TECH: PCV for your SBC (or any other engine for that matter)

If you have an older block with provision for a road draft tube, why not just do what I did. I put in a PCV for under $10 bucks. Cheap tech!

http://www.jalopyjournal.com/forum/showthread.php?t=151629

 

Looks like theres about 67345586873564 different ways to do this, I need to pick one and get it installed.

 

Hey, Don't mean to hijack this thread, but I've seen a couple posts lately on the PCV issue and smallblocks that got me wonderin' I got a 66-67 283 with and Edelbrock intake and 4 BBL carb and breathers on both valve covers. Do I need to run a PCV valve on this setup?

 

I did a similar setup on an Edelbrock Performer.....but I shortened a fill tube and mounted it at the rear near dizzy and threaded the pcv up front....gave me more options of upper radiator hoses.......
I found the pipe threaded PCV on the Fram parts rack at Shucks.......

 

The question of how Burgers set up on the pcv deal could be working without consuming oil has been rattling around in the huge expanse of space(the boxcar)lol that houses my pea sized brain and then a while ago it hit me like a bolt out of the blue.

(side note)
I have known of at least 2 people in the past who stuck their pcv valve in the intake and they sucked "literally" tons of oil out of the lifter valley until they were baffled.1 guy consumed 2.5 quarts in an 85 mile drive and thought his new motor was screwed up.The other guys rig just smoked alot and freaked him out till we came up with a solution.
Which led me to ask if Burger was actually using the set up or had just had put it together and not used it yet.His reply is above.

Anyhow I have begun to theorize that the reason the Burger set up works is because the rise and 90* turn of the street elbow is acting like a separator and keeping the oil from being sucked out.If the occasion were to arise again to resolve this issue for someone else or use this set up for myself I would stuff the street elbow with SS chore boy to insure that it would perform the function of a separator/baffle.

The reason the 2 I reffered to earlier didn't work is because they had just drilled a hole in the intake, inserted a grommet and stuck a regular 90* pcv valve in the hole which was right in the windage with no way to separate the oil or baffle the valve.

I don't know whether Burger planned it that way or if it was just serendipitous but no matter,if it works,it works.

I'm glad this tech subject and solution came up.It is a good one to file away for future reference.Thanx for bringin' it up man.I love it when the BB hits the slot.

 

The baffle that Scott posted was used in small blocks until 1967. However, 1962 was the last year for the road draft tube. In 1963, Chevrolet substituted the road draft tube with a little "hat" with a nipple out the side. A brass 90 degree fitting was threaded into the base of the carburator. A pcv valve was threaded into the brass fitting, and a hose ran from the valve to the "hat".

 

If there was some genuine interest expressed in doin' it I can fab. some "pcv kits" to work in the draft tube blocks.
Could prolly do some separators too.

 

.......stuff the street elbow with SS chore boy to insure that it would perform the function of a separator/baffle.

Sounds great - where do I get SS chore boy?

Thank you!!

 

How 'bout running a valley pan under the intake?

 

STVBolt,any good grocery store,They are scrubbers they make 'em in copper and in stainless.
A valley pan should work,the question to me would be how would you attach it and would a baffle be easier?It would definitely be smaller.
And.... if the street elbow works,why bother with the others (baffle/valley pan) at all?
I like the street elbow idea it's painfully simple.I wouldn't recommend it to a customer yet,without tryin' it my self, but I definitely see the sense of it now.

 

I read all of the posts for this, and I saw nothing as it would relate to a 350 engine without the road draft. HELP!!!!http://www.jalopyjournal.com/forum/showthread.php?t=159551
I have a 72 350 with the Edelbrock C-26 dual 4 set up and I am running the old no-vent 'Vette ribbed valve covers. I DO have a fill tube from a 66 vette that I am running a vented cap on and the tube has the threaded fitting for the Vette type pcv valve...What do I do to complete the system and where on the block or intake do I hook up what ever it is I need to hook up to? would the pcv valve hose go from the valve connected on the filler tube to the base of the front carb? thanks.

 

if you are going to drill the back of manifold for PCV, why not just use the delectors that come inside PCV type valve covers?

 

Yep, that's what I'm planning to do on my 327 w/o road draft tube, Edelbrock manifold & finned Vette covers.

 

Yo Baby and the others are right about an un-baffled PCV valve into the intake manifold sucking up a lot of oil.

My roadster's 462" Buick has the PCV valve in the same location.
Done by the factory, they bore a hole in a cast boss right behind the carb.

The Offenhauser medium riser dual quad and Edelbrock Performer intake also has the PCV valve in the same location.
I don't remember seeing a baffle under the factory intake - which I ran the first few weeks the roadster was up and running - and the Offy & Edelbrock intakes don't have a baffle either.

