OIL FILTERS

[Mike V]

James,

There "is" a reason for the metal shim. On early models the canister has a sharp edge and the shim helps protect the o-ring from getting cut or damaged from the canister lip. It also helps distribute even force on the o-ring. It's not manditory. I know of a lot of airheads not using them. The main goal here is to make sure the o-ring has adequate compression and sealing properties. Don't mean to push this thread to exhaustion, you've received some pretty helpful information, lots of very good knowledge and experience on this forum. Good to know your o-ring appears it's been doing the job. Here's a link to clarify the sequence of installation for the metal shim (#6). I wanted to attach this to be sure the installation sequence was clear.  Personally; I think canister depth measurement should be SOP for this exercise. Just my opinion, doesn't make it right and once it's done and recorded it results in correct compression...and piece of mind. Sorry to deflect any attention regarding the filter collapse - but it's (possibly) all related and the process of elimination is important. OEM filter, canister depth measurement, o-ring & shim installation, start-up procedure, oil viscosity, by-pass valve.

http://www.realoem.com/bmw/showparts.do?model=0364&mospid=51897&btnr=11_1721&hg=11&fg=35

Monte, you out there?

[Bob_Roller]

If you are wondering about item number 7, o-rings, the earlier version of this filter didn't have any seals incorporated into the filter body, there were o-rings on the tube in the engine, and one on the filter cover .

[Mike V]

Great point Bob - thanks for the clarification, the fiche shows the outdated filters with filter rings.

Gone riding...

[montmil]

Monte, you out there?

Yep. And enjoying every minute reading of the education of a new airhead rider. Is that a double entendre?

I'm [smiley=thumbup.gif] with you Mike, Barry, Bob, Rob and NH Mike. Y'all all correct.

Monte

[bjamesw]

Would someone please illustrate this with photos?
I posted a few over at advrider
http://www.advrider.com/forums/showthread.php?t=617367

Does the oring need to seal the edge of that barrel that surrounds the filter?   If not, then all makes good sense and I'm fine.

Were the old style filters that much larger?  The present filter does not come anywhere near contacting the oring.   The shim was originally introduced to protect the oring from the filter's sharp edge?

[donbmw]

The Picture on advrider showing the filter cover is the right way but the shim is on upside down. The shim has a curve to it that goes next to the oring.

[Bob_Roller]

The o-ring seals the filter cover, the paper gasket isn't up to the job, the three bolts that hold the filter cover on strip out the threads in the aluminum case quite readily, so can't tighten up the three bolts to do any real good .

If you cut the o-ring during reassembly, the oil comes out from under the filter cover after you start the engine .

[Rob Valdez 79 R65]

I cut an o-ring about 6 years ago.  I don't know how, but I know that when I got to the gas station a few blocks from my home, I almost fell when I put my right foot down and there was oil on the ground!

Be sure and check for leaks the first time starting after a filter change.  Maybe look at it once a week while the bike is warming up.

And most of the fasteners on these bikes are tapping into aluminum castings, so the aluminum threads are going to strip if you try to tighten things to get oil to quit coming out.
I have personally stripped a driveshaft drain plug in attempt to stop a drip.  In my defense, that was in my early years, back when every dealer was an airhead-friendly dealer! lol!  (They performed the installation of a helicoil.)

[Barry]

bjamesw,

Nice photo's on Avrider.

For clarity Anton Largiaders section drawings make it all crystal clear
other than he shows an oil cooler type installation. This makes no difference to the location of the O ring and shim.

http://www.largiader.com/tech/filters/canister.html

[montmil]

I have been using the WIX "bendy" filters for quite some time. Far easier to install than the one-piece filter.

The WIX product is well respected among the Airhead cognoscenti. The attached link is my vendor in Colorado. Buy a package of two or more and the shipping is free. Fair pricing.

http://stores.ebay.com/filtercycle/_i.html?_nkw=BMW&submit=Search&_sid=20143097

[Justin B.]

If you want to stay OEM (while saving a few bux)  then order the corresponding Mahle filters as they make them for BMW...

[bjamesw]

The oring measures 4mm.  The shim measures .3mm.   This is true for the OEM and it was precisely true for the parts I just installed from NAPA.  

I just instigated a little tiff over at advrider for posting an image and graph taken as captures from articles on the net that adress this whole airhead filter question.  Well, my posting was called "crap" anyway, if that rates a tiff.  

