madcows

In my comments, I have completely neglected cavitation, and oil bypass - I was thinking of an "ideal scenario". Thanks to those of you who have corrected me. I would now like to find a comparison of pressure measurements from different weight oils. Unfortunately, figuring out just how much, and where cavitation occurs is practically impossible.


Ash, you got some great finds there! Thank you, sir!


On a somewhat unrelated note, I've recently been wondering what affect ******* the motor has on proper lubrication. I personally don't like running my engine anywhere under 2.5k rpm, unless I'm just crawling. With that said, at 3k rpm the S2 renesis is 22psi higher than the S1 - nearly 50% more pressure over the S1! All that extra lubrication can really help out those people who ride out in the highest gear possible - especially those that are forced to do so (i.e. the automatics). Anyone else like to enlighten me on their driving habits (what gears at what speeds typically?).

ayrton012

1.After all the confusion, it would be great to measure the actual oil pressure and max oil pressure in a S2 engine with a pressure gauge. Actually I don't believe Mazda so much, so this would kill the doubts, or justify the factory 150 PSI (about) data???

Please ASH, or anybody with an S2 Renesis, would you do a measuring in a service shop? It would be very helpful.

Otherwise I will try to take shims under the springs in the future, because I can immediately check the effects of its on my pressure gauge.

Can I simply change the (take out-take in) oil pump to an FC one?

nycgps

iTrader: (1)

nope.

olddragger

iTrader: (3)

what also would be interesting is the load versus rpm factor . S1 rx8 factory pressure spec is around 52 at 3K-----i wonder what is happening below 3K? Some folks may lug the engine (sub 3K) even though it doesnt feel like it?
If I remember correctly with a 10/40 W oil , 180F at 2.5K on a s1 the pressure was low to mid 40's? So maybe problems on both ends of the rpm band?
OD

ayrton012

On idle I've got 14,5-16 PSI with hot 30w (0w-30), but it goes up quickly with rpm.
As I know a normal crankshaft bearing needs only 10 psi at idle, but we have a more hotter e-shaft, so who knows?

ASH8

OIL PUMP??, you already have an FC OIL Pump????..

Are you talking about the Nut, Spring and Plunger, then YES you can remove it, but you have to remove your sump...It is NOT part of the OIL Pump BUT Controls it's pressure.

And you can try your spring shims.

As for OIL Pressure Numbers...
AS I have posted previously the 09 says 156 PSI
The 04-08 says 64-71 PSI..

What SHOCKED me was when I found a 20 year old Workshop manual on the FC RX-7 and it says it's OP is 156 PSI...same as the 09

Do you get where I am coming from.????
Either Mazda has Fecked up big time with the RX-8 or it is a printing error many times.

NOW, the SPRING in this CONTROL VALVE is RX-8 Specific by Part number, meaning it was new for the RX-8 S1, BUT, the Plunger and Nut is 38 years old and the same as an FC or RX-2,3,4,5,7...but not FD, it also has it's own SPRING.

The 09 DOES NOT have this Particular VALVE, it is in and part of the ALL New Oil Pump Assembly.

ASH8

Forgot to add, IF you want to change your OIL PUMP...Don't know why, you are talking a lot more work, front timing cover, water pump, pulleys.
Not even sure you can do it with engine still in.

Removing your sump for control valve access only should be OK there are no cross-members in the way and provided you can get your car up high enough or have use of a hoist.

madcows

Well, we can certainly ask anyone who has an oil pressure gauge on their S1 if their oil pressure has ever gone above the magical 71 psi mark.

Ash, I don't remember if you already posted it, but what is the max pressure on the FDs? I don't exactly understand how the FC would be able to supply 156 psi to the whole system when the regulator before the filter is designed to release pressure above 71 psi (or whatever it was). I wonder if the 156 psi control spring could work in both regulator locations on the S1. Having this in combination with an oil filter from an S2 might be beneficial. It wouldn't hurt my feelings if it helped my 80k miles S1 renesis live another 100k

Flashwing

Yep, I've topped out at 80psi.