What Buick seems to depend on is the combo sheet metal intake gasket/bathtub style valley cover.
This doesn't work as well as it should imo.
Not to mention the cotton pickin' sheet metal gasket doesn't seal off like it should.
I finally got to where I'd run a ring of copper RTV around the water ports and use the liquid blue stuff that came with the gaskets.

Running wide open throttle would result in a very light cloud of smoke, but oil didn't tend to get sucked out and oil consumption was about a quart every 2500 miles.

So . . . fast forward to the tail end of last summer and I started losing coolant - not too fast - starting wasn't as quick as it used to be
Tap the starter and you're running (MSD ignition etc.)

I figured the GD intake manifold gasket was leaking.
Replaced it, same symptoms.
Ran a compression test, #2 cylinder down and coolant in the intake port.

New head gasket, some cleanup and no problem . . . except that I couldn't get the new style intake gasket set - mit rubber rings around the water ports etc. - for a couple of weeks.
Bad deal, cuz right now the 32 is my 2nd car.

I ended up making a set of intake gaskets out of Velumoid .030 thick gasket paper.
An easy job and I figured it would be temporary.

I was going to cut the bathtub gasket down, but elected to leave it off and save it for the new gasket set - which took three weeks to come in and cost almost three times what it should have.

Anyway, the home-made gaskets sealed up great, no water leaks etc.
Bad part turned out to be the PCV valve picks up lots of oil and when at full throttle leaves a cloud of oil smoke that would make a crop duster proud.

In my engine I don't think a baffle by itself would do the job and I was a touch dumb for leaving the bathtub out.
Maybe the baffle and bathtub would do it, but I elected to build an oil/air separator gizmo and it should be done and installed in a few days and I'll report back then.
Somewhere in here the bathtub goes back in and I'll use my gold-plated gasket set.

Down the line, I'll probably end up making my own intake gaskets and cutting down the slightly used intake gasket/bathtub combo's I have left over from manifold swaps and the like.
I figured long ago there would be a good use for the bathtubs if I could ever find a decent intake gasket.
Now that they finally make one I've found that a home-made one works fine.

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One thing I woud like to point out to those who are using unfiltered caps and breathers is that you're pulling dust laden air into the engine.
Not good.

Arrange your fresh air source so that it's getting filtered air.
A small K&N style filter - big enough to do the job - works fine, but the best is to pull air from within the air filter.

One interesting thing about PCV systems is that they were a speed secret back in the day.
That makes them 'trad' in my book....

 

Do you need a fresh air source? Can you leave the system closed and just add the PVC? If you tap the top of the fill tube, install the PVC there and cap the top do you still need a baffle?

 

If the PCV is pulling fume laden air from a sealed engine keep in mind that the crankcase et al is under a vacuum.
And if perfectly sealed there won't be much air - fume laden or not -moving.

A vacuum will pull in air from somewhere, more than likely in the pan gasket area and other places as well.
Un-filtered air I might add.

And if the cap at the top of the fill tube is open to the atmosphere, the only air that'll be pulled through the PCV is in the immediate area and the crankcase air won't be evacuated.

Note that in most cases, the fresh air ingress point is away from the PCV location as far as is practical.

 

I was shown by an old mechanic another way to do this without cutting up anything. i'll draw a picture and get it up here a later today. it uses a 68 firbird 400 pcv valve.

 

to C9: would you give me some feedback on the above please?...my 350 has no hole in the block for a road draft tube...just the port where the pressure sender lives....the manifold has a tapped hole on the verticle riser on the side of the manifold directly under the rear carb base...pictures attached. thanks.

 

just a note on this subject, as a ford tech ,i remembered the efi 5.0s have the pcv in the intake , with a nifty drop in baffle/filter. ill grab one and shoot some pics of it. it is a stainless steel based with a steel cage and 1 1/2 inch diam. and sits in the intake with a grommet above that the pcv sits in.

 

dammm this looks like one of those on going threads about whos idea is better

well i went to roundup this past weekend with no pcv and a moonstyle breather on carb side of each valve cover

man i got into traffic saturday evening and i pucked smoke out the breathers and one the way home (65 to 70 mph on highway) saturated the windshield and firewall with oil ......so its getting a pcv valve soon in intake with the street elbow packed full of ss chore boy

shit i gotta do something been building this car for way to long to put up with this shit

 

I"am wiyh CHOP OLDS here . You have to put the pcv in high spot in eng to work properly and baffle is IMP

 

Interesting that this came around again.

Here's an article I posted some time back along with a report on how well it works after an extended road test.

http://www.jalopyjournal.com/forum/showthread.php?t=251619