High Flow Filter Relief Valve Combo - Radial Dynamics

For high flow steering pumps that require external pressure relief, this high flow filter pressure relief valve combo unit is an ideal option.

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Pressure relief valves are a critical component of every steering system to protect against over-pressurization but they are also one of the biggest producers of heat within the system. Most high flow systems on the market return the relieved fluid directly to the reservoir, skipping any fluid cooler plumbed into the return side of the system.

With this filter relief valve combo unit, steering fluid is relieved directly into the filter where it mixes with the main return fluid. Using this setup, 100% of the steering fluid, including the hottest fluid in the system, can be plumbed to a cooler prior to returning to the reservoir. This also eliminates one hose and multiple potential leak points from the steering system.

Plumb the inlet tee fitting (included) into your high pressure line and plumb the filter inlet and outlet as you normally would in the return side of the steering system. The selected spin-on filter is rated to handle up to 25 GPM (gallons per minute), more than enough to handle even the highest flowing steering pumps.

For critical applications, a Heavy Duty filter upgrade is available which replaces the standard 150 PSI rated Donaldson Filter with a medium-pressure 500 PSI rated spin-on element and matching larger diameter threaded coupler.

Don't forget to add an optional mounting bracket for easy installation.

***PLEASE specify desired relief pressure setting in order notes. Typical relief settings:

• Rock crawler/Ultra4 racer/trail rig: PSI
• Monster truck: PSI 

Assembly features:

• Grade aluminum construction 
• Pressure relief valve: - PSI adjustable (preset to PSI unless specified)
• Rated flow: 25 GPM
• 50% filtration efficiency (Beta2): 7 microns
• 99.9% filtration efficiency (Beta): 23 microns*
• High pressure inlet tee: -8 AN
• Low pressure return inlet port: -12 ORB (o-ring boss)
• Outlet port: -12 ORB
• Standard filter pressure rating: 150 PSI
• Optional Heavy Duty filter pressure rating: 500 PSI
• Replaceable spin-on filter

 *Beware of manufacturers claiming a "nominal micron rating" when in fact, there is no industry accepted definition for "nominal". Filter effectiveness can be described by efficiency at capturing particles of a certain size, or Beta Ratio, which is determined in accordance with ISO international standard.

I don’t see how it should matter. The oil pressure gauge is located in the chamber of the oil filter housing that comes directly from the oil pump, so it measures pressure before the oil filter. If the oil filter is clogged it will cause that pressure to rise as it restricts flow. There is always a pressure drop through the filter, but with a filter in good condition is should be low - a few psi. If that pressure differential across the filter rises to 10-15 psi, the balance valve will open allowing oil to bypass the filter element and removing the restriction. As a result, the oil pressure at the measuring point will drop by the amount formerly caused by the obstructed element - namely around 10-15psi.

I strongly doubt that an open balance valve will result in what we would regard as low oil pressure. An open balance valve just releases what would have been the excessive oil pressure ahead of the filter. So, if you notice your running oil pressure has been increasing slowly over a period of time and then suddenly drops by around 10psi it would be time to suspect that your filter is clogged and the balance valve has opened as a result.

I strongly doubt that it is the case if your oil pressure readings are generally on the low side. As far as testing it is concerned, with the type used in your S1 all I can imagine is removing it and visually inspecting it. It could conceivably be held open by some piece of debris, but that would have required it to be open at some point in the past due to a clogged filter.

Goto Tuomufei Valve to know more.

David, not knowing for sure, I am curious to these two statements. What I found in the Jaguar 3.8 engine section, page B45 simply says the balance valve opens at 10-15 psi. It does not even specify that it is 10-15 psi across the filter, which I would assume it is.
I was surprised when you said the manual states the oil pressure as read by the gauge would drop 10-15 psi. I would have thought the reading would have been the same, just increasing in proportion to the back pressure of the filter. Thus I was assuming the pressure gauge reading was before the filter. From what you are saying, the gauge is after the filter.
Am I missing something in the manual, or maybe I have a different manual, but does the manual indicate the gauge reading is after the filter, or do you know this by other means?
Thanks,
Tom

