K&N Air Filters for Webers - What do I have?

patssle · 07-13-2011, 08:05 PM

These came with my carbs that I picked up at a garage sale. Carbs are rebuilt and on the engine. Now time to deal with these. Are there different types of filter setups for carbs? It seems I have 2 different types?

I have all the nuts and bolts hardware for A, but am missing a bottom plate. However the filters won't squeeze into the A set. Are there different sizes?

Do B and C go together? What's their story?

JerryL · 07-13-2011, 08:19 PM

I had a set like that. The "A" parts look correct, the filter elements do not look to be the correct K&N (or even K&N?)
Is the plate on the bottom of C the same size as the A carb plate?? maybe you could drill holes to match the Aluminum K&N top plates.
Most are mounted with pcs of all thread about #10 or 4 - 5 mm and nylock nuts.
B is a stock airfilter base.
As you know not quite a set of anything BUT close, K&N has 2 or 3 different filter element heights that fit the plates, look around on the net or pelican for the weber filter elements

Regards

patssle · 07-14-2011, 07:10 AM

Great info, thanks! Looks like A will be my best bet if I can find another bottom plate (after I try C) and appropriate filters.

If there are 2 or 3 different types, how do I know which one is appropriate for A? Or is it just height that is different, and any will fit over the air intakes?

1QuickS · 11:04 AM

C's were early version used with Filtron's; the steel "boats" with over-center spring clips are the bottom portion of OEM air filter assy and A's are cast aluminum and much stiffer than C's so are a better for filters to seal against.

patssle · 07-14-2011, 08:15 AM

OEM, hmm maybe they are worth selling?

Are the cast aluminums (A) any similar to the K&N Watershield kits that are currently for sale (Pelican, PMO) or are they different? Will the Watershield filters fit in these?

stownsen914 · 08:50 AM

Patssle,

I went through something similar last year. You've got several different kinds of air cleaner housings there. It looks like the ones labeled A in your picture are the PMO non-rainhat style. (Edit -- Actually I see that the housing tops are secured to the bases with springs, which would not be PMO. Not sure what brand they are.) I see the K&N aluminum style ones on the right side of your picture. Though similar in style, the PMO and K&N ones are slightly differently sizes and from what I could tell, use a slightly different diameter filter element. I found that the K&N filters for the PMO housings were a little bigger than the filters for the K&N housings. (Edit -- even if the A ones aren't PMO, they might use different size filter elements than the K&N housings.)

The housings labeled B look like the bases for a stock air filter housing, which is completely different from the K&N style housings.

Scott

911pcars · 07-14-2011, 09:41 AM

The filter housings labeled "C" are units made by Filtron for their foam filters (NLA). The K&N "Watershield" type filters that are designed for filter housing "A" should also fit inside them. As you see, the filter is sandwiched between top and bottom by a number of tension springs. BTW, they are the lightest of the ones shown.

Sherwood

snbush67 · snbush67's Garage

The bolt spacing for the "A" bases and the K&N top are different then the Bolt Spacing on the PMO water shields.

I modified my PMO bases to change the bolt locations so I could use the K&N tops with my PMO 46's.

The "A" bases would not fit on my 46 PMO Carbs. They probably would have fit on 40's. So I have a set of "A" bases if you need them. I am going to hang on to the water shields.

patssle · 07-14-2011, 11:30 AM

Hmm, so you fit Watershield filters into your original K&N tops (my A in original picture)? Others say they won't fit.

Do you mind measuring the holes for the velocity stacks, what are your size? Maybe a photo if you can? I'll be interested if I can verify specifically what filter will fit into my K&N top/bottoms.

snbush67 · snbush67's Garage

My filters are the K&N that came new with my PMO 46 water-shield set up. I used the same bases and filters, I have just substituted the K&N tops after modifying the bolt spacing of the bases to match.

The holes for my velocity stacks are larger then those shown in "A" that is why I had to modify and use the bases that came with my set up. If the filters you have are K&N they should form to the K&N tops.

Try putting the filter in between the base and the top the filter should form to the outer edges of the top and base. If the filters dont work in one set, then they probably wont work in any and are meant for a different application.

KTL · 07-14-2011, 01:40 PM

Note that "Watershield" is not a brand. It's a type of lid for the carb filters. It's basically like a hat or lamp shade over the filters to reduce the likelihood of the filters sucking in water

patssle · 07-14-2011, 01:42 PM

Hmm, if your holes are bigger, that might not work for me? I'll have to look at it when I get home.

