Filter bypass, think of the way a blower bypass valve works.
The filter bypass opens when the pressure difference between pre-filter and post filter is greater than the spring pressure.
The filter bypass opens due to a clogged oil filter.

 

Actually the problem is the low oil pressure in the e-shaft, I think.

 

In this case, why are we seeing 71 PSI on the gauges, instead of the 78-92,5 PSI controlled by the rear valve.

Where is the 65-71 PSI control valve (regulator) in the S1's oil system, if the front valve has 156 PSI (emergency), and the rear valve has 78-92,5 PSI?

A lot of people see max 71-80 PSI oil pressure, so this 65-71 PSI control valve could not be a print error.

 

May be gauge error or pressure drops through the lines, we certainly see the full 90+ psi at full chat.

 

But there are in the Service Bulletin's by Ash a 63 or 65-71 (I don't remember exactly) PSI limiter, and a lot of people (like me) say max 80 PSI on their gauge.

...and pressure drop from an emergency 156 PSI to 71 PSI? There is no reason for it. It is too much. ???

 

I imagine that the valve is unable to dump the full volume of oil supplied by the pump at ~70 psi, in which case you would see a little bit higher pressure on your gauges.

 

I thought I had seen 80psi or more on the course but I have not been able to recreate those numbers. No matter how hard I ride I see the same 70psi or so when driving hard.

 

This is the table that confused me (attached).
According to this, we have an oil pump pressure regulator with 64-71 PSI in the S1 Renesis. We call it front regulator valve. Our gauges show that this is the valve that determines the max oil pressure in the S1 Renesis, because our max pressure is between 71-80 PSI.


So what about the rear regulator? Is this table wrong, and the 64-71 PSI regulator is the rear one instead of the front, and we have the same oil pump regulator (front valve) like in the S2 (156PSI or something high open pressure emergency valve)?

Paul said that the front valve usually never moves, so if it is true, we can't have 64-71 PSI oil pump regulator (front valve).

One thing is sure (according to the gauges), we have an 64-71 PSI regulator in the system, but where?

 

As I have said before IMO this table is in error..

The Front "relief" valve should still be set to relief in the event Oil Pressure Exceeds 156 PSI, the reason I say this is because FC, FD RX-7's are 156 PSI and IMO earlier rotaries have had a similar relief valve pressure...as Paul says in the event of a failure in the system somewhere this front valve opens to relieve pressure at 156 PSI.

I somehow don't believe the Series 1 figures listed are for this O Pump Relief, but are for the REAR By Pass Valve.

Remember the series II does not have a Rear By Pass Valve, but an external OCV (Oil Control Valve) on the Left side on top of front timing cover, this valve is a Spool Stepper Valve arrangement that controls by pass to oil pan and also oil supply to the two EMOP's and has an Oil Diversion or Cleaning Mode, and I can't find the "Actual By Passing Pressures" for the Series II, even in the 09 factory WS manual.

All I can find is the Oil Pressure reference is 50% higher than S1 at 212F @3000 RPM, 72.5 PSI to 50.8 for Series I, this is where I believe the S1 can cope with an increased Rear BP pressure of around 20 PSI, some don't agree, but as I have also said all internals of these two engines are the same and could cope with an OP increase.

 

Thank you, now it is almost clean.
Almost, because the European Service Bulletin writes about a 78-92,5 PSI OR MORE !!! control valve, but everybody who has gauge see max 71-80 PSI oil pressure. So is it a print error, or (and) we have a 64-71 PSI regulator in the system which justify our gauges?

"• An oil pressure regulator has been adopted on the rear side housing to release oil when the oil pressure is 538-638 kPa {5.5-6.5 kgf/cm2, 78.0-92.5 psi} or more."

 

My car is a european one and never sees oil press temp above 4.9\5bar...
That should be a misprint

 

As I have said the rear valve 3648-14-250 was last used in an FC (in Mazda Parts Model code originally from a 1976 13B RX-4,5), so if it is the same it is the same.

So what ever the by pass was 33 years ago, it is the same today.
This is my point, you have a Rotary that Revs far higher than 33 years ago but with the same oil pressure in the e-shaft.

IMO for Internal Oil Lubrication and Oil Cooling it should be slightly higher, because most owners are actually 'Using' this higher rev range.

Your Diagram is a good one to show how it works and why crushing or shortening the spring travel will increase BP Pressure.

 

I did a little test very early this morning and once my temps were steady at around 180 degrees, I did a couple of hard runs to 8300RPM and then one hard run redlining each gear to 110MPH and at full song I was a tick under 80PSI.

 

everyone please remember --load on the engine does not affect the oil pressure--so free rev's will show you the same thing.
The 8 does like cooler weather though
OD

 

I just don't like free revving my motor, makes me nervous.

 

Better than spinning it up fully loaded?

 

I may be a weirdo but it just feels like something is gonna break when it's revved freely.

 

So if we should know the max oil pressure (by gauge) in an FC, than we should say that the 78-92,5 PSI S1 regulator data is a print error in the European Service Bulletin, and the 64-71 PSI regulator data is the good value.

Actually our gauges justify the 64-71 PSI regulator, so it's strange how Mazda informs its own services in the actual Europen WEB Service Bulletin (MESI).

We need max oil pressure data from FC owners with gauges, PLEASE!

 

As mine. 5,1-5,2 Bar max.

 

Mazda Europe? they don't know squat about rotaries and some of the service bulletins show it fairly well

 

Sure. But the at least the datas come from Japan, I thought.

 

This should be true but how much data is "interpreted\translated"? How much sees the revision due to political\marketing strategies? (ie, 1service every year\20.000km).
Our compression chart shows both the minimum and maximum graph line, while the american manuals i read only show one of the 2!

Strange things... anyway the oil pressure is what is reported by the almighty ASH8 so the 9x psi debate is just a moot point.

 

True! I'm dissapointed in Mazda (not in my RX-8), I never beleived that I have to recheck any datas what I find in the official service bulletin.

 

Since there is also some speculation that residual oil in the oil coolers and lines is contributing to the problem, is there a way to implement some kind of drain plug or spigot at the oil coolers?

 

20w50 FTW !!

Argh, not gonna turn this into another oil fight ... 20w50 FTW !!! ...argh ... fine I will leave ... for now ...