Re: An Air Cleaner from a '33 - To Clean or Disassemble

Posted by Don Shields On 2014/8/18 11:56:52

This thread has been a real eye-opener for me. I didn't know that these air cleaners are oil mesh. I read somewhere years ago that there are passages inside the cleaner that cause incoming air to change direction several times before reaching the carburetor, and dust supposedly falls out of the air as it is changing its direction. So I didn't know it could be serviced.

Concerned about inadequate air filtering, over the years I tried different foam rubber overwraps around the louvers, but they all collapsed when accelerating and starved the engine for air. I also tried the Honeywell room air cleaner prefilter material, but that wouldn't stay put on the cleaner when roadtested.

The servicing instructions seem kind of primitive to me. Swirling it in gasoline, diesel fuel, or paint-removing mineral spirits looks to me to just generate a disposal problem: How to get rid of 4 to 6 gallons of dirty gas, diesel or mineral spirits. Also, doesn't it drip oil onto the manifold and generator after re-oiling by dipping?

If a pleated air filter could be found that would slip over the louvers, that would be a better way to go. Unfortunately, most filter manufacturer websites do not list their products by size. Except K&N, they have a search feature that takes your I.D., O.D. and height parameters and lists what they offer that's closest to your input size. The louvered section of our air cleaners measures about 5 1/4 inches in diameter and the cleaners with ten louver stacks are about 3 1/4 inches high. K&N makes a filter to just that size under their part number E-3340. I see from the photos that some cleaners have six louver stacks; K&N makes 5 1/4 I.D. by 6 1/4 O.D. filters in heights ranging from 1 1/2 to 6 inches, so there's bound to be one that fits these also. No local auto supply store will stock this size, so I ordered it from K&N; they had it in stock. These filters are cleanable with water and reusable. They recommend cleanings at intervals up to 50,000 miles so it should be quite a while before our low-mileaged classics would need that.

The filter slips on easily over the louvers and seats on the flange at the base of the louver stacks. There is about a 1/8 inch gap at the opposite end of the louver stacks that could permit air to bypass the filter; I sealed that with silicone. Those who show their cars competitively might want to devise a different sealing method, perhaps a foam rubber ring that would be easily removed when on the show field. There are no clearance issues nor were there any drivability issues found on a 15 mile roadtest.