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With all this checking ya balls and peening talk it reminds me of my youth in the shower

Thanks GSPD, Melville, George, Major Softie, for helping me on the path to enlightenment on the bypass spring.

My thoughts now.

The oil pressure in the filter cavity is X psi with a clean filter. The oil pressure in the gallery behind the filter cavity is also X.
The oil pump produces the oil flow and the oil pressure is (caused) governed by the pressure relief valve. ( and a tight motor)
If the oil pressure in the filter cavity and the gallery are the same, as governed by the pressure relief valve, (and a tight motor) only the pressure of the spring is holding the ball in place.
When/if the filter becomes blocked the bypass will open as the pressure drops in the gallery, thus maintaining equal pressure in the oil filter cavity and the oil gallery.

A clean oil filter, and indeed a reasonably dirty filter, must offer little resistance to oil flow, judging by the 'calculated' tension exerted by the spring.

Would it be fair to say that if the pressure relief valve failed or 'fell out' or the big ends and main bearings were 'really' crapped out, that the oil filter bypass would open because the gallery could not pressurise?

Easy on me know, I've got kangaroos in 'me top paddock remember!

ME 109 wrote:Thanks GSPD, Melville, George, Major Softie, for helping me on the path to enlightenment on the bypass spring.

My thoughts now.

The oil pressure in the filter cavity is X psi with a clean filter. The oil pressure in the gallery behind the filter cavity is also X. Not exactly. When there is flow through the filter there is always less pressure in the gallery than in the cannister.
The oil pump produces the oil flow and the oil pressure is (caused) governed by the pressure relief valve. ( and a tight motor)
If the oil pressure in the filter cavity and the gallery are the same It never is the same as long as there is flow., as governed by the pressure relief valve, (and a tight motor) only the pressure of the spring is holding the ball in place.What opens the ball valve is the "force" on the ball as opposed to the PSI on the ball. Since the gallery side of the ball has a much greater area of the ball exposed to the pressure in the gallery, a greater force is generated to hold the ball on the seat than the same of even slightly higher pressure in the cannister. The PSI in the cannister side of the ball is only exposed to the area defined by the hole in the retainer.
When/if the filter becomes blocked the bypass will open as the pressure drops in the gallery, thus maintaining equal pressure in the oil filter cavity and the oil gallery.

A clean oil filter, and indeed a reasonably dirty filter, must offer little resistance to oil flow, judging by the 'calculated' tension exerted by the spring.

Would it be fair to say that if the pressure relief valve failed or 'fell out' or the big ends and main bearings were 'really' crapped out, that the oil filter bypass would open because the gallery could not pressurise? Of course if the retainer falls out, the system is in permanent by-pass mode. Anything that causes the gallery pressure to drop low enough will open the valve.

Easy on me know, I've got kangaroos in 'me top paddock remember!

The red text does not represent shouting or any emotional reaction on my part, I just like red!

A simpler way of saying it would be:

The spring keeps all the oil going through the filter until it's harder to push oil through the filter than it is to push it past the spring.

I know it's simpler. Only you can say if it is clear.

Thanks again gents, I understand why/how the bypass is opened due to a blocked filter.
I was wanting to understand how the ball was held in place by the oil in the gallery (as well as the spring)
Also I wanted to know how a light spring was able to do the job.

I have a much better understanding now as to the forces applied to the ball.

It just passed the 600 km beat test with flying colors.
smooth as silk, just like before the knock.
I think I got lucky and will be able to get a few more odometer rollovers before needing a crank.
Time (and mileage) will tell.

Doing my first oil change on the new to me R60/6 and I'd like to poke around the relief spring etc.

I tried looking at motobins and using the two P/Ns listed for springs at motobins, but that yielded nothing.

I'd prefer a location in europe.

Regards, Lasse

Gidday Lasse, the parts are cheap enough to get from BMW. But find out if you need them first.

ME 109 wrote:Gidday Lasse, the parts are cheap enough to get from BMW. But find out if you need them first.

As I'm ordering other parts I might as well get these too. There aren't really any dealers around where I live so I am ordering from outside the country, not getting these 2 dollar parts would be unwise while at it

Well, they look like 2 dollar parts atleast

Lasse wrote:Well, they look like 2 dollar parts atleast

Well, being a BMW, if they're 2 dollar parts, they shouldn't cost more than $20.