Please ID: oil bath air cleaner

[Hanno Spoelstra]

Who can ID this "United Oil Bath Air Cleaner"?

Thanks,
Hanno

[Phil Waterman]

Have a couple of thoughts but need something to gauge size. What is the bottom throat size?

If it is a CMP part I would suspect that it is a crankcase ventilation inlet air cleaner.

Cheers Phil

[Keith Webb]

It is indeed the crankcase breather filter for a Ford Cab 13 and it sits at the rear of the engine where the fuel pump is attached.

[Grant Bowker]

Based only on the size of the wingnut on top compared to the body of the filter, I had been wondering if it was for a small engine like the chorehorse generator. I'm glad to see an answer for the application.

[Tony Smith]

It's all that, and more!

The Ford V8 used a wire gauze breather cap (part no 48-6766B) used at the top rear of the inlet manifold, a standardised design that was introduced from the 1934 model and used right through to 1948 on cars and trucks. The wire gauze was an effective filter to prevent wasps getting in the engine, but little much else smaller, even with the gauze dampened with oily blow-by. In 1941, a Service Bulletin announced that a Oil Bath filter was introduced for "Heavy duty service in dusty conditions". I'll go out on a limb here and suggest the standard breather was fine for the paved roads of Detroit or Windsor, but following experiences in North Africa, where Ford engines were required to be rebuilt after as little as 1000Mi due to "dusting" and wear, something was needed that actually filtered the air going to crankcase.

United Specialties made a small air filter that was in use at the time on small engines such as Waukesha, Onan and Wisconsin. This filter had a flat base and was screwed onto the flange with a thumbscrew. Ford released this filter as a stopgap measure as C11AS-6766C, but it required a new filler pipe to accept it, C01Q-6765D. This pipe was offset to allow the larger diameter of the oilbath filter to clear the firewall on the C11ADF wagons and standard cab '41 model trucks, and the engine cover on 12 Cab CMPs. A later version (C11AS-6766B) was modified to use the bayonet fitting of the 48-6766B cap, allowing it to use the standard filler pipe, as there was also more firewall clearance on 1942 model cabs and the 13 cab CMP.

[Hanno Spoelstra]

Originally Posted by Tony Smith

United Specialties made a small air filter that was in use at the time on small engines such as Waukesha, Onan and Wisconsin. This filter had a flat base and was screwed onto the flange with a thumbscrew. Ford released this filter as a stopgap measure as C11AS-6766C, but it required a new filler pipe to accept it, C01Q-6765D. This pipe was offset to allow the larger diameter of the oilbath filter to clear the firewall on the C11ADF wagons and standard cab '41 model trucks, and the engine cover on 12 Cab CMPs.

Tony,

Thanks for this excellent information plus photos!

So now I need to get a Cab 11 or 12 Ford to go with this filter . . .

Hanno

[NORTH-SHORE(CANADA)]

Originally Posted by Hanno Spoelstra

Tony,
So now I need to get a Cab 11 or 12 Ford to go with this filter . . .

Hanno

Hi,
It cheaper to buy a order Oil Bath Air Cleaner thans buy a Cab 11 or 12

[Keith Webb]

I thought this was the normal cab 12 one on the gooseneck.

[Tony Smith]

That IS the standard breather (48-6766B), as found on the 12 cab. You couldn't use a bayonet style Oil bath cleaner because of the angle it's tilted at, the oil inside would not sit level. The Swan neck pipe I pictured above was actually removed from a 12 cab truck, and had me baffled until Chris Vickery was able to provide me with the filter. I had previously picked up a bayonet Oil Bath filter, which came off a 13 cab truck.

The Service Bulletin amendment came out in 1941 and was not just specific to CMP trucks, but covered all Ford V8 vehicles in dusty conditions. It is of note to record that although the United Oil Bath air cleaner is made in the USA, the Service Bulletin and part numbers indicate that this is a Canadian modification (presumably following Commonwealth experiences in North Africa) and I have not seen any US manuals showing the fitment of the Oil Bath filter to US cars or trucks.

[Hanno Spoelstra]

Originally Posted by Tony Smith

The Service Bulletin amendment came out in 1941 and was not just specific to CMP trucks, but covered all Ford V8 vehicles in dusty conditions.

Here's one still in situ on a 1943 Ford 3-ton Fire Lorry as delivered to the R.C.A.S.C.

[Hanno Spoelstra]

Originally Posted by NORTH-SHORE(CANADA)

It cheaper to buy a order Oil Bath Air Cleaner thans buy a Cab 11 or 12

Yes, but having this particular oil bath air cleaner is a very good excuse to buy the "missing bits" of a Cab 11 or 12 Ford

[NORTH-SHORE(CANADA)]

Originally Posted by Hanno Spoelstra

Yes, but having this particular oil bath air cleaner is a very good excuse to buy the "missing bits" of a Cab 11 or 12 Ford

Hi,
Hum...... your right

[cletrac (RIP)]

I didn't think you needed an excuse to buy a cab 11.

[George McKenzie]

Dave I see on your list of CMPs that you only have one #12 .What I was wondering was is there not many # 12s made ? There was a site that talked about this crankcase filter some time ago . PS It is going to -30 C here again .Global warming is not a very good subject to talk about in this part of the world. .

[Hanno Spoelstra]

Originally Posted by Tony Smith

A later version (C11AS-6766B) was modified to use the bayonet fitting of the 48-6766B cap, allowing it to use the standard filler pipe, as there was also more firewall clearance on 1942 model cabs and the 13 cab CMP.

I guess this is the C11AS-6766B in situ on a late model Winterized Ford F60L. Apparently they were not exclusively for dusty/ desert conditions?

[Hanno Spoelstra]

Once you start looking you see them everywhere….