Collapsing oil filters

[Rob Frankham]

To me, the cause of a collapsing oil filter is much greater pressure on the outside of the oil filter, than on the inside.

I gotta agree with Jeff on this.

It only take 15 or 20lbs DIFFERENTAL acrose the filter to crush it on a later bike. This happens EVERY time you start it cold. That is why there is an oil filter presure relieve valve built into every oiling system out there.

I totally agree with that... however, to obtain that, you need to have both pressure relief valves blocked. The first one (under the front cover) to give excess pressure in the first place and the second one (in the filter housing) to prevent that pressure being released past the filter. The alternative is that the bearings are so loose that there is no effective back pressure in the system... but I think that would be pretty obvious from other sources.

Rob

[robtg]

To me, the cause of a collapsing oil filter is much greater pressure on the outside of the oil filter, than on the inside.

I gotta agree with Jeff on this.

It only take 15 or 20lbs DIFFERENTAL acrose the filter to crush it on a later bike. This happens EVERY time you start it cold. That is why there is an oil filter presure relieve valve built into every oiling system out there.

I totally agree with that... however, to obtain that, you need to have both pressure relief valves blocked. The first one (under the front cover) to give excess pressure in the first place and the second one (in the filter housing) to prevent that pressure being released past the filter. The alternative is that the bearings are so loose that there is no effective back pressure in the system... but I think that would be pretty obvious from other sources.

Rob

An open pressure relief valve will dump excessive pressure downstream of the filter causing more flow through it. Cold thick oil will cause more of a differential in pressure across the filter because of the increased flow.

[Major Softie]

I totally agree with that... however, to obtain that, you need to have both pressure relief valves blocked. The first one (under the front cover) to give excess pressure in the first place and the second one (in the filter housing) to prevent that pressure being released past the filter. The alternative is that the bearings are so loose that there is no effective back pressure in the system... but I think that would be pretty obvious from other sources.

Rob

An open pressure relief valve will dump excessive pressure downstream of the filter causing more flow through it. Cold thick oil will cause more of a differential in pressure across the filter because of the increased flow.

Correct. Rob is right and Rob is wrong.

An open excess pressure relief valve could crush filters, not a blocked one. An open pressure relief valve (or one that opens much too early) would create the same issue as "bearings . . . so loose that there is no effective back pressure in the system."

[Rob Frankham]

Yes. you're right... My bad. I was thinking the main valve is upstream of the filter not downstream... Ignore what I said in that regard... but on the other hand as you say, if the valve is stuck open you would get a bigger pressure differential. This means that if the valve sticks open, you not only get a crushed filter you also get oil starvation to the bearings... Either way, the problem is likely to be around the relief valves and it would be a VERY good idea to sort it out.

Rob

[barndeadr80]

I want to sort it out for sure. First thing will be checking the pressure as it is with a gauge. Gauge and adapter are on the way. As soon as I see what is doing both cold and hot I'll try and dig in there. I looked around a bit and did not see a good part # for the spring in the relief valve. Motobins sells the spring but there is no BMW # associated with it. If anybody knows the BMW # for the spring in the pressure relief valve I would love to know it. Seems like a new spring would be good to have on hand when all those parts come off.
Maybe it will all get sorted out and save somebody else a headache later.

[Deleted User 62]

I want to sort it out for sure. First thing will be checking the pressure as it is with a gauge. Gauge and adapter are on the way. As soon as I see what is doing both cold and hot I'll try and dig in there. I looked around a bit and did not see a good part # for the spring in the relief valve. Motobins sells the spring but there is no BMW # associated with it. If anybody knows the BMW # for the spring in the pressure relief valve I would love to know it. Seems like a new spring would be good to have on hand when all those parts come off.
Maybe it will all get sorted out and save somebody else a headache later.

Note: I think there are two DIFFERENT springs available. Do a search here on "pressure relief spring" , I think Me109 did a writeup on these. Edit: yep, two different lengths; 11mm= 11 11 1 250 159, 16mm= 11 11 1 337 576

[ME 109]

Note: I think there are two DIFFERENT springs available. Do a search here on "pressure relief spring" , I think Me109 did a writeup on these. Edit: yep, two different lengths; 11mm= 11 11 1 250 159, 16mm= 11 11 1 337 576

Wrong spring Tim. The springs you've mentioned above are for the oil filter bypass, which is located in the oil filter chamber.
There is an oil pressure relief valve attached to the front main bearing carrier, which also uses a ball and spring setup.
If the oil pressure relief valve is faulty due to the spring breaking, or the ball coming out, or the whole valve falling out of the bearing carrier, then a situation could exist where little pressure is able to build up on the down stream side of the oil filter.
That situation I believe is what is causing the filters to collapse, and could happen with normal oil pressure.

I've been/sent people on wild goose chases before!

[Major Softie]

That situation I believe is what is causing the filters to collapse, and could happen with normal oil pressure.

Yeah, I don't know if this IS what is causing the filters to collapse, but it COULD cause filters to collapse, and it would be very bad, but one should see the oil pressure light come on under those circumstances.

[Deleted User 62]

I've been/sent people on wild goose chases before!

Hmm, birds of a feather flock together? You're right, I lost the thead of logic at some point. I even saw that other spring on the fische, but because it wasn't on the same page as the oil filter....

[barndeadr80]

I get lost in this thing myself. Motobins lists a spring that fits all twins. I smack myself in the head and look at other apps and find the same plunger and hollow bolt and those list the spring. All the same # spring. A $1 spring. That would be just about right. All this for a $1 spring. The one in the pressure relief valve on the front of the engine.
Anyway, the engine has just under 50k miles on it. Since I am going in there anyway, should I expect to be replacing any chain tensioner parts? Be a good time to get them when I order the $1 spring.
The "other" spring and detent ball in the filter housing seem to be fine, and the retainer is staked in. Peened in.