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Re: Oil Pressure light on
Posted: Mon Mar 23, 2015 6:24 pm
by Kurt in S.A.
montmil wrote:BMW suggests an o-ring compression percentage of between 10% and 25%.
I never saw any numbers from BMW. These sound an awful like the numbers provided by Oak Okleshen in an Airmail magazine. Maybe Oak got them from BMW, but I don't think so.
Another take on the white o-ring "crush" is here:
http://www.largiader.com/tech/filters/canister.html
I see no reason to add a gasket for a canister this deep. To do so, only means having to add yet another shim. Gaskets are only needed if the canister depth is less than 3mm. Mine is 2.8mm...I have added the gasket.
Kurt in S.A.
Re: Oil Pressure light on
Posted: Tue Mar 24, 2015 10:44 am
by barryh
My take on Min - max O ring compression goes like this:
Min compression is up for some debate in terms of how much is needed to hold back the oil pressure.The figure I use is 0.4mm or 10%
Max compression is more easily cast in stone by whatever it takes to not extrude the O ring. In other words what are the dimensions of a a rectangle that just falls short of being filled by the O ring and that comes out at 4mm x 3.2mm so O.8mm compression or 20%
Re: Oil Pressure light on
Posted: Sat Mar 28, 2015 5:14 pm
by JJH
No joy!!! So I received my parts. Changed the oil and filter, including 3 shims and no paper gasket, bolts on filter cover snug. Filled with oil, cranked without starting to fill oil filter. Started up no oil light drove for ~4 miles and the oil light came on. Pushed and glided back home. Any ideas?
Re: Oil Pressure light on
Posted: Sat Mar 28, 2015 5:34 pm
by Bamboo812
I'd drop the pan and make sure the oil pickup hasn't gotten loose, and maybe install a new sending unit to be sure it wasn't at fault...
Re: Oil Pressure light on
Posted: Sat Mar 28, 2015 5:42 pm
by Kurt in S.A.
Maybe the pressure relief valve/spring/ball in the depths of the canister is always open??
Kurt in S.A.
Re: Oil Pressure light on
Posted: Sat Mar 28, 2015 7:44 pm
by Major Softie
Kurt in S.A. wrote:Maybe the pressure relief valve/spring/ball in the depths of the canister is always open??
Kurt in S.A.
That doesn't affect oil pressure. That valve bypasses the filter if it's too clogged, but when it is open it does not reduce the pressure delivered to the bearings. If it was always open it would just mean your oil wasn't being filtered.
Re: Oil Pressure light on
Posted: Sat Mar 28, 2015 9:09 pm
by Kurt in S.A.
Well, I was thinking that if it was open, it's a bigger "hole" letting oil back into the system as opposed to going through the filter. Even still, I suspect it wouldn't be enough to cause this I suppose...that light comes on with stupid low pressure as I recall.
Kurt in S.A.
Re: Oil Pressure light on
Posted: Sat Mar 28, 2015 10:50 pm
by ME 109
Buy a cheap oil pressure gauge and fit it where the oil pressure switch is. Should be 70-100+psi with revs.
Idle may be down to 20 or 30 psi iirc.
Big end bearings and crank main bearings are where the biggest leaks can come from. Could be the oil pick up as MS said, but it's not too common.
Re: Oil Pressure light on
Posted: Sun Mar 29, 2015 12:16 am
by Major Softie
That was Tim.
Re: Oil Pressure light on
Posted: Sun Mar 29, 2015 12:22 am
by ME 109
Major Softie wrote:That was Tim.
Sorry MS, I'm out of Boxerworks practice.
Sorry Tim, for thinking you were MS.