ASH8

The front and rear valves are different, as in the plungers and springs and fitting housing are different...

From memory the front plunger piston 0839-14-115 is approx 30-40 % larger than the rear, the rear one 0221-14-115 I used to sell quite a few as it also does the Mazda Banger Oil Pump Valves for Mazda RWD 1000-2000 cc motors from 1964-1984 and even some later FWD banger models.
Mazda also regulates oil pressure by a changed spring size, but same plunger or piston.

See what I can find out about the FD oil pressure numbers, but this does have its own spring (front) like the FE S1 RX-8, the rear FD valve has the same 0221 plunger but the spring is not listed as a part number, I think the unit is also mounted in a different location for memory...will try and check on that one too.?.

ASH8

Back..
Well the on line WS manual are showing the FD with...

156 PSI Front Oil pressure Control Valve...same as FC, but FD has a different Spring Part Number.
110 PSI Rear Regulator Valve., and it is in the same location as the FC and FE S1 RX-8, spring may be different....no Mazda part number listed!

Don't forget the FD and FC Turbos have a slightly larger Oil Pump Rotors of 5 mm wider each, so higher volumes.

I wish I could place my hands on the 3 different front Oil Pump Valve Springs, so I ,we could compare them.

ayrton012

[QUOTE=ASH8;3286752}

You can also Upgrade the Oil Pump in Series 1 RX-8 to the FD or FC Turbo one.
The two Pump Rotors are 5mm wider each = higher displacement.[/QUOTE]

This was the reason why I asked it.
After that you wrote that we have the same pump. So it's confusing.

I have oil pressure and temp gauge and I have a spare engine, so I will try the shims without too much risk. ...and it is not too difficult to take the shims under the springs. I can do it, it was not my question.

But before any change we need real life ( by gauges) oil pressure datas from FC's, and S2 Renesis. The factory's reference datas is not enough.
We can not take another step forward without these real pressure datas.

PhillipM

I'm not going to have time to do this, hit a few snags with the rebuild and simply haven't got time, might be able to when the engine comes back out again over Christmas f no-one else has got the data by then.

olddragger

iTrader: (3)

s1's are maxing out at around 80psi from sender mounted below oil filter (isnt that past the rear regulator) this is with 20w/50 oil at oil temps below 200F. So regulator is doing its job.

I got to thinking--i also have a remote oil filter setup with to/from lines = approx3 ft--i see the same pressures as others but i am wondering if this may be hurting me?
I took my oil pressure gauge out sometime ago thinking i didnt need it cause I needed the room for another gauge. Maybe time for a reinstall!
OD

PhillipM

We touch 90psi on a sensor mounted at the beginning of the oil cooler line, if I get chance I'll shift one of them to the end of the line to measure the pressure drop across the lines, they're roughly 3ft long each, it'll depend what size your lines are though, we're using -12 hose.

olddragger

iTrader: (3)

mine is 10AN
This has got me looking for an 8 rib sc drive to reduce the tension on the nose of the e shaft. fixed or not --this is probably a good idea.
OD

HiFlite999

iTrader: (2)

I've been reading this thread with considerable interest. While searching for something else tonight, I ran across this how-to video that describes mods to increase oil pressure! Any comments?

http://www.rebuildingrotaryengines.c..._Oil_Regulator

ASH8

Understood, but remember we are talking about NA RX-8 and NA FC.
The FD (Turbo) uses the same oil pump from the FC Turbo.
And if you wanted to 'upgrade' to the "Turbo" Oil Pump you can and it will fit an S1 RX-8.

I also understand you want 'live' data, however I am comparing Component part numbers with each model, and the only difference when you take out the S2 RX-8 are the Front Oil Pressure Control Springs, even with the same FC Oil Pump.

So there are two different springs one for ALL FC RX-7's and one for all S1 RX-8.
The FD has its own spring also, everything else in these 3 cars are the same in regard to Oil Pump Pressure Control Regulators.

olddragger

iTrader: (3)

great find!
didnt the 93-95 run at about 110psi?
od

olddragger

iTrader: (3)

dont forget the 09 does not have a rear one
OD

TeamRX8

iTrader: (25)

hate to break it to you, but it's common for a Mazda part to have the identical part number and be revised, they don't always put the letter on the end to indicate a revision or change the number outright, including on the '09 ...

