[Tom Vaught]

Sometimes it is very hard to determine a PCV Valve for your PONTIAC ENGINE
when the Valves are no longer being services.

I have some flow numbers and part numbers for a few Ford Engines that could be used to determine what your engine likes.

EOTE-6A666- A2A Gray Minimum Flow= 1.3 cfm Maximum flow 3.6 cfm

D9BE-6A666- C2A Black Minimum Flow= 1 cfm Maximum flow 4.05 cfm

D8ZE-6A666- A2B Black Minimum Flow= 1.55 cfm Maximum flow 4.6 cfm

D80E-6A666- B2A Black Minimum Flow= 2.7 cfm Maximum flow 4.6 cfm

The 1st three valves are for 4.6L 4 Valve (281 cid) High Performance engines

The 4th Valve is for 5.8L Push Rod engines

The highest flowing valve in the large list (which I did not post) is the:

E7TE-6A666- A2A Black Minimum Flow= 1.65 cfm Maximum flow 4.75 cfm
This valve was used on 5.0L Truck applications.

All of the valves SHOULD BE configured similar to the Pontiac PCV valves.

These valves would be to help dialing in your crankcase corrosive gas removal from the pan and then burned in the intake.

If you have a engine that idles at 16-18 inches of vacuum the 1.6 cfm flow number means nothing when the engine is consuming 18 to 20 cfm of air at idle. Going down the road at cruise the engine might be consuming 350 cfm of the total 750 cfm of the typical engine.

PCV systems really help a engine live a lot longer in a street application.

Tom V.

[Shiny]

Thanks for this, I want to learn more.

How do these Ford valve flow values compare with Pontiac's original parts, how do you determine what is needed? Is there a thread or online tutorial you can point to?

[dataway]

My engine idles at about 21" of vacuum ... not sure whether that is a good thing or not.

When I was looking up NOS PCV valves for my 68 I noticed that one number covered hundreds of GM cars ... all V8's but a pretty huge spread of years, displacement and performance level.

[steve25]

Your motor pulls 21" at what idle rpm and how many cid is it?

Thanks Tom , great info!

[dataway]

It's a 68 YS400 (.040), Qjet, 068 cam, standard logs. 700 rpm .... vacuum will actually increase a tad up to about 1100 rpm.

That's manifold vacuum from the fitting in front of the carb (usually used for driving the pre-heat cans in air cleaner I think). Checked it with two different gauges.

Brand new engine by the way, still on the stand.

[Tom Vaught]

The point of the thread was three things.

A) Actual documentation (specs) for millions of production engines out there.

B) Documentation to show how little PCV VALVE flow is actually going thru the PCV Systems and how little effect it makes to a typical Pontiac Engine.

C) The specs for Minimum Flow (typically around 1 to 3 cfm), and Max Flow thru the Valves less than 5 cfm. The highest flowing valve is 4.75 cfm passing crankcase fumes thru the engine.

Tom Vaught

[Goatracer1]

I converted my 1955 Pontiac to pcv by using a Mopar gray pcv valve from mid 1980's 318. If you remove the draft tube the regular pcv grommet fits in the valley cover. The Mopar valve fits the grommet and the flow works well for the 287 engine. I've used this for over 20 years with no problems. For a vacuum source I tapped the intake and add the 2 vacuum fittings and tee from a 389.

[Tom Vaught]

Well Goatracer1, by doing that 20 years ago, you probably bought your 1955 engine those
extra 20 years plus some. The road draft helped but the PCV system was a smart system.

Tom V.

[dataway]

Would you say in general that for a working PCV at idle ... if it's pulled out of the crankcase and plugged that manifold vacuum should increase 1-2" ? And that if the increase is much less then it wasn't working/plugged, and that if vacuum increase more than 2" that it was flowing too much?

[Tom Vaught]

1) Hard to say on that situation Dataway because the typical IDLE airflow of a 400/455 engine is about 19 cfm. Some engines slightly less.
Very few, unless 500 cid plus, need more idle airflow to idle properly.

2) If the happy spot on the specific engine was say 17 cfm (Pontiac 400 cid engine) and you removed 2 cfm from the idle airflow, then you would move the throttle blades out of the correct Transfer Slot Position (carbs without idle-eze) to keep the engine running and the engine would be unhappy. So now you are playing with the secondary blades of the carb to get the 17 cfm for a happy engine or drilling holes in the throttle blades.

3) The carb calibrations and testing were based off of a Carb WET FLOW stand, and used a fixed orifice (in line on a hose attached to the PCV nipple) to simulate the average PCV contribution added to the Idle throttle blade airflow.

Hope this helps.

Tom V.

[dataway]

Interesting topic. After a couple of searches I found that it's a far more important topic than most people think.

[Tom Vaught]

Originally Posted by dataway

Interesting topic. After a couple of searches I found that it's a far more important topic than most people think.

Some people just ignore info if they do not understand what that info actually means. It is refreshing Dataway, that we still have individuals who read something and then on their own time do further research on the subject.

My hat is off to you.

Tom Vaught

[Torquewar]

Thanks for the Post Tom . Nice to have flow rates and part numbers. It helps a bunch , just one of those small parts in the system that really should be looked at..

[dataway]

Tom, people like me that don't know a lot, have to pay attention

[Tom Vaught]

I was a Carb Guy, who did Boosted Engine projects for Holley Engineering.
I knew nothing about Emissions and F.E. (even though I could run an Emissions and F.E.
RW Dyno and the Emissions/F.E. Test Bench at Holley).

I got the job at Ford working in the Emissions and Fuel Economy organization because I had "Experience" with Emissions Testing, knew about carbs (the 1979 Ford Turbo Mustang had a carb, and a Turbocharger on it. I did NOT do Emissions and F.E. Testing, they had people in another organization for that deal. I made sure the vehicle was Emissions and F.E. compliant and signed off on the calibrations and observed the testing at the EPA.

Because we had to inspect every part on the Emissions system before the vehicle was sent to the EPA for testing, I got to know all of the Emission Components and the Component Engineers for that stuff. The PCV Engineer gave me that info and other info
over the years based on his work. Pure "LUCK of the IRISH" deal on a lot of stuff I post about.

EVERYONE starts somewhere Dataway.

Tom Vaught

[Brian Baker]

How would this information apply to say, a 445ish Pontiac pulling 9" of vacuum at idle?

[Tom Vaught]

Originally Posted by Brian Baker

How would this information apply to say, a 445ish Pontiac pulling 9" of vacuum at idle?

The Chevrolet and Pontiac PCV Valves are interchangeable.

The L-88 engine had a radical camshaft and still used a PCV valve.
Same deal for the Z-28 engines. Same deal for the Mopar applications.

My suggestion would be to look for a PCV valve for those applications.

The Chebby stuff most likely being the most in supply and still offered.

Tom V.

[Skip Fix]

I just pulled up a picture of a Pontiac stocker's D port motor and it has a PCV in both valve covers.

[Kenth]

Originally Posted by Skip Fix

I just pulled up a picture of a Pontiac stocker's D port motor and it has a PCV in both valve covers.

No air into the crankcase?

[Skip Fix]

I'll go back and look for a source. Had some cool Tri Ys on it.