Volvo RWD 444-544 Forum

There have been several postings in the past from people who have modified their SU air cleaners using different replaceable air filter elements. So this is not a new idea - just another filter element source. I came across a replacement for Kohler Air Filter #4508302 at Lowes: 6" diameter, 3" thick. The nice thing about this filter is that it comes with a washable, foam pre-filter sleeve, which is originally gray, but which I painted red, for eye-appeal, with some Plasti-Kote Vinyl Color I still had on hand. The pre-filter gets a few drops of oil to help it filter out more dust. The procedure is to liberate the two cover plates of the SU air cleaners and to sandwich the filter element beween them, after trimming the rubber end-seals a little bit and making up some 3" long spacer tubes that the bolts go through to hold the gadgets to the carbs. I did this with two-hole filters, but the effort is really more worthwhile if you need to replace your three-holers, which are harder to come by and more expensive.

Bob S.

Here's a few cross-reference part numbers for these air filters and foam pre-filters.

KOHLER PART # 45-083-02 / 45-083-02S

CUB CADET PART # 61606-C1 / 759-3359

GRAVELY PART # 034766 / 046344

JOHN DEERE PART # AM 37201 / AM 31034

ONAN PART # 140-1216

MASSEY PART # 1044627MI


Still happy with them, Robert?

--Aiden
Boulder, CO
1957 PV444L
1966 220 (For Sale!)

Thanks, Aiden, for that information. It's going into my file. Yup, I'm still happy with the filters. I keep imagining the car runs a little better, although I had no reason to complain about perforance before, but haven't any concrete evidence that this is so. If there is any improvement in mpg, it gets obscured by the normal variation in mileage from one tankfull to the next that results from the mix of in-town and open-road driving that I do. Next time I fiddle with the carbs, however, I'm going to go Barongrey's route with the threaded rods, but still using the spacer tubes. That should make changibg filters a lot easier. The stiffer my finger joints get with age, the more I'm dropping the filter bolt nuts, and God only knows where they end up, 'cause I never find them back.
Bob S.

Bob .... at "Our" advanced age haven't you discovered that things like dropped air filter bolts and nuts are sucked into a vortex of time and space and they will only return when the stars and planets are in the correct configuration ? ;-)


Brett
--
Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com

If I could take my car and turn it upside down and shake it good, I'd get a bushel of bolts, nuts, and screws!

The worst ones so far have been the filter nuts that go behind the carbs. I think I went through 20 stainless self-locking nuts before I got 4 sets to stay on!

I, too, clipped the filter parts numbers for my file. Now to find the parts....

Steve

No! NEVER!

What are you suggesting? Making the job easier???? ;-D

Yes, the next time I have the carbs off the engine and the right size tap handy, I'd certainly try that...remembering that the soft aluminum threads will get all chewed up the very first time I try putting a bolt into them! (My wife calls me Dr. Destructo because so much goes wrong when I try to fix things...)

Seriously, threading the air filter holes is a very good solution, even better if you can find a steel thread insert that will protect the soft threads of the aluminum carb bases.

I think I've found an even better solution in that big box of old SU carbs and intake manifolds my Dad put in my truck; there's one set of carbs with backing plates and straps that allow the use of a cover with one center bolt instead of the two bolts we're using now. I've seen SU's with one-bolt covers, but so far I haven't seen inside them to see how they are set up.

I'll need to slean these backing plates up and paint them, then find a right-size set of covers (chromed?) and filters for them.

I was in a rush when I saw the carbs, and it's still a little cold for me to go outside yet this morning, but I'm thinking that the backing plates are the standard size.

On a slightly different note, I'd sure like to find a set of those dashpot top plugs in aluminum instead of the black plastic. After all the work I've done polishing out my carbs, those would be the cerry on the ice cream!

Barring that, I'll probably paint the plugs to match the car.

Steve

You know, Steve, I have a set of spare three bolt-hole SUs that came off a B20B, and on those the filter bolts just screw into the carb flange; and on the two holers I have on the car it looks like there are vestigial threads left in the holes - as if the threads have been reamed out. Maybe these things originally all came with threads, although that seems unlikely because I think I remember fiddling with those filter nuts all my Volvo-owning life - going back to the washable bronze-wool filters that came on the early B16s. But then, my memory is going the same route as my finger dexterity.;-(
Bob S.
PS: I remember now, those early, washable B16 filters had the thread in the filter, and you had to worm the bolt (a short one) in from the back. Oh, man, those things were really miserable!

Sil;

Maybe those "vestigial threads" were just what was left when someone wanged some oversized bolts in there (God knows what filters he used, or how they looked afterwards...)... having the right idea but a neaderthal implementation...

Helicoils work great, but I expect so would PEM inserts (that's what I've used with very satisfactory result)...should I make up some upgrade kits?

Cheers

Let's see...a tap (I'm pretty sure most of us don't own a full set of taps and dies) and set of four (or six) helicoils with insert tool...

That wouldn't be too hard to put together, and if the pricing were at about $15 they would probably go like hotcakes.

I'd stay with my current threaded rods with wing nuts on the top, but inserts would sure make the initial installation a lot easier! Write me up for a set before I head for the hardware store!

