1967 Oil Bath Air Cleaners – A Discussion

Recently, my dear wife asked if all aspects of the 1967 Beetle had been covered through discussion, articles and illustrations.  I had to answer with an emphatic:  NO!

Again and again new subjects arise. Oh, somewhere, someone may have touched on the subject, but there are so many aspects about these great little cars to be investigated!

One recent surprise (to me, at least) was the “discovery” of at least two configurations for the 1967 Beetle, One-Year-Only Air-Cleaner (also called Air-Filter, Air Breather, Oil Bath, etc.)

The Air-Cleaner for 1967 was developed for better fuel-air mixture pre-heating ability.

The Cleaner now utilized two Air Delivery Tubes instead of only one as in previous years.  The Tubes served not only to introduce more air into the Cleaner, but to allow for two Paper Pre-heat  Tubes for the collecting of additional pre-heated air from beneath the Engine.

The pre-heated air enhances the further atomization of the Fuel-Air Mixture which is being introduced into the throat of the Carburetor. 

Of note here, too, is that these Pre-heat Paper Tubes required additional parts for the collecting of the pre-heated air from beneath the engine compartment.  The pre-heated air is collected as Fan Air passes over the Cylinders and is being channeled away from the Engine.  But, that’s a subject for another article.

We cannot over-look the fact that the new-for-1967 1500cc Beetle Engine also required more air for the Combustion Process.

The Air-Cleaner for the 1967 Beetle was given the VW Part Number of 113-129-613F. Unfortunately, for us, the Part Number was not placed on this Air Cleaner at the factory. This causes us, now well over 50 years down the road, some amount of confusion. 

Between this “F” designation, there appears to be a gap between Air–Cleaner models.  The next Factory alteration (which we know about) occurred for the 1968 Air-Cleaner.  It carried a Part Number of 113-129-613J and was introduced during April of 1967.  It never was used on 1967 Deluxe Beetles .

This latter Air-Cleaner kept the two Air Delivery Tubes but combined the two Pre-heat Tubes into one large Pre-heat Intake Tube on the passenger’s side.

We do not know what happened between the “F” model and the “J” model.   Perhaps there were test models which never reached production.  There seems to be no one who definitively can tell us what happened during this Air Cleaner transitional period in VW History.

David Brown scoured his Volkswagen Parts Manuals for information leading to a better understanding of the new-for-1967 Beetle Air-Cleaner. It IS possible that there were variations which were produced solely for application at Dealerships.  However, Air-Cleaners which were being produced for Assembly Line 1967 Beetles appear to have been only the one type—the 113-129-613F.

Now, let’s toss in that “variant” to which I alluded earlier:  an identical Air-Cleaner for 1967 Beetles but one which had Flared Air Delivery Tubes!  Yes—these have surfaced now and then.

Again, I must add that we can find no mention of this Air Cleaner with Flared Air Delivery Tubes in the VW Literature.  David Brown believes that “The Flared design enhances the inlet air flow and so is an ‘engineering change only for improvement’.  These changes  usually were brought to production as soon as possible by Volkswagen and not held up until the next model year.   Unfortunately, not all of these design changes produced a Part Number change.”

Page 46 of the Deluxe Beetle Owner’s Glove Box Manual describes the purpose and care of the Air Cleaner.  It also shows a depiction of a 1967 Beetle Air Cleaner (sans Flared Air Delivery Tubes).

To compound things…some 1968 Air Cleaners also have Flared Air Delivery Tubes while others do not!   Perhaps there were multiple manufacturers—as long as the Cleaners met the specifications set by VWAG,  Flared or not Flared Tubes, the Air Cleaners would have been acceptable.

Now, onto the next interesting side-line.   1967 Beetle owner, Scott Morgan, in searching for a good ’67 Air Cleaner for his Beetle, came upon this one for sale:

David Brown has seen parts to this application, but not an entire installed Kit.  In fact, I had a piece of this Kit on my shelves—but I did not know its application.

As Beetles (and other VWs) became popular, add-ons and kits of all sorts began to hit the market.  Indeed, many of these could be purchased at  VW Dealerships as sanctioned Kits.  Some even bore the VW Logo.  Many, of course, did not.  Catalogs, such as the famed JC Whitney Catalog, and many others, offered the VW owner all sorts of cutesy and even beneficial add-ons. One early “big name” was EMPI, which marketed products which have become highly valued by Vintage VW owners.  (this, long before EMPI went down another road.  The original company closed in 1974).

Scott and I discussed the advertised Air Cleaner.   We agreed that he would be better served if he could find an original 1967 Air Cleaner with no modifications.  It seemed that the Cleaner which was advertised had been altered by the use of a non-genuine VW Part.

