Oil Filters

[kiwipom]

hi guys, some time ago i made a filter based on similar on the market, here are a couple of pics, cheers

[duTch]

 

  rather large`a 1/4 house, cheers

   Reply #25 now edited for proof readers         (HOSE- Mansion brand edited)


 Nice Filter KP- is that based on the Rocet3 filters # 70-6571 ?     and did the Tridents use similar insert (?)

[RogerSB]

OK, here's one! What about oil filter element by-pass pressure. High or low best for our bikes oil return?

[Triton Thrasher]

OK, here's one! What about oil filter element by-pass pressure. High or low best for our bikes oil return?

Shouldn’t matter.  You’re not going to run with a completely choked filter?

[RogerSB]

Shouldn’t matter.  You’re not going to run with a completely choked filter?

Hopefully not but I always wonder about this:-

If the differential of oil pressure into the filter to out of the filter is too high then the by-pass valve opens allowing oil to by-pass the filter .  What if a new, clean filter's designed by-pass pressure is too low for the return oil pressure from the engine? .  The valve would open allowing oil to flow.  We look in our oil tanks and see a nice flow of returning oil . Would that not make it important to have a filter element fitted with the correct by-pass pressure for a particular engine?


Just a thought.

[Triton Thrasher]

What if a new, clean filter's designed by-pass pressure is too high for the return oil pressure from the engine? .  The valve would open allowing oil to flow. 

I don’t understand.

[RogerSB]

I don’t understand.

I'm not preaching here as I'm not sure myself but here's how I think about it - and I may well be wrong. Also please substitute too low for too high in the quote (I'll amend in my post).

For example with a filter element with a designed by-pass pressure of around 23 psi the valve reacts when it senses a certain resistance (say a blocked filter) it then allows oil to by-pass the filter so it can continue to flow. On the other hand if you fit a filter with a designed by-pass pressure of a lot less, say 10 psi, and your return oil pressure is higher than that wouldn't the valve sense the higher pressure and trigger a by-pass

I know filters for different vehicles have different designed by-pass pressures so it can't be just about whether it screws into the housing ok.  Most of the filters we buy, for example for the RGM Norton type of housing, were actually designed for cars, such as the 2CV, Dyane, Peugeot, Talbot, etc.

[duTch]

 Bypass pressure lower than a BSA- you kiddin' ? 

 Fairly sure that was what Sluggo was suggesting a little while ago, maybe go read his posts on the matter

[Greybeard]

Isn't a filter bypass, if fitted, usually in the header; a ball and spring? I don't see any kind of bypass in the filter cartridges I use.

[RogerSB]

Bypass pressure lower than a BSA- you kiddin' ? 

What is an A10s oil return pressure back into the oil tank? I don't know - but I'd like to know.


GB, attached is a diagram - but not a very good one I'm afraid.

[KiwiGF]

Bypass pressure lower than a BSA- you kiddin' ? 

What is an A10s oil return pressure back into the oil tank? I don't know - but I'd like to know.


GB, attached is a diagram - but not a very good one I'm afraid.

The bypass route in a filter only operates if the filter itself restricts flow through it to the extent the pressure drop across it exceeds the designed bypass pressure, it makes no difference what the pressures are elsewhere in the system. So if the bypass filter operates at 10psi, then the bypass will operate when there is 50psi one side of the filter and 40 the downstream side, or 30/20 or 20/10 etc etc.

If there is a restriction downstream of the filter (say in return pipe the inside the tank) then this will raise the pressure equally throughout the system so BOTH sides of the filter, thus not affecting the bypass operation at all.

[worntorn]

So perhaps if the same filter was left in for 100,000 miles it might start to bypass?

Regular old bike oil changes (2,000 miles max for me) and filter change with every other oil change and the bypass shouldn't ever come into play.

[duTch]

 

Quote from: duTch on Today at 07:48:41

    Bypass pressure lower than a BSA- you kiddin' ? 

What is an A10s oil return pressure back into the oil tank? I don't know - but I'd like to know.

 Ok I was being flippant   aka 'takin' the *** (out of BSA)

 I imagine it should be easy enough to add a 'Tee' piece into the return line with a pressure gauge attached- if one should be so inclined ?
 To be honest I don't think there'd be much pressure at all, as there's not really anything to restrict the flow until it reaches the filter, and the scavenge side of the pump is more of a 'volume flow'  .

 We also have to keep in mind that probably *most* engines with filters have wet sumps, and the filter downstream from the pump before the feed to the engine/bearings, and the filter cops the full flow from the pump, which generally I'd say is 'feed only' - no scavenge/no need, so a whole different story (no real comparison).


 

[RoyC]

My son disabled the bypass valve on his firebird (I know it's a car) so that all the oil had to go through the filter.
One day he had no oil pressure, he checked everything to find out what was wrong. In the end he changed the oil filter and the oil pressure returned. The filter had only done 3,200 miles.
That means that past 3,200 miles none of the oil was being filtered.
From then on we have always changed our oil and filters every 3,000 miles.
So, how do we know how many miles a 2cv filter on a BSA is good for ?
Roy.

[duTch]

 

....So, how do we know how many miles a 2cv filter on a BSA is good for ?
Roy.

 I guess when you no longer see with your eyes no oil returning to the oil tank, it's time to call Houston...?