 c.i. engine, I considered -6 to be too small for the fresh air. The PCV side got 3/8" tubing and hose.

When I built a 331 I tried a 3/8 breather and PCV. On a fresh engine that didn't have the rings seated in I would build too much crankcase pressure on a hard pull. I ended up changing to a 5/8 fresh air, because those there the parts I had on hand. I'm planning on a 289 boat engine and am thinking of 5/8 fresh air breather on that one as well. Mainly because I know I will have the throttle pinned wide open for 15 minutes at a time.

 

[ntsqd]

To be honest at the time I felt like -8 was a bit larger than necessary, but I had all of the pieces as they were cast-off's from a former employer and the next step down, -6, just felt too small.

Seems like, and I have a hard time wrapping my head around why, but it seems like the vacuum side works fine with smaller plumbing. It's only the fresh air side that needs to be big.

If that 289 is going to be wound up tight I wouldn't hesitate to step up to 3/4"

 

[ba123]

For our uses, I’d bet 3/8” is more than plenty. That’s what the factory put on there and that’s what my throttle body has so it’s restricted at that point anyway.

 

[ntsqd]

Maybe. Didn't you say that a rear main seal had pushed out?
I can say that the 5.8 in my '96 has a 1/2" breather hose and only spins up to 4k if I work at it pretty hard.

 

[ba123]

Well, honestly, that leak isn't as straightforward as I feel it should be. Now I'm thinking it was the pan over the main and just needed to be a little tighter. Such a PIA spot!

The seal was pushed out a tiny bit, but I also had a 5/16" feed in there which looks much smaller than a 5/16" opening.

So I'm putting a 6an bulkhead with a 6an swivel 90° and then 3/8" hose all the way and it should create a ton more flow.

 

[Broncobowsher]

I tried to copy OEM design. Which I heard was marginal undersized. That is when I used 3/8 everywhere.
It was a fresh build. Backyard style. Rings usually take several thousand miles to seat in when I build engines like this. So guessing the ring seal wasn't the greatest. Factory stuff has a lot more quality control and seals a lot better on first start. And probably why factory got away with 3/8 for the fresh air and why it didn't work for my build.

 

[jamesroney]

For our uses, I’d bet 3/8” is more than plenty. That’s what the factory put on there and that’s what my throttle body has so it’s restricted at that point anyway.

You do realize that the AMC inline 6 on the Wrangler 4.0 uses a constant orifice to meter the vacuum to the crankcase. The "PCV" valve is a solid plastic fitting with a 2.6mm hole in it. (0.100") A 3/8 hole has about 14 times more area.

The non-PCV Ford 260 came with a 1 inch road draft tube. And the 428PI in the GT500 came with a 5/8 diameter tube ported to the non-vacuum side of the throttle plate between the air filter element and the carburetor. (and yeah, it "worked" about as well as you would expect.)

For Every Ford engine built from 1986 to 2002...a 3/8 ID inlet was MORE than adequate. Furthermore...blow-by would serve to provide MORE crankcase air volume...thus making the need for the inlet size LESS. In fact, if you had enough blow by...you wouldn't need an inlet port at all. (don't try this at home.)

It is worth noting that under some conditions, inadequate scavenging can allow oil to accumulate in the upper plenum. This is why the PCV vacuum routing on the 5.0HO is ported to multiple locations on the plenum. You need constant air flow to prevent pooling.

 

[ntsqd]

The cross-sectional opening of a 3/8" hose may be large compared to the opening of a single point restriction, but how does 6" to 36" of that hose flow in comparison to the single point restriction? The "Garden Hose" problem, make the length long enough and it will restrict the flow even though it's cross-section open area seems like it should be more than large enough. I honestly don't know where the balance point is, I barely recall the math needed to figure that out. I'd rather just make it bigger and move on to the next list item.

 

[ba123]

i think this dumb 5/16” barb is smaller than it should be.

Anyway, here’s a comparison between the 5/16” I was using and the 6an I’m am changing to:

Pretty significant, imo. The silicone 5/16” hose I was using was pretty large but still changing that as well.