Old Pictures of Oil Filter

[Air4Life]

I just located the following pictures of the oil filter that came out of the bike when I did the change, and decidedly went with the hinged type afterwards as per some guru's suggestions.  It also had the gasket in place, which based on some other guru's suggestion, this might have contributed to it being squished.

I was surprised how much the inner tube got crushed.  Do you think this had the oil,  bypassing  the filter?  The pleats were separated and show'd no signs of metal.  I guess its good if oil was passing through it...

[Bob_Roller]

If the filter restricted oil flow enough, there is a spring loaded bypass valve in the filter cavity, it's the small silver ball in a socket at the far end of the cavity .

Our site administrator, Justin B, put an oil pressure indicator on his R100 a few years ago .

The oil pressures he got were quite high, if I'm not mistaken, at around 85 F. 'cold' start pressures were in the 100 psi range, revving the engine up at the temp sent the oil pressure to 130 psi .

Imagine what the pressure would be in cold temperatures that were still in the rideable range .

The picture of the filter that you posted, is it an OEM filter, or aftermarket ?

[Air4Life]

Thanks Bob.  

To me  it appeared to have been an aftermarket one.  It was in the bike when I got it.  I have to check the documentation that was passed on to me from the previous owner.  I know he had billing for lots of stuff, and I'm pretty sure the filter was noted.  Maybe they jotted down  part numbers as well.

[Barry]

Welcome to the flat twin filter club. Although not common this has happened to many people over the last 30 odd years.

http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1269110468/5#11

It's a bit of a shock but as Bob said the bypass valve will open so the engine does not get starved of oil although it will be unfiltered oil. To put it in perspective though the bypass valve probably opens every time you start a cold engine especially in the winter.  My flat filter occurred over 2 years ago and there have been no long term consequences that I'm aware of. It did not happen to me again as I am now very careful not to use too many revs at freezing temperatures.  The 2 part bendy filter will be stronger and it will improve your odds substantially but this has also happened to bendy filters in a few cases including BMW supplied filters. The earliest documented cases I found occurred in the early 80's when aftermarket filters were probably unavailable. BMW was forced to change it's filter supplier at the time.

[wa1udg]

Perhaps a good justification for synthetic oil.  

[Julio A.]

I wonder what causes this kind of problem. Could it be an inferior filter or incorrect shims?

[Bob_Roller]

The high oil pressuer on start, it exceeds 100 psi, in cold temps, it can approach 150 psi .

Usually it is an after market filter that collapses, must be materials and quality of build .

[Air4Life]

It was an aftermarket filter that he had in it.  Its true, I did ride some throughout the winter (mild this year); where I started it a dozen times or so with temps in the mid 40's F.  So its possible that may have contributed to the collapse.  

I measured its depth and its one of the deeper ones.  I removed the gasket as per instructions, almost deep enough to require another shim.  I have been running the split type as per gurus here and about, and so far no problems.

[nhmaf]

Yes, some brands of filters, particularly of the single, straight canister type and not the 'bendy' ones that are like (2) little cannisters end-to-end, are more prone to this type of collapse.  I think that "Fram" may be one of those brands.   For this reason, many folks always get the bendy type of filters, which, due to their shorter tube lengths and 2X as many end caps, are more resistant to crushing.    The oil pump system on these bikes does generate very high oil pressure, especially when the oil is cold, which can cause this to occur upon startup.   Other things to mitigate/avoid this problem:
1) Don't start the cold engine and immediately start revving it - let it simply fast idle below 2000 rpm for a bit to start to warm up.
2)  Some folks insist on running very heavy, thick oil (20W50) in these bikes.   I see absolutely no reason for this unless one is living in very hot climates like our friends in Texas, or Arizona where the summer temperatures are very frequently above 100F/39C.  I run 10W40 in mine for the 8-10 months per year that I ride, and it does fine for the few days per year where the temperature may hit 100F around here, or if I make a couple day trip down south.   It also allows the engine to turn over fast enough to start reliably when I still want to ride in late fall or early spring when the temps are near 0C/32F.

[Barry]

Agree with nhmaf on using thinner oil in a temperate climate. I have been using 15W40 for years now and have no intention of ever using 20W50 again. Try pouring 20W50 out of a can at 0 deg C and  imagine it being pumped around the engine's tiny oil ways at a snails pace.  The automotive indiustry has moved on from 20W50 and although much of the reason is closer engine tolerances I believe it is also a change in philosophy from worrying about oil being too thin when it's hot to worrying that it's too thick when it's cold. And they do say most wear takes place when the oil is cold.

Fully understand using 20W50 in the hotter climates though.

[Air4Life]

Gosh, with what you've  described here, I would think one would expect to hear some cantankerous sounds on those type of starts; or is it that the by-pass pops quickly enough to allow oil to get to its proper destination before any noticeable sounds are generated?  

If the above is the case, than that might suggest that the Oil filter causes the greatest impediment to flow; and a manual bypass would be ideal for cold starts, or for the more realistic, a preheat of sorts.  

I spend far greater hours operating at 5500 rpm than I do starting in the mid 40's F.

[Barry]

I don't think the bypass valve makes a noise at least it's not audible with the engine running. I also believe it opens not just when the filter is blocked or flattenened but at every cold start. The maximum oil pressure is supposed to be 74 PSI but even with the bypass open this pressure will be greatly exceeded as has been demonstrated by measurement.  This extract from a description of the lubrication system gives some idea of how powerful the oil pump is.

"At 3400 rpm the oil pump is delivering freshly filtered oil to the bearings at a rate of about 212 gallons per hour. Which means the entire oil supply of the engine is recirculated about six times every minute or once every ten seconds."

Those flow rates are with hot oil at 74 PSI. With cold oil the flow will be much lower but at a much higher pressure.

You'll probably laugh at this but another reason for not wanting excessively thick oil is that the oil pump consumes horse power. It must do and more power when cold than hot. On the racing BMW's I believe it became such an issue at high revs that they had to do something to reduce the pumps output as it was reducing the engines maximum power by a significant amount.

[Air4Life]

Neat, thanks for that information Barry.  

One clarification:  I was not referring to the bypass making noise itself, but rather the under lubricated areas of the engine becoming noisy as a result of the suggested starved cold start symptoms.

[Barry]

OK I see what you mean. I've certainly had engines with a bit of top end rattle until the oil got circulated all the way through the system to the valves.  And that time delay is a good reason not to have oil that's too thick. That's why Honda even in the seventies made a big deal about using nothing thicker than 10W40

Can't say I've noticed the problem with airheads though.