Oil Pressure

[Garnet]

Does anyone know what the micron rateing of our filters is, or should be?

Perhaps there is something going on with the filters. Back in the days that our bikes where designed 20-50 oil was very common and suitable filtration was designed for that thick and even thicker oil. Today 0-20 oil is common and 5-30 is diesel oil, could it be that filter makers are useing paper that is much finer than was used in the past.

Just thinkin out loud.

[bbelk]

I am curious why you put straight 40w in there, Brad.

In all my cars, somewhere around 100K miles I have switched to straight 40w. It quites the lifters and according to my dad, a mechanical engineer, thicker is better. That and its hot here in Texas.

As for the Airheads, I think I remember someone on this forum suggesting it. The filter issue never occured to me.

On the long ride last week, I was starting every morning in the 40s and 50s. It was near 80 when I went to the car wash and had the problem.

I was supposed to head out on about a 700 mile (round) trip to Louisiana to go fishing tomorrow on the bike. I think I will take a car until I can get a little more run time to see if proper oil solves the problem.

[mattcfish]

Well, instead of dicking around removing the detent ball and all, I blew air through there. It was clear. And yes, the gauge screwed into the block was educational. Lots of difference hot and cold with the 20-50.
The tube down the center of the filter is not the answer to the problem, but it sure is nice to know the filter can't go flat like the full length ones did and hopefully the hinged ones won't fold in, rupture and puke filter and aluminum bits into the block. I'll take a squared one like bbelk's over a flat one or ruptured one any day.

I really wish I could help.
Maybe it's time for one of these? http://www.motoren-israel.com/product_i ... ilter.html

[Deleted User 287]

In all my cars, somewhere around 100K miles I have switched to straight 40w. It quites the lifters and according to my dad, a mechanical engineer, thicker is better. That and its hot here in Texas.

As for the Airheads, I think I remember someone on this forum suggesting it.

Those would be hydraulic lifters your dad was talking about, I'll bet.

As for airheads, I usually refer to the riders manual when in doubt.

[Major Softie]

Does anyone know what the micron rateing of our filters is, or should be?

Perhaps there is something going on with the filters. Back in the days that our bikes where designed 20-50 oil was very common and suitable filtration was designed for that thick and even thicker oil. Today 0-20 oil is common and 5-30 is diesel oil, could it be that filter makers are using paper that is much finer than was used in the past.

Just thinkin out loud.

The "fineness" of the paper is not related to the viscosity of the oil that will be passing through it, it is directly and only related to the fineness of particles the filter is designed to filter out. This is specified by manufacturers on a basis of the percentage of particles of a certain size (microns) that the filter will catch. The filter will meet that spec regardless of the viscosity of the oil.

How much oil can pass though the filter, and how easily, is then a product of the surface area of the filter paper.

[bbelk]

The "fineness" of the paper is not related to the viscosity of the oil that will be passing through it, it is directly and only related to the fineness of particles the filter is designed to filter out. This is specified by manufacturers on a basis of the percentage of particles of a certain size (microns) that the filter will catch. The filter will meet that spec regardless of the viscosity of the oil.

How much oil can pass though the filter, and how easily, is then a product of the surface area of the filter paper.

I have no knowledge to the contrary, but this doesn't sound right to me.

[Garnet]

The "fineness" of the paper is not related to the viscosity of the oil that will be passing through it, it is directly and only related to the fineness of particles the filter is designed to filter out. This is specified by manufacturers on a basis of the percentage of particles of a certain size (microns) that the filter will catch. The filter will meet that spec regardless of the viscosity of the oil.

How much oil can pass though the filter, and how easily, is then a product of the surface area of the filter paper.

My knowldge lies more in automtive filtes, spin ons in particular.

According to a tech from Wix, 75 to 85% of oil bypasses the filter when the oil is cold as it is too thick to pass through the filter media. There is difference in spin-on filter design that is not seen. One important feature is to have the built in bypass valve at the bottom of the filter so that oil must pass through the centre of the filter to get to the bypass. This warms the filter faster and leads to the bypass valve closeing sooner and full filtration taking place.

This is old school thinking. I would imagine that the latest genneration of (auto) engines, which all use new filters after 30 years of few new part numbers, are designed to stop the bypassing even eralier. Part of that solution (my guess) is the very thin oils specified, and the matching fiter media.

When a fiter company plans production runs they natuarly plan around their largest market. If that is automotive, they probably make many thousands of auto filters for every MC filter, and buy supplies to suit. It would seem plausabile that the same media may be used in both.

Unfortunatly I know no one at Wix any longer who would know those answers.

[Major Softie]

The "fineness" of the paper is not related to the viscosity of the oil that will be passing through it, it is directly and only related to the fineness of particles the filter is designed to filter out. This is specified by manufacturers on a basis of the percentage of particles of a certain size (microns) that the filter will catch. The filter will meet that spec regardless of the viscosity of the oil.

How much oil can pass though the filter, and how easily, is then a product of the surface area of the filter paper.

I have no knowledge to the contrary, but this doesn't sound right to me.

Sorry. Too bad.

[ME 109]

How much oil can pass though the filter, and how easily, is then a product of the surface area of the filter paper.

The effective filtering/flow surface area of the paper could become hugely reduced if the pleats were to press together.
Each pleat is a fold and there is not a large void on the inside of a fold.
That would leave the bottom of the valley between the pleats as the only exit for oil.
?

As this has happened to two brands of filter on the same bike, it rules out a defective filter imo.

Cold, thick oil and high revs is a possibility, but that has been discounted I believe by the afflicted.
The oil filter bypass would also have to be overwhelmed in that case.

The oil filter bypass ball is held in place by 'differential pressure' er, actually it opens because of differential pressure and is held in place by eqaul pressure, and a little help from a spring.
The pressure relief valve on the front bearing web maintains 70? psi for the oil going through the filter to push against.
If the pressure relief valve momentarily stuck open some how, would the resultant pressure drop downstream from the filter cause a higher pressure upstream of the filter?
I see it as every pound drop in pressure from the '70 lb psi' pressure relief valve, is one pound extra pressure on the filter paper?

Maybe differential pressure is what keeps the pleats apart?
Man, I may have just discovered a completely unknown theory dead end.

As no one? has really nailed this one, I can't help but put my nutty professor hat on.
Sorry Barndead.

[barryh]

The effective filtering/flow surface area of the paper could become hugely reduced if the pleats were to press together.

You can imagine from the picture of my crushed filter tube that the some of the pleats were flattened against the tube so reducing the surface area.

How about this for a theory. The pleats only have max. strength when they are uniform and straight. I noticed that even the pleats which were not crushed were distorted into a lazy "S" shape possibly by excessive axial pressure from having missed out the cover gasket. The big O ring came out square and touch extruded so I'd obviously got the canister depth measurements wrong and subsequently went back to using the cover gasket.

So if a filter is installed with excessive axial pressure which distorts the pleats then strength is compromised and the excessive revs with cold thick oil senario is more likely to collapse the filter.

Shouldn't the filter construction prevent axial pressure distorting the pleats ?

Probably but that might depend on the quality of the filter.