ASH8

Yep, so the oil going into the e-shaft (max) is 80 PSI, but as I see it the Oil going from the pump through Oil Coolers Etc should be at the higher PSI (this is my thinking with the 156 PSI (at Oil Pump Valve) in the FC, FD, and S2 RX-8).

So all those Zones have a higher oil pressure and it is cut down before it goes through the Oil Filter and the e-shaft which is where most of you Guys...well all of them are taking Readings from...after the Rear Pressure Valve and under your oil filters.

You need to put an adapter at the Oil Cooler Feed Line Banjo fitting (front Alloy Housing), or the fittings on the oil cooler (s), to get the Oil Pressure there!?!?.

Remember the rear valve on the FD is said to be at 110 PSI (not the 71 of S1 RX-8)...that is 30 PSI more, which I think the S1 RX-8 needs.

Look at the S2 RX-8 with NO rear valve but a slightly different Oil circuit and a top external Oil Control Valve which also supplies the 2 EMOP's which also returns oil back into sump and also has a self cleaning mechanism which needs oil pressure. And then the larger Oil Filter with Higher By Pass Pressure..

And yes , I know our oil pumps are "Positive Displacement" ones but...

It would be interested to see OD if when you remove the 3 feet of your remote oil filter if this effects your Oil pressure readings, before and after the removal???.
Remember at about the same engine temps.

I am still thinking this REAR By Pass valve in the sump on the S1 RX-8's should have either the FC or FD Spring, to push up the oil pressure for oil going into the oil filter and more importantly the eccentric shaft and then bearings.

Look for ALL we know the Series 1 RX-8 may be putting out the correct 156 PSI at the Oil Pump Outlet, Mazda Figures may be in error.
The only way to check is read the PSI at the OIL Cooler Feed Line.

The issue is the REAR Sump Valve IMO....improve this spring and you have fixed the Oil Bearing Wear Issue.

Do I make ANY SENSE???

ASH8

To put it more simply....for S1 RX-8's...

1. Oil is Sucked up by Oil Pump via Strainer/Pick up in Sump Pan.
2. Goes through Oil Pump, Control Valve sets pressure to 156 PSI, Excess Oil gravitates back to sump pan.
3. Then through Oil Cooler Feed lines at about 156 PSI, out of Oil Coolers "Cooled"
4. Then to Banjo Fitting at bottom of Rear Iron Housing
5. Rear BY Pass Regulator Cut's Pressure Down to 70-80 PSI, Excess Oil gravitates back to sump pan.
6. Then up through Oil Filter (where oil is filtered)
7. Then into Rear of Eccentric Shaft to Front and 2 Rotor Oil Jets, same lower pressure oil feeds supply to MOP

That is the OIL Journey under TWO OIL Pressure Zones.

ASH8

BS...it is not very "Common" at all, it is more common to see a Mazda Part that has had the Letter on the end changed, but when you compare Both there is no difference at all...

I can recall very few Mazda parts from the factory that have been revised without any change to the part number.

But Generally, when there is a letter change it denotes a parts change, then that can also signal a "suitability" or "supper-session" signal like AN or A, new parts can fit/replace OLD, but Old parts can Not replace/fit New, or there is NO interchangeability at all because they are totally different and this can happen from a part going from a D to an E on the end, they can be totally different.

Mazda never revises a Part that has changed and still in vehicle production without changing some part of the part number, if they did not do this they could not identify the vehicles that the revised parts were fitted to...it would be a parts and service nightmare.

Mazda Parts are Very, very good, not like GM or Ford or Chrysler...

ASH8

Yes, No change in the PART NUMBERS!! at all... over the 4 FD series I have..
That is Both Pressure Valves, and Oil Pump Assembly..

So one would guess there are no or very little PSI differences.