[60sstuff]

I get questions sent to me (I suppose because I own a 66 with the code 614 set up) via email, text, pm, etc. about what is OEM correct for the Air Cleaners and related plumbing on the California sold new 64-65-66 Tri-Power GTO's. I'll attempt to share what I know about this topic.

The system has at least two titles, maybe more;
PCCCVS = Positive Closed Circuit Crankcase Vent System
CPCV = Closed Positive Crankcase Vent


I am no expert but because I have always found these cars interesting, unique and rare I have researched any and all cars, plus their related components that left the plant with this system. It's a topic for me that's fun and one that is confusing to most since the factory application of code 614/K24 (64-65) and 614/616 (66) were few to begin with and most all have been altered (air cleaners, pipes, hoses, caps and clamps) over the decades so there are few remaining examples intact.

The 614 (Sales Code) and K24 (UPC Code) are the Air Cleaners Only with sealed oil fill cap. The 616 (1966 Only) was the above Air Cleaners and A.I.R. = Exhaust Smog System.

This thread was started in the 64-65 Tech section but also includes the 66 model year for obvious reasons. I'm only speaking of the Tri-Power GTO's for now.

Starting on Jan. 1, 1964 all Tempest Series models sold new in California were to be equipped at the factory with a special air cleaner system and a closed crankcase. The Tri-Power GTO's had modified air cleaner bases with the two ends being fitted with a single pipe and the center base fitted with a T pipe fitting. Two small hoses #9784235 connected the end bases to the center base on all the 64-65-66's. A black painted steel vent pipe #9776773 for (64-65) and a molded vent hose #9784820 for (66) connected the center base to the LH valve cover.
For 64-65 the LH valve cover had a small hole stamped in it to accommodate a rubber grommet #9776721 for a snug fit of the vent pipe. 1966 utilized a sealed chrome twist in oil fill cap #6421919 with a swiveled nipple for it's rubber vent hose to clamp to as the RH valve cover was blank. The "sealed oil fill caps" for 64 and 65 were on the RH valve cover. The 64 cap was the chrome AC "Top Hat" style that pushed down onto the oil fill tube. The 65 cap was a chrome flat twist in style that was stamped AC in the center.
As you can see every year was a little different but they all served the same purpose to help control and suppress crankcase gases entering the atmosphere.

There is more to this whole system workings but I just wanted to provide the basics for now.

Please feel free to critique my findings and add valuable information or photos of Original CPCV systems.

[60sstuff]

Photos of an Original 65 example owned by a fellow forum member. This 65 was built at the Fremont, Ca. Plant.

[60sstuff]

Unique because the fine gentleman that purchased this GTO new purposely ordered the Calif. style Air Cleaner System even though his car was built at the Baltimore plant and sold new in Virginia.

Just goes to prove that you could order just about anything back in the day!

Awesome Survivor!

PS - Thank You for providing cleaner air for all of us back in 65!

[60sstuff]

Built in Fremont, Ca. and sold new in Livermore, Ca.

[60sstuff]

The above mentioned 64-65-66 GTO Tri-Power cars optioned with the code 614 Air Cleaners and Closed Crankcase are rare. Just as rare are the 1966 Calif. Tri-Power cars coupled with a manual transmission (WV).

The 66 (WV) GTO's which sold new in Calif. had much more under the hood. Two codes were tied to these cars (614 and 612). The above 614 along with code 612 (AIR INJECTION EXHAUST CONTROL) added up to 616 on the Car Billing History.

The A.I.R. cars, referred to as Smog cars had the pump, brackets sealed to both cylinder heads, pipes and hoses plus a unique air cleaner.

This complex unit also used a different center carb with a steel vacuum line coming off the lower right front.

[60sstuff]

The one of a kind 66 GTO with A.I.R. air cleaner. A small foam filter was placed inside the round plastic AC air cleaner housing.

Also a look at the center carb with steel vacuum line that came on the 66 WV cars.

[Tom Vaught]

Great Pictures, Thank You very Much.

Tom V.

[60sstuff]

Originally Posted by Tom Vaught

Great Pictures, Thank You very Much.

Tom V.

You are very welcome!

Pictures of the real OEM stuff speak a thousand words.

[Zimtok]

Where/how did the pumped air get into the exhaust?
I see the pipe that comes forward and down between the pump and the block it then seem to slit and connect to the pump mounting bracket and some other mounting bracket on the other side.
Does it have special manifolds that the mounting brackets pass the air through to?


.

