Stock air filter too old?

[koneall]

I have a 1967 bug with a newish 1640cc DP stock engine. With the original oil bath air filter. I noticed with the engine idling when I lifted the oil bath off the carb there was a "whoosh" of sound as if I'd removed an obstruction to the air flow. Could the big filter top collect enough debris after 50 years and need to be replaced? Is it possible to find another top?

TIA

crvc

[Eric&Barb]

Any type of good air filter is going to cause some restriction. As long as you replace the oil in the filter as instructed in the Owners Manual it is completely self cleaning.
On the other hand if you are using too thick of oil for the weather you will have more restriction than needed.
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[thomas.]

I just bought a used oil bath filter for a type 2 and cleaned out the top filter part with brake cleaner fluid. I ended up using a whole can. I cut the side off a flat sided jug and use it like a parts cleaner. It finally started to drip clean fluid at the end of the can. let it drip dry at least overnight.
I only cleaned it because I'm going to paint it. The one in my bug I've never cleaned. Like Eric & Barb said it shouldn't need it.

[61SNRF]

I would imagine a '67 would have a similar "element" as an earlier ACL...

Looks like Coco fiber to me, same as seat padding?
Not sure if it was treated in any way or not either, perhaps the oil just wicks up into the weave by natural capillary action?

I'm curious too as to what can be done to recondition or restore them.

For '67- Late models, OG EMPI probably came up with the best idea, which is a custom top cover and a replaceable element that fits the stock housing...

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[koneall]

[tasb]

My understanding is that the oil does not clean the air it is a trap for the dirt particles. The oil does not wick up into the upper reaches of your filter. The air gets channeled to where it passed down towards the oil and then up where the dirt particles are dropped into the oil. I'm not sure that the filter should be described as self cleaning there is a procedure in the Bentley for cleaning them.
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[Eric&Barb]

The top portion of the air cleaner is cleaned by the oil in the bottom portion. The air being sucked over the oil, splatters oil up into the upper part.

The below from the 1967 Beetle Owners Manual.

Note how the upper part only needs hand cleaning if someone runs the air cleaner too long filling it with dirt or without adequate oil in the bottom.
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[VOLKSWAGNUT]

First you need to know how an oil bath air filter works....
The majority of cleaning work is done by the oil...
The incoming air passes through the oil first and traps the dust.

The fibers are there mainly to disperse and block any liquid from entering the intake and carb.

The oil does the majority of work.. and any oily air and dust that makes it through the oil generally is trapped in the continuously re-wetted fibers which will drip back down into the filter sump when the engine is off. Hence why it gets so sludgy so fast.
Its very important to keep the oil level in the filter clean and the correct level..
The fibers can be washed and swished out in a bucket of diesel fuel or kerosene. That's the cleaning procedure for typical oil bath cleaners.
My problem is most of these nut fibers are starting to show there age.. due to non use (dry)
There is no problems with repacking accordingly it with more fibers or an alternative such as steel wool or a plastic mesh, provided you have time as trying to pack these through the intake perforation is a pain.... and taking them apart usually destroys them. The correct amount of packing is important as well..... too much restricts, too little wont disperse/block...

Finding good wet used ones at the swap meets.. is the best

With that being noted... you can gain some MPG, power and efficiency with a replaceable paper filter.
The other side of the coin... an oil bath air filter is a 100% re-useable and serviceable filter and does a pretty darn good job.

I agree the EMPI top was the ticket.. Better filter, and yet retain all the preheat functions.

Basic oil bath operation, follow the air path...

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[Eric&Barb]

Diagram is a bit backwards. Dirty air is sucked into the the air cleaner inlet, down around the filter element, across the bottom to the holes underneath and over the oil below, up thru the filter element, then down the center shaft into the carb. The center shaft of the filter element and the shaft of the outer filter are O-ring sealed to each other.
The cone shaped tin attached to the filter element acts as a slope for waves oil oil to be formed by the air being sucked in over it. These waves constantly wash the underside of the filter and cause oil splatter. Below the cone is a layer of very still oil where dirt from the air collects.
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[VOLKSWAGNUT]

[Eric&Barb]

Also keep in mind that with the oil bath being self cleaning, you do have to change out the old dirt filled oil.

Were the paper air cleaner has "X" amount of tiny holes, for each minute you run the engine "X" amount of holes are being plugged up with dirt/dust right out of the air. Yes, while you can use pressurized air to push out much of the dirt/dust back out of the holes, a certain amount of the holes will not clean out. As time goes more and more of the holes will not clean out making for more and more air restriction.

The oil bath being self cleaning means you always have same air restriction.

A lot of folks found that out here when St. Helen's MT. blew its top. Those with paper air cleaners had them clog up quickly from all the fine dust all over the roads and ended up running the engines without filter. Which soon damaged them.
Those with oil bath filters just dumped/wiped out the old oil and poured in some new.
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[herbie1200]

[tisius]

A proper quality paper air-filter lets air flow through quicker than a more traditional stock oil bath air-filter, while filtering action should be roughly the same.
You do need to replace the paper filter every once and a while.
More air to engine in the same time period = better performance.

However, in very sandy/dusty areas I would prefer to keep the good old oil bath air-filter (and as the original Volkswagen manual says: renew the oil in the oil bath filter more frequently in sandy/dusty conditions).
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[Bret2094]

It works like a bong mann

Bret
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1959 baja beetle ragtop( going back to Full body)
1959 beetle
1960 Beetle frame Custom buggy
1962 Karmann Ghia
1967 beetle( august 66, first car)
1967 beetle (parts car)

1977 Westfalia Camper

1972 Plymouth Duster

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[koneall]

This is the air cleaner I've used for 8 or 10 years. I had added a port for the tube that goes under the left cylinders. You can see the patch job from closing the port. The engine lid kept crushing the tube so I found a spout at Ace Hardware instead.

If I soak the upper piece in diesel overnight, how do I get rid of the diesel soaked into the fibers?

TIA,

crvc

[Eric&Barb]

A tiny amount of diesel should not affect the engine. Just drain it out over night.
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[VOLKSWAGNUT]

[bill may]

[jzjames]

So are you saying the intake air actually passes through liquid oil?

The way it was explained to me is the intake air, with it's accompanying dirt, is sucked down through the aircleaner center tube and then reverses upward into the carb. And in the process, the dirt particles being heavier than air continues downward into the oil and is trapped there.

[Erik G]