A bit more on the Oil/Air Separator

[C9]

Part of the thinking about this oil/air separator is getting a little altitude into the PCV system as well as pulling the air/oil mix through a separation medium.

Altitude seems to help some competition cars that weep oil at the breathers.
Owners will mount a pair of breathers up high on the firewall and plumb them individually to the rocker covers on each side.
Many times the aftermarket cast aluminum breathers don't have adequate baffling and a little added height helps.

Height is part of the deal for the comp car guys and adding a semi-filtration medium to a closed PCV system seems to help on the street.
Said medium needing to flow air without much resistance.

The overall length of the separator body is 9".
Body length sans caps is 7 3/4"
The body is 2" OD x .120 wall aluminum tube.

The bottom cap is tapped 1/4-NPT and a right angle Earls aluminum fitting installed.

The fitting is pipe thread to 3/8" fuel line hose.
The bottom cap is epoxied to the body with JB Weld which is an excellent way to do some of this stuff.
TIG is nice, I have one, but JB is a lot quicker than dragging the TIG out and setting it up.

Upper cap has a single O-ring groove machined into it.
The upper part of the body ID has a smooth chamfer to give the O-ring an easy entrance.
A touch of engine oil is used to make things easy.

The upper cap is also machined to accept a PCV valve - SBC in this case -and the Buick grommet seen in one of the pics.

The mount bracket is machined 1/4-20 for a set screw, but an allen was used since I was out of set screws.

The separator is a little rough, especially the bracket and that's because it's in prototype form.
No use polishing things up if it turns out not to work.

Filtering medium is one full hunk - two come in a box - of stainless Brawny brand pot scrubber easily obtained at most any grocery store.
You can get copper pot scrubber if you prefer, look for Chore-Boy brand.
Both of these products look a bit like a pile of lathe cuttings/shavings and won't cut your hands.

Un-sophisticated testing - as in blowing through the hose, separator and PCV Valve with the separator body empty and doing it again with the body packed with the Brawny stainless steel stuff shows very little added resistance to air flow.

Along with having to run uphill, the oil is further impeded by the filtering medium - which is not there to filter, but to catch oil as the oil/air mix passes through and allow drainback.


This first pic shows the home-made fittings that plug into the original PCV grommet at the rear of the intake manifold
The straight fitting was used and as you can see in the 2nd pic, the line runs uphill to the fitting then turns down which isn't good because oil will collect and probably enter the intake manifold on start up.

The bottom line needs to be downhill all the way so oil will drain back from the separator at low speeds and when the engine's shut down.
The line in the pic ended up going uphill.



I ended up making another fitting, this one with a 90 degree turn built in so the line would run downhill.



The next two pics are an overall view.



As you can see, crankcase oil/air is picked up at the bottom of the separator via the hose plugged into the original PCV valve grommet at the rear of the intake manifold.

The PCV valve at the top of the separator feeds mostly oil-free air into the PCV bib at the back of the intake manifold proper.

The pics show the drainback line running uphill due to the straight fitting, but with the 90 degree fitting in place the line runs downhill all the way.

I'm fairly sure this setup would work fine with a shorter body on the separator.
32's have a fairly tall engine compartment, but the one in my roadster is getting crowded.

So far, the separator seems to be doing the job.
No smoke apparent on a half throttle run up a freeway on-ramp..
A short full throttle run through 2nd gear didn't show any smoke either, but I really need to make a hard, full throttle 1st & 2nd gear run.
Haven't had a chance to do it so far.

After doing a full throttle run the intake manifold will get pulled since the stock Buick sheet metal bathtub style intake gasket has been removed.
That done a short time back due to I blew a head gasket and no intake gaskets were available locally - for two weeks.
I ended up making a pair of intake gaskets from .030 Velumoid paper.
They work quite well.


The old bathtub style intake gasket will have the intake & water ports cut away and the bathtub installed over the valley then the new Fel-Pro Print-O-Seal intake gaskets will be installed.
While I'm in there I'm going to install a machined breather/crankcase air pickup of my own design just below the stock PCV location which is now the crankcase air pickup area for the oil/air separator.
The combination of the bathtub and internal breather should make it all work pretty well.

Nice part about running the car like it is now - sans bathtub which keeps hot oil off the underside of the intake manifold and also keeps most of the flying oil away from the original, stock location PCV valve - it makes for a good test for the oil/air separator.

Disregard the filthy engine compartment.
It's mostly dust.
I live next to a dirt road and it's tough to keep the car clean.
Not to mention too darned cold to wash it during the winter.

I drive the roadster during winter, 16 degrees F being a personal best.
Up till then, 26 degrees was the lowest temp I'd had it out in.
Thought I was doing good until a Harley rider cruised past....

[jaybee]

Nice work, and thorough as with all your work.  Is this the piece you were building from a used AC accumulator?

[Dave]

Nice.. By the way I left this am for work.. About 6:15.. Ice on the windscreen and was sliding around the hood getting to the eway. 15 miles down the road a guy comes on on a goldwing I look at the temp on the mirror.. 26deg.. My harley is in the garage..    
Dave

[C9]

Is this the piece you were building from a used AC accumulator?

Yes and no.
I thought the AC accumulator/dryer would be a good way to add capacity if needed.
A surge tank if you will.

I'm thinking now the AC thing will make a good radiator overflow tank for my 31.
Funny part is, some of these aluminum tanks look as good as a Moon tank finish-wise and some of em look like heck right off the bat.

The overflow is a way down the line project-wise, but I'll post something on it when I do it.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Nice.. By the way I left this am for work.. About 6:15.. Ice on the windscreen and was sliding around the hood getting to the eway. 15 miles down the road a guy comes on on a goldwing I look at the temp on the mirror.. 26deg.. My harley is in the garage..    
Dave

Eway?
Express way?

Them Harley guys are somethin' else sometimes.
Many years back I was outside the control room of the power station where I worked.
We were in the middle of a cold spell with temps at 11 degrees F.
About dawn I was inspecting a transformer and a Harley guy comes cruising past.

He was going pretty slow though....

[tomslik]

hey c9, i've got 1 accumulator so far...btw, every once in a while we get 'em that look a LOT like your surge tank, want me to send ya some of those too?

[C9]

hey c9, i've got 1 accumulator so far...btw, every once in a while we get 'em that look a LOT like your surge tank, want me to send ya some of those too?

Yeah, that'd be cool.

Thanks.