[Tom Vaught]

If you look at the center picture (post #5) you will see a cast passage directly below the Valve Cover lower edge. There is also a cast adaptor mounting plate on the front of the heads.

I believe the air went into the adaptor plate, traveled thru a cast in void, exited the plate into the open cast passage, and then traveled down that passage with air being introduced in each of the drilled passages going to the exhaust ports (shown in the same picture). The passage was plugged at the top surface after it was drilled from the feed passage to the exhaust port.

Tom V.

[60sstuff]

Originally Posted by Zimtok

Where/how did the pumped air get into the exhaust?
I see the pipe that comes forward and down between the pump and the block it then seem to slit and connect to the pump mounting bracket and some other mounting bracket on the other side.
Does it have special manifolds that the mounting brackets pass the air through to?.

Special aluminum brackets bolted to the front of each cylinder head. A portion of the underside of these brackets were hollow (third pic) and sealed with gaskets when bolted to the front of the heads. Round steel pipes pushed into the upper side of these two brkts. through an O ring. A factory threaded plug would be removed (last pic showing installed plug on a Non-A.I.R. car) to allow clean pumped air into exhaust chamber as shown (red arrows) in the factory illustration below.

This Pontiac design was much cleaner looking than the unsightly exterior metal tubes plugged into the heads that Chevrolet used.

[60sstuff]

Another component of the crankcase ventilation that varied year to year / model to model was the plastic PCV hose connectors with the part number molded into it.

64 and 65 Tri-Power used the same "F" connector (#544778). Most were a milky white plastic but I have seen metal versions.

66 Tri-power No A.I.R. M.T. and Auto used (#9784831)

66 Tri-Power with A.I.R. M.T. only used (#9784771). Because of the limited numbers built and the weak design (easily broken) this version is extremely rare!

[60sstuff]

Because of the quirky action of this new 66 Tri-Power A.I.R. Smog System customers were experiencing some backfire situations that in rare cases produced a under hood fire.

I had the privilege to talk with a gentleman that is now in his early 90's that worked at a Pontiac dealer in Salinas, Ca. in the mid 60's. He vividly remembers seeing a few of the Tri-Power cars with the A.I.R. come in after a under hood fire. Pontiac quickly came out with a recall for the owners of these 66 (WV) GTO's to have flat bronze screens installed on the top (between the bottom base and air filter) of all three carburetors to help eliminate any fires as shown on a Calif. A.I.R. unit in first pic. He told me that the service department automatically installed these screens on any Tri-Power car (A.I.R. or not) that came in for service just to reassure all customers.

My 66 (second pic) had these old dirty screens on it when I purchased the car and mine "is not" an A.I.R. equipped model.

Some NOS in the AC box 614 / 616 style air cleaner assemblies were packaged with this screen.

[geeteeohguy]

Chris, my Fremont built but sold in Washington state T.P '65 has the metal F-fitting. And, of COURSE you would have new-in-box tripower filters and screens!!! LOL....great thread, as usual..............
Jeff

[John V.]

Chris, I feel fortunate that my '64 GTO built at Fremont and sold new in Fresno was built in Nov. '63 so did NOT have the Cal closed system.

The original PCV system not only was a great system for capturing fugitive emissions especially for a new "tight" engine but IMO actually enhanced engine performance by utilizing engine vacuum to positively suck crankcase vapors out, thus extending oil life and engine life.

Relying on the old draft tube concept in stop and go traffic was very inferior. I have often thought that the PCV system would have been designed even if emissions was never a concern just because of the benefit to engine life.

I'm not sure of the percentage improvement in terms of emissions but pretty certain the closed system netted a much smaller emissions improvement vs. the PCV system.

Plus the closed system was arguably a negative to engine performance and/or created a bigger maintenance headache than the PCV system alone.

Despite this, today I think they are cool to see and understand. While my own car will remain correct without the closed system, thanks for delving into the subject.

Always cool to study the details. Thanks for providing in depth info for this topic.

My interest is the '64. You've covered it very well here.

I can only add a couple tidbits.

The original p/ns for the '64 center base to end base rubber hoses was p/n 9776772. I think the hose p/n you posted (9784235) must have been a superseding p/n, I'm guessing it was released in or for '66, much too new a p/n to have been original for '64.

There was also a small rubber hose in '64 connecting the vent pipe coming from the LH valve cover to the center base, p/n 9776770.

In production, the Assembly Manual instructed the plant to remove the valve cover rubber grommet plug and the regular oil fill cap and return them to Stock Inventory when installing the closed system.

