Oil filter depth gap: The $2000 O-ring.

[datchew]

I'd like to continue with new info on that but cannot find the old thread.
Please advise if you have it. Otherwise, i'll continue this new one.


If you haven't seen Matt Parkhouse's article (Matt's in the hospital right now by the way so if you're the praying type... you know what to do.) in the BMOMOA March 08, or if you haven't seen the other thread, here's a quick summary.

If you take off your oilcooler cover plate, and measure the gap from the face of the filter to the flat machined surface of the engine case, it should be 3mm. Pics in magazine, and my own to follow. Maybe tomorrow i'll upload them.

Matt states that your white O-ring should be squished to look kind of square in its cross section after service if it was installed right.

You are supposed to use the metal ring shims to adjust closure of this gap to 3mm.


NEW DRAMA:

My gap during an oil change today (measuring the old filter) was 5mm approx.
No need for panic. She's running fine. Time to shim.

I put in the new filter and the gap was different! It was 4.3mm. So I pulled out both old and new filters and a vernier caliper and measured length of each entire unit (squeezing together to seat hinge in the middle).

Then I measured each can segment (metal end to metal end) separately and guess what. Same part #. Same "made in austria" but they were off by approximately 0.6mm. That's what I call a manufacturing process out of spec.


So, word to the wise. Get a vernier caliper and measure each oil filter.

I ended up putting 3 shims in with the new filter which brought my gap down to 3.4Xmm and made it so that without the aid of the screws, I could not just push on the cover to make it compress enough to lie flat against the engine case. So, I feel like i'm safe with the 3.4mm.


Now, I measured 5 shims (that's all I had) and all of them measured exactly 0.28mm, so i'm guessing it's safe to state that this is the correct shim thickness.

[AliBaba]

I wouldn’t recommend using more then one shim; solve the problem not the symptoms…..

Why do you measure the length of the filter?
The filter has big o-rings in both ends; it has to be a lot out of spec (several mm) to make any problems. It’s the canister depth that counts.

Puking oil: http://www.advrider.com/forums/showthread.php?t=211923
Shimming oil filters: http://www.advrider.com/forums/showt...=286618&page=1

[beemer67]

I agree with the above writer, that length of the oil filter is really not of any interest. It has no bearing on anything. But, adding multiple shims IS solving the problem caused by the symptom of erratic factory placement.

What datchew said first was the important thing. Depth of the cannister in the engine block. This was also written up very clearly by Oak in Airmail this January.

The cannister is supposed to be installed at the factory to a depth of 3mm. But subsequent measurements by many people have shown this figure to be all over the place.

My friend's '77 RS measured at 2.9, he was finding his O-rings and shim were really looking mangled after every change. He has started re using the paper gasket, that everybody has now stopped using.

I just measured my '81 G/S this week and found I was at 4.2mm. I have now put in 3 shims.
The recommended compression value for the O-ring should be between 10 and 25%.
A new O-ring should be 4.0mm exactly.
A new shim is 0.30mm
My formula for 3 shims is : 4.0(o-ring) plus 0.9(3 shims) minus 4.2(my depth) equals 0.7 divided by 4.0=0.175 times 100=17.5%
This seems to be within the ball park.
Prior to this there was a risk of low pressure with just one shim as my percentage was 2.5%. I have been lax in reusing my O-rings as they always came out looking like they went in. And as I now realise it was because they weren't being compressed.

Datchew with 3 shims has a compression of 15%, so he could go to 4 shims if he wanted to.

Chris

[AliBaba]

I agree that using multiple shims are better then doing nothing.
According to two of the best engine-builders in Germany (HPN and Motoren Israel) this is not good practice.

If the gap is big it’s probably because the canister has moved, and it will probably happen again. When you add shims you increase the risk of a moving canister.

Link from Motoren Israel: http://www.motoren-israel.com/produc...-erneuern.html

[Joerg]

Originally Posted by AliBaba

I agree that using multiple shims are better then doing nothing.
According to two of the best engine-builders in Germany (HPN and Motoren Israel) this is not good practice.

If the gap is big it’s probably because the canister has moved, and it will probably happen again. When you add shims you increase the risk of a moving canister.

Link from Motoren Israel: http://www.motoren-israel.com/produc...-erneuern.html

... and from the Tips'n'Tricks thread: http://www.advrider.com/forums/showp...9&postcount=67, in particular the link to the PDF on the HPN website.

[AntonLargiader]

With typical dimensions, the canister bottoms out around 4.2mm. It's inserted to some other depth and sometimes gets pushed deeper.

O-ring compression isn't as simple as most people seem to think, as the O-ring is already compressed radially before it's compressed axially by the cover. By my figuring, it is fully square around 3.5mm canister depth.

Adding shims is an OK solution (seems to work) but I don't like the idea of having multiple steel surfaces forming a sealing barrier against the oil pressure, so what I do now is pull out the canister and install a new one with a shim underneath to give a solid 3.5mm depth. Then just use the white O-ring, no shim, no gasket, no worries.

Lots of numbers on my canister web page:

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

Personally I think 3mm is too shallow, especially for the later canisters with the wider lip. There's nowhere for the O-ring to go, so it pushes the canister in (IMO). I've never seen 3.0 in a BMW bulletin (but I have seen 3.1~3.8).

[Sniper X]

This all doesn't apply to the 1985 R80RT does it?

[ignatz72]

Originally Posted by Sniper X

This all doesn't apply to the 1985 R80RT does it?

Yes.

[One Less Harley]

Yeah Yeah I know this is an old subject. !984 R80 G/S- Decided to look into the -o-ring thing since having to do an oil change. I've been using the gasket, white o-ring and metal shim as that was what was in the bike when I got it. Measured the distance from the case to the inner can and it was 4.1 mm...way to much. Note o-ring wasn't even compressed...duh. Before actually measuring I thought I could get away with just not using the gasket. After reading up I decided to go with THREE metal shims, white o-ring and no gasket. This set up had the o-ring proud of the case. I'm amazed there hasn't been a problem....thank goodness. I've put 20,000 miles on the bike this way and who knows how long before me.