I was trying to offer some ABC for anyone stymied by the sheer embarassment of richness in detail afforded to this topic.   The article suggested arriving at something close to 3.3mm as an ideal offset for the 4mm oring to squish into.  And the image offered no doubt as to the placement of the shim.  3.3 can be arrived at by whatever combination of shims and gaskets you prefer.  Sounded fine to me.  Puts it at a little shy of 25percent squish rate for the ring.

I failed to notice that the original author of the content was in fact a thread participant so he, naturally, took offence to the plagarism. 3.3mm was a hunch, and apparantly nothing that he felt he personally should be held fast to (I'd left that disclaimer out of my reprinting).  Fair enough.  Honestly!   So that still begs the question...

...if not 3.3mm...  what should we aim for?  

[nhmaf]

The ~25% "squeeze" of the white O-ring is the generally accepted amount by many airhead gurus, most of which are too busy/wise to bother with the ADV rider forum, (except for Anton L) but in any case, that should be the goal for anyone with an airhead to service.    Going to more than 50% or more squeeze is much more likely to result in a slipped or cut O-ring, so while there is some practical upper limit, it is still a rule of thumb.   Too little compression of the O-ring can result in incomplete sealing, which causes loss of oil pressure which in turn, can be fatal to the engine, so most everyone goes for the middle of the "squish range" that will most likely ensure good tight sealing, generally avoid cutting or slippage of the O-ring, and not require so much torque as to pull threads out of the engine casing when turning the oil cover bolts snug.   Bob Fleischer (snowbum), Paul Glaves, and many other well published airhead experts all follow/proclaim these practices, and we the faithful learn and follow their lead.   They know far more about these bikes than most of us will ever know.

What further confuses things is that BMW had (2) somewhat similar, but different designs during the period of /5 models in 1970 through 1995, and, there are some significant "variances" in the tolerance of the dreaded "oil canister" of either design.  This results in people doing things in various ways for various reasons - only some of which are based in logic.   The key thing for you to remember is to determine the proper stack up for your particular airhead, and then be consistent with following that method to achieve to proper amount of O-ring sealing.   In the vast majority of airheads using the canister design of your bike, they need the metal shim, though in at least some cases, it might be possible to do without it.   With the situation in my bike, I know that if I didn't use the metal shim, I'd likely end up with a slipped/cut O-ring and problems with sealing.

[Barry]

nhmaf

I might of missed something but Just to clarify when you mentioned 25% and 50 % squeeze did you mean 0.25mm and 0.5mm compression ?

If we are talking about 25% squeeze of the O ring diameter then 25% of 4.00mm is 1.00 mm compression. I think that's just a little too much and may extrude the O ring past being square. I don't go beyond 0.8mm compression. (at least not since I had a crushed oil filter).

I guess what I'm saying is 25% (or 1mm)  compression may just be acceptable but it is the absolute upper limit and not the target to aim for. The reasoning is a 4mm O ring will fill a 4mm X 4mm slot at approx. 21.5% compression. That's why I set the upper limit in my table a little lower at 0.8 mm.

There is another issue to consider.  When I measured the canister depth I found it was not even all the way around and I suspect others will be the same so unless you are very careful to average the depth readings it can be another reason to use a little less than the maximum compression or risk extruding the O ring past square.

[nhmaf]

Hi Barry,

I meant ~ 25%, so ~ 1mm, as a very general/rough target - actually anything above 15% and below 25% is probably fine.  O-rings squeezed to an amount approaching 50% often show evidence of twisting, cutting or other things which can compromise the seal and should be avoided.

Many folks will say that as long as the O-ring has a somewhat more "squared" looking appeaprance when removed for periodic oil/filter changes indicate that the amount of compression is good.  Not mashed flat, not squashed to the point where it is only 2mm thick, but still recognizable as once being round in cross section.

So, in my book anyway, 18% is good, 20% is good, even 25% can be good, but 50% or 5%...nope. 25% as an upper limit is fine, but I think that if someone's number come out to be 28% or 30% will the engine explode - I don't believe so - but I agree that going above 25% increases chances of O ring damage.

You bring up a good point about the canister depths not always being consistent all the way 'round.   The canister is just a sheet metal stamping that is inserted in the engine case cavity, and it is entirely possible that there is some variation.   Many guys I know typically measure the depth around the canister at several places, and as long as one reading isn't grossly different from the others use the average for determining paper shim, etc. usage to adjust for proper compression.