Then, Scott discovered an advertisement for a vintage Kit for altering an Air Cleaner.  Since it depicted the alteration to the top of the Air Cleaner like the Cleaner he was thinking of buying, he sent the Link to me.

After reading the ad and looking at preliminary advertisement photographs, I contacted the seller and purchased the Kit. I was eager to see whether or not the Kit had VW origins.  Upon receiving the Kit, I examined the instruction sheet and parts, but could find no mention of a VW Part Number nor any mention of VWAG or of VWoA.  (Volkswagen of Germany and VW of America.

Unfortunately, both hoses and the EGR Valve (Exhaust Gas Recirculation) were missing from the Kit.  Clearly, the original Kit had come with the other parts and additional instructions.

At any rate, a VW owner could have bought and installed the Kit or could have had a shop to do the installation.

The premise of the Kit is to introduce exhaust-heated air into the Air Cleaner.

At Idle and when Decelerating, unburned fuel exits the Exhaust System as a pollutant. Clean Air Standards were tightening in the USA.  A “primitive” Emissions Control attempt already had been made in the years prior to and including 1967.  The Hose from the Oil Filler to the Air Cleaner had been introduced.  Its purpose was to recycle Crank Case Vapors into the Air Cleaner, then through the Carburetor and Intake System to be burned during Combustion.  Crankcase Pressure, along with Vacuum created during the Combustion Process introduced the Crankcase Vapors into the Air Cleaner. 

I have read no studies which show that this was an effective method for reducing unwanted Vapors into the ambient air.  But, it was a practice by VWAG which persisted over many years.

The Kit which I purchased intended to go even further.  It proposed to recycle Exhaust System Gases, which contained Unburned Fuel, through the Air Cleaner, through the Carburetor and through the Combustion Process.  Here’s how this Kit proposed to do the job.

The EGR Valve is a one-way Valve.  Looking at the Diagram, this would be the process.

At Idle and during Deceleration, Unburned Gases were being emitted through the Exhaust.  By capturing this Raw Exhausted Fuel Mixture, fewer Pollutants would be emitted into the air which we breathe.

Higher Vacuum at Idle and during Deceleration, created during the Combustion Process,  is siphoned off at the Carburetor Velocity Plate (now installed at the base of the Carburetor).  This Vacuum exerts negative pressure,  pulling the EGR Valve open.  As the EGR Valve opens, it allows Heated Exhaust Gases to pass from the Manifold Pre-Heat Tube up and into the top of the  Air Cleaner.  This Heated Exhaust Gas passes, along with Engine Compartment Air and Crank Case Vapors through the Air Cleaner, through the Carburetor and thence through the Combustion Process.  This process is continuous, while the Engine is running.

I discussed the Kit and its purpose with David Brown and Barry Blythe—both accomplished Volkswagen Machinists and Engine Builders.  Both agreed that little advantage, if any at all, would have been gained by installing this Kit.   And, certainly no better fuel economy would have been achieved!  It simply was another early attempt at Emissions Control. 

The Kit’s Information Sheet depicts a 1970 Beetle Engine (note also the Air Conditioning Compressor).  For 1968 (and later) Beetle Models, a Throttle Positioner was installed onto each engine at the Factory.  The Throttle Positioner was an apparatus which managed the Deceleration Process.  Rather than to quickly Decelerate when the foot is removed from the Accelerator Pedal,  Engine Speed was slowed very gradually to Idle, reducing the amount of Unburned Fuel emitted into the atmosphere.

The producers of the Kit (described above) thought that their Kit, in combination with the Factory Throttle Positioner and Crankcase Vapors Recirculation Hose would reduce Emissions even further.

Many thanks to Barry Blythe and to David Brown who contributed to my knowledge of early Emissions Control Systems.  (Gentlemen—I hope that I have presented your contributions accurately!)

Scott Morgan did his homework, during which he discovered the after-market Kit which shed more light on an early attempt to control Exhaust Emissions. 

Richard Marcoux provided photo #3a of the Flared Air Delivery Tubes on the Air Cleaner of his unrestored 1967 Beetle.  Thank you for your contribution, Richard!

I am thankful to Everett Barnes for the use of Photos #2 and #4.

Maybe you, The Reader, have further information to share.  This Article is entitled as a “discussion”.  Feel  free to join the discussion to expand our knowledge of 1967 Beetle Air Cleaners!  Note that I have not examined Air Cleaners on any Model other than the Deluxe Model ’67 Beetle.   If you have a 1967 Beetle which was produced for markets other than the USA, we’d welcome information about your car’s Air Cleaner.