Looking at pics it seems K&N filters are not black, so mine must be something else. I'll look closely for markings. But they will not fit into A.

KTL: What is under the watershield lid? Is there another lid like in my A photo, or does the watershield provide as the top piece?

KTL · 07-14-2011, 01:49 PM

Nothing under the watershield lid. It's just like a flat lid, but has deep, flared sides to shroud the filter media a bit from water suckage and still provide a suitable airway to allow good airflow thru the filters

patssle · 05:09 PM

Well, apparently those filters ARE K&N. But here's my problem, they are too big. I tried fitting them into the C filter-holders. I assume filters that are suppose to go with them easily fit, no need to bend them like this? Same thing happens when I put them in A.

BTW if anybody wants to buy B as it's mentioned they are OEM, I'll sell those.

911pcars · 07-14-2011, 05:10 PM

Quote:

Originally Posted by patssle

Well, apparently those filters ARE K&N. But here's my problem, they are too big. I tried fitting them into the C filter-holders. I assume filters that are suppose to go with them easily fit, no need to bend them like this? Same thing happens when I put them in A.

Compare the base plates for A and C. They should be identical. While they are different brands, the K&N-specific filter should fit both. Are you sure those are K&N branded filters for a twin filter 911?

Sherwood

patssle · 05:25 PM

Quote:

Originally Posted by 911pcars

Compare the base plates for A and C. They should be identical. While they are different brands, the K&N-specific filter should fit both. Are you sure those are K&N branded filters for a twin filter 911?

Sherwood

A plates are slightly larger, just a couple millimeters. No I don't know those filters are for the 911, they just came in the box with the mix of filter plates.

But I just had an epiphany! I have a complete plate pairing of each type, I can put one A and one C on the engine for now until I find parts.

I guess the only thing I want to know is that it's guaranteed the K&N Watershield Filters (as sold by Pelican) will fit into both?

911pcars · 07-15-2011, 01:31 AM

Quote:

Originally Posted by patssle

A plates are slightly larger, just a couple millimeters. No I don't know those filters are for the 911, they just came in the box with the mix of filter plates.

But I just had an epiphany! I have a complete plate pairing of each type, I can put one A and one C on the engine for now until I find parts.

I guess the only thing I want to know is that it's guaranteed the K&N Watershield Filters (as sold by Pelican) will fit into both?

You could perform some math. Measure the perimeter of the mounting area on the base plate, then calculate the OD (diameter) of the filter (round circle). Compare with a replacement K&N. Or do the same with a piece of string, then form into a circle and measure the diameter.

I have searched for an off-the-shelf throwaway pleated paper filter to use instead of the oiled pleated cotton type, but K&N sizes this particular one so they manufacture the only filter that fits their housing. However, last time I researched this was about 5 years ago. Go to your local aps and peruse their air filter master catalog for equivalent height and OD. Could be different now.

Sherwood

patssle · 07:54 AM

Quote:

Originally Posted by 911pcars

You could perform some math. Measure the perimeter of the mounting area on the base plate, then calculate the OD (diameter) of the filter (round circle). Compare with a replacement K&N. Or do the same with a piece of string, then form into a circle and measure the diameter.

I would love to do that, if I had access to a filter! Not sure of anybody locally that sells the one for our cars specifically. I can't even find them on K&N's website, and I searched by dimensions (in a range) and by car.

If anybody has one and wants to wrap a piece of string around it - that would be much appreciated! I'll see if if the APS has a catalog, but I suspect it'll be like K&N's website.

911pcars · 07-15-2011, 11:19 AM

Quote:

Originally Posted by patssle

I would love to do that, if I had access to a filter! Not sure of anybody locally that sells the one for our cars specifically. I can't even find them on K&N's website, and I searched by dimensions (in a range) and by car.

If anybody has one and wants to wrap a piece of string around it - that would be much appreciated! I'll see if if the APS has a catalog, but I suspect it'll be like K&N's website.

Not the filter (read post again). Measure the base plate surface, the lip that contacts the outer surface of the filter.

BTW, what's the OD of the filters you have? Form into a circle, then measure.

Sherwood

stownsen914 · 07-15-2011, 02:36 PM

I have some PMO housings and also another brand (not sure of brand), and they are somewhat different sizes. I don't recall the measurements offhand, but I remember that the PMO ones were something like .5" wider and about the same length. This is probably why the PMO K&N filter elements don't cleanly fit into the other housings.

Scott