Steve

Ron,
Others may well be interested in an upgrade kit. I would not be a candidate at the moment because I just rerigged mine with threaded rods that I don't need to remove anymore. Just take off the front cover and replace the filter element. Thanks for the thought, though.
Bob S.

Nice work Bob. Question, underneath the foam cover is it a pleated paper filter element? And...what is the original application for the Kohler filter, snowmobile,chainsaw,lawnmower? Just curious what the engine size it was intended for.

Thanks, Jim

Jim,
I don't know precisely what those filters are for, but I assume they are for MTD yard equipment that have Kohler engines (Cub Cadet riding mowers?). Obviously they are intended for a much smaller engine then the B20, but I don't notice any air flow restriction, on the contrary. But gas mileage will tell, and I'll report on that in this thread after I've run a tank-full through them. So, check back here in a couple of days. The paper part of the element appears to be a little thinner than on the regular SU filters. There is wire mesh on the inside, and outside of the paper element to support the foam cover. This mesh is much more open than what the original Volvo part #73606 had only on the outside. Most of the after-market filters you see today have no wire mesh on them at all. BTW, I Googled Kohler #4508302 and several vendors came up with prices about half of the +/- $12 a piece Lowes charges, but then there is always the shipping cost. Not all of the internet vendors show the foam cover, which may, or may not, mean something.
Bob S.

185 Miles of rural roads plus small town driving, at least, showed no increase in fuel consumption. There may have been a small improvement that could be attributed to the Kohler filter elements, but it was not noticeable enough to brag about. A bit more highway driving may show more conclusive results. Nevertheless, I still feel that the car runs better.
Bob S.

Hey Bob ... How come you didn't point those out to me while I was down visiting ?? Neat Guy !!!

Brett
--
Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com

Hey Bob ... How come you didn't point those out to me while I was down visiting ?? Neat Guy !!!

Brett
--
Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com

Brett,
I wasn't holding out on you. Made them up this last weekend because I was still smarting over those super nice the Australian air cleaners you snatched up from under my nose ;-). Anyway, I just took them for a drive, and the engine definitely revs up faster. I guess a B20 with a carbed F head needs more air than the smaller filters that came originally from the B18 would let through. It could, of course, just be my imagination - I always feel the car runs better also after I washed it or changed the oil.
Bob S.

OH ... So NOW you come out with all these sofisticated performance tricks .... ;-)I'm sure that the amount of weight you lose on that old 544 must be quite considerable after it has been washed ... sure to help performance ;-) BTW I didn't tell you, when I wind Ole Reliable up with these neat new Aussie/Weiand Foam filters... I get a very TURBO like whistle .... which I am sure is good for at least 50 or so HP ;-) SEE what you missed out on by not being quite as swift as I under the hood of that 220 wagon ??

Give Rosita a hug from me ...

Brett
--
Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com

Not to laugh, please!

Washing the car removes surface grime that disturbs the airflow, resulting in a higher top speed. Of course, this only applies if your car exceeds Mach 1!

Yes, I always feel the same; an hour or two communing with my PV and giving it come quality time always seems to make it run better!

As far as the air filters go, thanks for the tip. I, too, gutted my nasty old stock filters and I'm always on the lookout for inserts that will improve the airflow.

I set up my 'cover hold downs' a little differently, though.

I bought some stainless steel all-thread rod and cut some lengths to fit the new, higher location of the top cover. I threaded on a nut, leaving about 1/2" inch of rod sticking out, which I ran through the bottom cover plate then through the carb hole, and backed it up with a locknut and another nut.

In effect, this gives me two 'studs' that stick up from the carbs, holding the back cover in place.

Next, I threaded another nut onto each rod, leaving - again - approximately 1/2 inch of rod sticking out on the top end. I then put in the filter elements, set the top covers on, and topped it all off with two stainless wing nuts.

In order to get all the wing nuts aligned when they are tight, I had to fiddle with the top 'stopper' nuts, running them up or down a fraction of a turn until I found the right spot where that wing nuts will all point the same direction when they are tight.

I can see the simplicity of your plan, though. Cutting some tubing to length and using a bolt instead of all-thread would be much simpler.

I think the advantage to my setup is that once it's in place, I can just remove the wing nuts, top cover, and filter without having to struggle with a nut on the back side of the carb. Besides, I like the way those stainless wing nuts look. ;-)

Another tip: If you come across a good deal on 3-hole filters but your carbs have only two holes, dig through the 'HELP!' section of your auto parts store and get some black plastic headliner push-ins. They look like a giant thumbtack. By trimming just a tiny bit off the barbed rod, they will press right into the unused holes in your filters, and they look like a stock item.

NOTE:

I've tried a FRAM filter, and although I had to cut it in half (one filter makes two Volvo filters) it works great. Not the easiest thing to do though; you'd be surprised how difficult it can be to neatly cut a filter down without making a mess of it. I like these, though, and I use them for everyday driving out here in the dusty desert. At under $4, they're hard to beat!

I also came across some lawn mower filters that are about 2" tall, and the right diameter. Don't bother trying those; they're too restrictive. My gas mileage dropped to about 25 mpg (from a usual 30 mpg.)

I'm going to need to go to Home Depot today, ao I'll look in the small engine section to see if they have the Kohler filters...They sound like they'd be just right.

Steve