Oil pressure relief valve

[astontr6]

13 hours ago, Mike C said:

The original , bolt on , oil filters had no internal pressure relief provisions at all, and still worked - unless they got so clogged that all the oil diverted through the engine PRV- this has never happened to me but presumably the symptom of it happening would be the oil  pressure would rise to something like the cold start level.

But the trouble with that system was that it did not prevent oil drain down when the engine was stopped and over a period of time there was no oil left in the canister. Then you got bearing rattle when you started up, not good for longevity of the bottom end, hence Moss's cartridge conversion and the use of oil cartridges filters with non return valves in them! My oil pressure is 50 psi hot on tick over and 75 psi hot @ 2000 rpm.

Bruce.

[Waldi]

5 hours ago, DRD said:

What is the correct spec pressure for the bypass relief valve?

1bar or 2.5bar - the filters vary.

I assume you mean the by-pass valve inside the filter cartridges?
It think it is vendor (filter manufacturer) -specific. For a smaller filter, the differential pressure will be higher than for a larger filter, under all conditions. 

How much?
If the filter has twice the surface area (under otherwise fixed operating conditions and the same filter material), the “flow rate per area” reduces by 50%, which gives a reduction in pressure drop across the filter of 400%. And this is across the entire range.

This is why I have the larger cartridge because using the smaller cartridge is false economy. 

The original Triumph spring loaded valve on the left side of the engine is independent, it will limit maximum pressure, also important for the pump drive gear and shaft.

Hope this clarifies the matter a bit.

Waldi

[Mike C]

On 3/22/2020 at 11:00 AM, Casar66 said:

Has anyone an idea at which rate/pressure the prv opens?

I want to use an oilfilter with a bypass valve which opens at around 36 psi.

Many thanks

Carsten

Carsten,

Why do you need the relatively high 36 psi opening pressure? If a low opening pressure on the filter PRV causes a problem there might be another solution to the problem.

[Casar66]

I do not know what I need. People with kind of TR-expertise recommend me the 719/5 instead the 712. And I want to understand why the 719/5 should be better.

[astontr6]

On 3/23/2020 at 8:35 AM, Casar66 said:

Are you sure? Just yesterday someone with expertise told me different.

Yes that is correct there was no filter pressure relief valve in the original system that is why Moss and Co offered a cartridge filter system with a pressure  relief valve to stop oil drain down. The PI saloons and the other 6cyls. were famous for main bearing /big end rattle on start up. That does not do the bottom end a lot of good.  Never under stood why BL did not follow suit.

Bruce.

[Schnippel]

[Waldi]

Very good Ralph!

Waldi

[RobH]

Interesting. 

The Purolator oil filter housing on my 3A (which I discarded for a screw-on canister) does not have that fancy second spring arrangement. The plate at the base of the element is just plain with a dimple in the centre. Item 17  in the Moss picture, so no bypass action there..  

[JochemsTR]

Pressure Relief Valve in the engine: is located parallel to the oilfilter and should open around 72 PSI/5 Bar. Opening the valve gives way to the oil sump. So with a cold engine or high rpm the pressure remains under 72 PSI/5 bar.

An Oil Filter with a Bypass is exactly as Ralf described it. Note the comment "...blocked due to neglect.."

 

Edited March 24, 2020 by JochemsTR

[ed_h]

1 hour ago, JochemsTR said:

Pressure Relief Valve in the engine: is located parallel to the oilfilter and should open around 72 PSI/5 Bar. Opening the valve gives way to the oil sump. So with a cold engine or high rpm the pressure remains under 72 PSI/5 bar.

 

I often wondered what the PRV set point was supposed to be. Any idea what the range is?  My cold pressure is about 90 psi (measured with a decent gauge), and I've read of others with similar cold pressures.

Ed

[JochemsTR]

Hi Ed, not sure about the range....however, I would adjust the spring inside the PRV to open between 72 - 85 PSI....

maybe Ralf can give his input on this one....

Jochem

Edited March 25, 2020 by JochemsTR

[Schnippel]

Hi there
I usually set the (cold) oil pressure on new machines to about 90 psi.

Of course, this also depends on the oil used.

Ralf

Edited March 25, 2020 by Schnippel

[Schnippel]

On 3/24/2020 at 2:43 PM, RobH said:

Interesting. 

The Purolator oil filter housing on my 3A (which I discarded for a screw-on canister) does not have that fancy second spring arrangement. The plate at the base of the element is just plain with a dimple in the centre. Item 17  in the Moss picture, so no bypass action there..  

Hi,

look at No 6  there is the ball from your filter bypass valve.

Ralf

[RobH]

No Ralf - that is from the Tecalemit filter head on the left. The Purolator head in the centre doesn't seem to have that feature unless they just haven't shown it on the drawing. 

Edited March 25, 2020 by RobH

[Schnippel]

Hi

das ist ein Purolator Gehäuse.

 

[BlueTR3A-5EKT]

Standard internal clogged oil filter bypass/relief Item 106 on this page for TR5/6  https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/engine/engines-components/external-engine-tr5-6-1967-76.html

 

Warehouse Finds - TRF currently are selling NOS filter assemblies with the valve included  Pt No 129917  http://trf.zeni.net/TR6bluebook/21.php?s_wt=1920&s_ht=1080

Edited March 25, 2020 by BlueTR3A-5EKT

[AarhusTr6]

Hi

Looks like my PO removed my PRV, likely because of the fitting of the spin on oil filter.

 

 

[SpitFireSIX]

When I buy an oil filter I buy the one with the highest internal PRV setting over one with a lower rating.
I never want this valve to open. I never want the posibilty of unfiltered oil running thru my bearings.
It might operate on a very dirty filter due to neglect or: 
Because the oil is too thick for the running RPM.
If you are lucky enough to be blowing the engine PRV open at sub 1500  2000 RPM I would seriously consider a lower viscosity oil.
 

 

[SpitFireSIX]

On 3/26/2020 at 1:49 PM, AarhusTr6 said:

Hi

Looks like my PO removed my PRV, likely because of the fitting of the spin on oil filter.

 

 

The PRV "nut" is not shown in this picture. I doubt very much it is not there.

[Mike C]

The spin on oil filter is supposed to be mounted with the cartridge body down- to hold oil for start up.

I wouldn't run without an oil PRV- to preserve the oil pump drive shaft if nothing else.

[SpitFireSIX]

12 minutes ago, Mike C said:

The spin on oil filter is supposed to be mounted with the cartridge body down- to hold oil for start up.

I wouldn't run without an oil PRV- to preserve the oil pump drive shaft if nothing else.

Hi,

 I cannot run with the oil filter down. One way valve in filter?
Are you talking about the engine PRV or the internal filter one?

[Mike C]

The engine PRV. Most spin on adapters enable the oil filter to be fitted more or less vertically down- maybe with a slight cant to miss the clutch slave cylinder.

Probably the main reason most people fit spin on adapters is to minimize the engine oil starvation at start up. This is achieved by the body of the filter staying full of oil during shut down due to its orientation.

I don't know if relying on the filters internal one way  valve is a long term solution to start up oil starvation- unless the check valve is a very good seal the oil will drain out.

[Waldi]

I have a large slightly tilted mounted K&N oil filter. When the engine has not run for 1-2 months it takes a while before I have pressure on the gage. If the car was started say 1 week or less ago, it is there very quick. The K&N is new, but apparently the internal filter-prv allows oil to drain back from the gallery.

Waldi