Interesting to learn that they had some issues with fires. My understanding is that PMD engineering provided for a spark arrestor with the original '64 set-up, anticipating the potential for a backfire thru the carb. I thought this was a filter element in the air cleaner.

Not familiar with the details of it but if true, you might expand on that part of the system as you add to this thread.

Great job!

[60sstuff]

John, I supplied the part numbers from the below parts book pages (revised 7-1-66)

64-65 T/8 3/2 B.C. GTO HOSE, center to end bases w/closed cc vent (2) 9784235

66 same HOSE shows same part number (2) 9784235


I have a question?
I know the CPCV "center air cleaner base" was different for two reasons (opening for air horn and the T pipe fitting was different) between 64/65 and the 66 model year.
I have always thought the end bases with pipe fitting for all three years were the same but the part numbers are different for these??

64-65 frt. and rear w/closed c/c vent (2) 6420767
66 same (2) 6424293

Is there a physical difference in the CPCV end bases?

Sorry for the small attachments.

[John V.]

Yup, definitely a superseding p/n for the 9784235. In the original release of the '66 MPC, the line item for the '66 application is missing altogether (apparently an oversight).

And the line items for the '64/'65 GTO application and the '65 421HO application both listed the 9776772. Unfortunately I have no idea if the length of the hose changed or if there was any difference besides a p/n change.

On your question about the Gr. 3.402 Air Cleaner & Silencer, I don't have any definitive answers, possibly more confusion to add to the mix.

From what I can tell, the Air Cleaner & Silencer included the base & the cover since they did not service these items individually.

The '64 p/n for the Air Cleaner & Silencer without closed crankcase was originally p/n 9776766 for all carbs.

You will note that the '64 p/n was superseded by the '65 p/n 6420482. In my book this p/n was only for the '65 application, the '64 p/n not yet superseded.

I can only guess that the original '64 p/ns for the closed system were 6420767 & 6420768 respectively and carried over to '65. Without a '64 Parts Book to check, I am just guessing on that, there could just as easily have been specific '64 p/ns that were already superseded by the '65 p/ns.

As you say, it is obvious that the '66 center carb needed a different assembly.

But why did they issue a new p/n for the '66 end carbs if there was no change in the physical part?

It may be that they simply issued a new p/n for the same part just so that the p/ns remained in a "grouped" sequence.

If that was the case, you would think they could have superseded the '65 p/n and replaced it with the '66 p/n.

Maybe they eventually did, could have been a simple oversight that it had not yet been superseded in the Parts Book as of your revision date.

But here is something perhaps even stranger.

In my issue dated Oct 1, 1965, the '66 applications list a different p/n than what is shown by your revision.

The center is p/n 6422195.

The end carbs used 6422194.

The non-closed crankcase 3/2 unit was p/n 6422193.

Was there an early and late '66 3/2 Air Cleaner & Silencer assembly? I sure don't know.

Is it possible that the screens you mentioned were added to the assembly and new p/ns created for them? That would make sense to me.

But wouldn't explain how either set of '66 p/ns differed from the '65 or '64 counterparts for the bases and covers (if they differed at all). If the addition of the screens was the reason for the later '66 p/ns, still would leave it in doubt as to why the early '66 end carb assemblies needed a new p/n.

[60sstuff]

I wonder if this had anything to do with part number changes in regard to the air cleaner bases? No big design change, but maybe enough to warrent a different part number?

After a closer look at my assortment of OEM air cleaner bases I see that a 64-65 (Option #614) set I have shows a noticable difference (on end bases, 3rd pic, red arrows) from the NOS 66 end base design shown.

The 64-65 inner rolled lips are fatter than the thin roll 66 end bases.

64-65 End Base (2) #6420767
66 End Base (2) #6424293

[Option 382]

They did that for one of 2 reasons.

1. Early GTO had more sucking power in the carbs and they had to reinforce the bases to prevent the vacuum from collapsing them vs the 66.

2. The 66 was a heavier car and they had to start cutting the weight down somewhere else.

Just kidding. Just picking on 60sstuff since he has a 66.

[Baron Von Zeppelin]

They were trying to slow the 66's down so GM wouldn't lay the smack down on multiple carbs .

Was too late.
All those 66 Chevelle SS 396 buyers had already written too many letters of complaint against the 3x2 66 GTO's being too superior.

One SS owner even wrote "at least the tail lights on the 66 GTO are neat to look at" .

Was good while it lasted.