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Tue Nov 03, 2020 2:21 pm

Hello all, new to the forum. Recently acquired '73 super beetle, trying to learn as much about the car as possible but working a little blind. My VW has the oil bath air filter system on it, reading some posts on here seems it is recommended to keep that in place versus converting to paper element. My filter housing as it sits on top of the carb is very loose. The clamp for securing it is tight as can be but can literally be lifted straight up off the carb with little to no effort. Is this a normal thing or is there a seal that is wore out making it loose. Thanks

Tue Nov 03, 2020 2:52 pm

If it's like earlier oil bath air cleaners, there is not a seal at the carb top flange. Check that the clamp isn't bent/broken such that it is not clamping when fully tightened. They can get banged up over the years.

Is the steadying bracket missing (E in the manual's photo)?

Tue Nov 03, 2020 3:00 pm

Just looked at the engine, that bracket does appear to be missing. Maybe I can find it on jbugs.

Tue Nov 03, 2020 4:36 pm

Check out this ad:
https://www.ebay.com/i/291441490838?chn=ps&nor...GwQAvD_BwE
Some details changed over the years, but you can probably bend/adapt it.

Or check this one out:

https://www.bugcity.com/shop/shop.lasso?cid=11&...ci_4907573

Here is an engine with it installed, a better view than from the manual:

Details are different over the years, but you get the idea.

It connects to the intake manifold/carb flange at the bottom. It's two piece so the air cleaner can be removed without disturbing the lower part.

Wed Nov 04, 2020 9:40 am

The clamp should grab the carb tightly.
Otherwise it will and flake metal into your engine, thus defeating the purpose.

If you change to a free flowing papwer or other element, you will NEED to re-jet the main jet in the carb. It will be too small.
The oil bath represents a slight restriction in flow. Air actually has to bubble thru the oil (like a bong).
Remove that restriction and the carb will draw more air and less fuel.
Put a 135 main jet in there and you will notice a huge power increase..

Wed Nov 04, 2020 10:03 am

It doesn't bubble through the oil. The fibers in the filter represent a restriction to the air and wick oil from the bath, allowing the particles to be captured. The sudden change in direction causes the particles to fall into the oil rather than follow the flow of air due to intertidal forces. But yes, there is a definite restrictive quality to them by their very nature.

If it's bubbling through the oil you've way overfilled it.

Wed Nov 04, 2020 1:13 pm

Thank you for all of the replies, any advice at this point is helpful. Had always wanted one of these cars but knew nothing about them. I will have to find a better clamp for securing the air filter housing because it is definitely too loose. Not sure what else it needs, learning as I go. I'm feeling its a little underpowered as it struggles to get up to 60mph, maybe just needs a good tuneup. Only has 39,000 original miles on it but much of it looks like it has not been changed in a long time if at all.

Wed Nov 04, 2020 3:28 pm

I've seen a few carburetors over the years where the top flange for the air cleaner wore out. The carb is made of pot metal (cast zinc) which is a bit softer than the steel of the air cleaner, and wear happens there first.

I've alternated between a period 28PICT and a BOCAR 30PICT-1 carb on my 62 Bug. That is with the original air cleaner, and while it barely clamps onto the old 28, I have to loosen the clamp bolt to get it to fit onto the newer 30 carb.

Wed Nov 04, 2020 3:52 pm

My bug is a 73', seems to run pretty smooth at this point, I'm only thinking about doing the tuneup because I have no idea when it was done last so it can't hurt. But something else I've noticed is they don't seem to sell the cap and rotor for the distributor for the old original one, seems I may need to upgrade the whole thing. Trying to figure out the correct match up for that as well.

Wed Nov 04, 2020 3:58 pm

Ohio Tom said:

Quote: The oil bath represents a slight restriction in flow. Air actually has to bubble thru the oil (like a bong).

While its true that the oil bath air cleaner is more restrictive than paper....the "bubble through" thing is not quite correct.

and.....

Lingwendil said:

This is pretty much correct....but a little more to it.

Quote: It doesn't bubble through the oil. The fibers in the filter represent a restriction to the air and wick oil from the bath, allowing the particles to be captured. The sudden change in direction causes the particles to fall into the oil rather than follow the flow of air due to intertidal forces. But yes, there is a definite restrictive quality to them by their very nature.

This is spot on:

Quote: If it's bubbling through the oil you've way overfilled it.

The oil bath air cleaner actually works on centrifugal force just like a more modern vortex air cleaner seen on diesels and gas turbines. The oil is just a capture and collection device for the dust particles removed.

But....as VW used these air cleaners....they are actually a two stage system.

The air with dust enters the outer enclosure from the side. In may air cleaners it dips downward slightly to sweep across the vibrating oil pool...which MUST be filled only to the red line inside (most I have seen have a red line or an embossed line).

It picks up oil at this point and mixes with the air. It then has to make a hard...high speed...90* angle to go upward (I have seen filters on trucks that turn downward) into the "coir"...straw matrix (that is what teh straw like material in these is called).

That sharp 90* turn causes the heavier, larger particles to fall out. Thats the first stage of filtration.

That first dip to the oil pool from the inlet and this hard 90* turn is why you find piles of silt in the oil in those two locations in sandy areas.

As Lingwendil noted....as the air/oil/dust vapor winds its way through the "coir" fiber...its forced to make many rapid turns. The particles and most of the oil are too heavy to make these turns and are shed.

The oil that is shed....is important...because it brings the dust back down to the sump with it when it drains back.

I did a write up with some links and diagrams n this years ago. i will try to find them.
Ray

Wed Nov 04, 2020 4:02 pm

aderosier wrote: My bug is a 73', seems to run pretty smooth at this point, I'm only thinking about doing the tuneup because I have no idea when it was done last so it can't hurt. But something else I've noticed is they don't seem to sell the cap and rotor for the distributor for the old original one, seems I may need to upgrade the whole thing. Trying to figure out the correct match up for that as well.

What distributor are you talking about? Most Bosch distributors you'd likely find on a 70s Beetle will use the very common 03010 and 04033 cap and rotor.

Tue Nov 17, 2020 12:59 pm

ok guys, need advice on an oil bath air filter. I have a 73 super beetle, just acquired recently, doing a good clean up on the air filter. There is a thermocouple sensor of a sort going into the side of it with a spring loaded contact on the outside of the unit going to the aft end of the sensor. Shouldn't there be a wire or something going to this?

Thanks

Tue Nov 17, 2020 5:21 pm

aderosier wrote: There is a thermocouple sensor of a sort going into the side of it with a spring loaded contact on the outside of the unit going to the aft end of the sensor. Shouldn't there be a wire or something going to this?

Thanks

https://www.thesamba.com/vw/forum/viewtopic.php?t=581562&highlight=wax+thermostat