Oil bath at the time was the best way.  I don't think the D17 had a dry filter till the series 3.  Maybe 4.  Series 2 is for sure oil bath.  Some say it's still the best at filtering air.

AaronSEIA

Thanks, my ?? was mainly "was there no dry filter" technology previous to the mid 60's 

dang, I'm supposed to clean my air filter ??? lol...

'somehow' I have a complete spare unit for my D-14s..

no air filters on snowblowers.....btw

I've seen on some tractors, mainly pullers, where they have installed a paper filter in a cone shaped holder, with a rubber tube going to the carb.    Wouldn't that allow less air in?

When I was a kid we never had the air cleaner hooked up on our WC.  It was our primary tillage tractor.  That thing ran like a tank.  I started driving it when I was 10, and we had it a few years before that, and we were still using it when I left for the AF at 19. 

It was a narrow front tractor and we had to drive it across the creek to get to other fields.  One location we had to drive up a steep bank at a diagonal.  That tractor never tipped over going up that bank, but it sure made me nervous. 

Apparently, at one time, Ford felt oil bath was superior to paper filters. Way up into the 70s they offered an oil bath option for their heavy trucks that were used under heavy dust conditions.

Robert Musgrave wrote: There are no Air Filters on snow blowers because there is no dust in the air during use!  However, carburetors have additional shielding because of snow melting and turning to ice/water.  Also notice how sheet metal goes around the muffler to help "pre-heat" air for intake/carb. protection.  R. Musgrave

Dust IS significantly lower when conditions are most likely snow, but the biggest reason, is that a snowblower, in operation, melts significant snow, and incoming air of the process is always extremely humid.  Apply a paper filter to a working snowblower, and you'll have a frozen filter in very short order.

The filter's job is to prevent abrasives from causing rapid internal engine wear... and any engine operating within 3000ft of the ground will be swallowing dust.  If you're wondering how abrasive soil is, look at the moldboard after you've pulled two rows... or fire up your chain saw, take a test cut in a tree limb, then stuff the nose of the bar into the dirt at full throttle, and try again... it'll be dulled instantly.

The oil-bath air cleaner is substantially more effective, at a lower restriction, than a paper filter of the SAME FILTRATION capacity.  Although it was much higher maintenance than a paper filter, the oil used in the bath need not be 'new' oil... it was often reclaimed from the crankcase.

The sump of An oil-bath filter will naturally allow atmospheric moisture (condensation) from both outside, and inside the engine to fall to the bottom, just like the sediment bowl under the fuel tank.  As long as that sump doesn't fill completely, the oil-bath filter will be just fine... but if it fills, and the ambient temp falls below freezing, the engine won't start. 

The reason why the oil-bath filter went away in automotive, and the paper filter took over, was because the automotive application didn't work as hard as the agricultural, didn't work in as dusty an environment, and didn't need to last as long.

Neither my '24 Model T, nor my '29 Ford A pickup have ANY air filter... but one COULD purchase one for the A as an accessory.... but disposable paper filters weren't particularly known then.  Instead, the filter consisted of a wire basket, around which one would wrap oil-dampened cotton cloth.  It was necessary to make regular mixture adjustments to compensate for the restriction, but on a Model A, one simply reached over to the passenger side and turned the choke knob a little.

Neither the Model T, nor Model A Ford had air (or oil) filters, as the leader's 'edict' stated neither 'needed' air filters. It was considered acceptable by the designers for these engines to get 'minor overhauls' averaged every 4 to 6,000 miles... about 250 hours.

As time went on, longer intervals became expected.  Military engines fitted with filtration proved the concept to millions of GIs.  Metallurgy improved, and protective plating processes appeared.  Adding filters was a simpl, quick and easy way to extend the MTBOH... and the manufacturer took advantage of the circumstance by up-selling dealer service to include filters into the oil change package.  To improve the margin even more, they invented specially-fitted filters so that a 'standard industrial' filter system couldn't be used... and then contracted major manufacturers with 'sole source/exclusive sourcing' contract to make the special filters available only through dealers, so that aftermarket supply wouldn't exist.

Which sounds suspicously familiar... and I hear the song "everything old is new again'  playing in the background...

 OUCH !! what was the "protection" for them ??

If memory serves, dad ran a '65 flare-side 4 speed stick that hauled 1000's of hogs/1000's of bushels of ear corn to the local elevator that RAISED the front end of the truck to dump into the "pit"  !! Thanks for that memory  !!