[edited after further thought] To all who have responded to my comment: I’m open to someone explaining where I’ve misunderstood things, but I am merely quoting what it states in the Jaguar Service Manual on pages: B.16 (bottom of page), B.46 (second paragraph), page B.47 (top of second column). It clearly states that (a) the balance valve opens at a “pressure differential of…” (so it is a differential valve), and (b) “this (the opening of the balance valve) will be accompanied by a drop of normal oil pressure of some 10 pounds per square inch” - this is stated in two places in the manual. I checked photos of the internal structure of the oil filter head fitted to the 4.2 S1s and it seemed clear to me that the oil pressure sender (screwed into the top of the filter head) is located in the chamber that receives oil directly from the oil pump - that is, it is measuring pressure prior to the filter. The balance valve separates the chambers for pre-filter and post-filter oil, and thus bypasses the filter when open. [edit] I think this is where I may have gone wrong, and need to check my conclusion that the pressure sender measures pre-filter pressure, rather than post-filter. If the pressure sender measures post-filter oil pressure the manual would make more sense as follows:

I agree with @Mike_Eck that the construction of the balance valve is a flow restricter which offers infinite restriction when the valve is closed (allowing no flow), and less and less restriction as the valve opens (allowing more and more flow). The restriction due to the valve results in a pressure drop across the valve which reduces as the valve opens wider. When in operation the valve opening will be in equilibrium where the pressure drop across the valve caused by the restriction it causes balances the spring pressure of the valve. The spring fitted to the valve is designed so that it stays closed until the pressure differential is 10-15psi. If the filter is clogged the valve will open but the restriction it causes will result in a pressure drop across the valve of around 10-15psi. An unclogged filter will only result in a pressure drop of a few psi, so the post-filter pressure will be around 10psi lower with a clogged filter than with a clear filter due to the additional pressure drop through the balance valve.

I went back and reviewed the photo of a S1 oil filter block and came to the conclusion that the oil pressure sender is screwed into the chamber that carries post-filter oil, so apologies for my confusing earlier post. This is the photo from the forum that I used that shows this:

Oil from the pump enters chamber B. from there is passes to the outside of the oil filter canister and returns down the center of the filter into chamber A. The balance valve screws into the hole between chambers A and B, and the arrow shows where oil will from directly from B to A in the event of a clogged filter. The oil pressure relief valve screws into chamber C and provides a path to the sump in the event that oil pressure exceeds 65psi or so. So, a clogged filter will cause the balance valve to supply unfiltered oil to the engine bearings but will lower the oil pressure by around 10psi from that provided by the pump. Essentially the balance valve limits the pressure drop through the filter head to 10psi at the expense of passing unfiltered oil.

I typed this earlier but did not have time to post it. Some is redundant to Michaels but i will leave it as it was. Michaels drawing is better.

David, thanks for pointing me to page B16, I see the statement. I do not understand it, but that may certainly be my lack of understanding the system. I do not follow how an additional restriction, a clogged oil filter, reduces the oil pressure to the pump.

This is how I understand the system. Note I have included two gauges, A and B for discussion:

As I understand it, the bypass valve will, when opened, direct oil flow around the filter when the filter is clogged. So as the oil pressure across the clogged filter increase it approaches 10 Psi across the filter. While this is happening, the oil pressure after the filter remains the same and is determined by the restriction in the motor bearings- let us say 35 psi.
So if no filter restriction, the gauge at A and B both read 35 psi. As the filter clogs, the pressure increases towards 10 psi across the filter. Thus gauge B remains at 35 psi due to bearing restriction, but gauge A increases to 45 psi. As the bypass valve opens, A still reads 45 psi, due to 10 psi across the filter and the bypass valve, and it must remain at 10 psi over the 35 or whatever pressurr.to keep the valve open. The bypass valve is operated by a spring. The further the spring compresses, the more force is required to compress the spring. So, if the flow is great enough to keep moving the spring further, the 10ps may increase to 15 pis, thus gauge A now reads 50 psi, gauge B still reading 35 pis. I see no point in which a clogged filter causes the pressure to drop at A.

As I just said, I would disagree with this implication
Yes it is a flow restriction, etc. But this seems to imply the pressure increases, which it does not. (Maybe it is just me getting this out of it)
The further the bypass valve moves, the further the spring must compress, which takes more force thus increases the pressure at the pump, even though oil is moving through the valve.

I have trouble disagreeing with what is written in the factory manual. They typically get it correct. I am very open to understanding why they have it correct and I have it wrong. I do not have Jaguar’s schematic of the oil system, so my assumptions of it certainly can be incorrect.

Help me out here.
Tom

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