RotorWheeee

Quote:
Originally Posted by madcows
The only thing is that test isn't particularly accurate as they're testing it with air, which obviously has vastly different properties than motor oils.

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The test may have been done with air but the results are valid. Like to old saying which is heavier a pound of feathers or a pound of steel. The affect on the valve would be the same as the valve is activated by pressure. The difference between oil and air will show up in other ways like leakage around a seal, rate of flow...

just my two cents

PhillipM

Not exactly, there will always be some fairly serious leakage past those with air - they're just a slip-fit piston in a bore with no seals or rings after all.

Ash, have you got the dimensions? I can give you the difference if so from the damper prediction software.

madcows

My argument with the results is more about the fact the measurement is only an indication of the initial pressure required to begin by-passing. It still allows for higher oil pressures, though the linear increase in oil flow is compromised from the bypassing effect. This is why some people are able to see ~90psi even though the bypass opening pressure is around ~70psi. The oil pump flow rate is very much part of the equation, of course.

RotorWheeee

I don't disagree with what either of you have said, my point was simply how much pressure does it take to activate the valve. It doesn't change relative to how the force is applied. If you pushed on it with your finger it would still open at the same pressure. So it really a question of where you are measuring.

In the video it looks like what was being measure was input pressure, if so it would give you a higher input reading as it includes any additional pressure required to compensate for any leakage. I did mention leakage in my initial post but didn't have the knowledge of the valve design to know if leakage or something else would have a significant impact.

Always learning

EricMeyer

Am I missing something? I have never heard of an oil related failure with the Renesis. Please advise IF YOU HAVE SPECIFICS.

None of this "my neighbors babysitter's dad rented an RX8 one time from Avis and......"

bse50

The failures i encountered were always rear-rotor related. Rotor bearings, something similar to what was shown in the other discussion. Mainly a thermal pellet issue for who does short trips only.

I would like to know what's your opinion about oil pressure Eric, you surely see more high-revved engines rebuild than most of us here.

ayrton012

No, we have two oil coolers. I was talking about the modded single coolered cars (9krpmrx8, PhillipM)

ayrton012

Actually I reached the point that I have to say I don't understand why do you say that the rear bypass mod will increase the max oil pressure in the original 2 coolers system. I say this because we saw, that the modded single coolers system's instantly higher max oil pressure showed, that in the factory 2 coolers system the rear bypass regulator can't get opened. In the factory double coolers system the rear regulator never gets higher pressure than 72-75 PSI, and it's opening pressure is 78-92,5 PSI. So it stays closed. For this reason a higher rear regulator pressure won't help much in the original system, rather the front regulator mod or the pump mod. But better the cooler system mod.

I made my own test on my "spare" engine, to verify the 78-92,5 PSI rear regulator datas. Look at the attached pictures!

I know, this was not an accurate measuring, but I had not got enough time to do it better. The highest pressure that I saw on the gauge was 89 PSI (I was alone, so it was not easy to shoot the picture at the max pressure), but the bypass did not open even at this pressure.

ayrton012

But you have 90 PSI, and we have max 74 PSI with the factory 2 OC's system.

ASH8

Ok, Yes Phillip, and now 9K are confusing the issue, because Most will not be aware their system is Different and I would prefer this thread not to be contaminated with their system, this thread is about RENESIS 1 condition.

MY EPC is for UK and Australia, not Europe or Germany, so I have to rely on what others tell me, here in Australia as you know we only have ONE Oil cooler for all Series 1.

Mate, I really get tired of Bloody saying the same thing, yes, I put up pics of an FC open sump showing the same rear by pass valve as used in the S1 RX-8, 3648-14-250 for the THOUSANDTH TIME..

Europe has this same valve, so who do we believe, your test, or what Pineapple racing did with the CRUSHING of the 3648-14-250 VALVE, and what factory manuals say???

They (Pineapple) say it goes from about 66 to 88 PSI with mod, you are saying with your test it is already at 85 PSI, but One you are not using the same Air Guage or attachment they use.

Aryton, do you want the video link again from Pineapple Racing??

And I appreciate your info, but somewhere the issue is being corrupted, so who is one to believe, a business who does this for a living or you???

It is a fact (according to RX-7 ws manuals that this valve 3648-14-250 is around 60 PSI, the S1 RX-8 FACTORY Manual says 64-71 PSI...so I have NO Idea where you get 85 PSI with NO Modification...

I suggest maybe your technique is not the correct method and or your Digital Guage needs recalibrating?

ASH8

By my conversion 5.94 BAR is 86 PSI...I give up!

madcows

I might be with Ayrton here, guys... And ash, I would have to say that it has a lot to do with with stock S1 oil cooling. What Ayrton is pointing out is that if you want to increase your OP on a stockish S1, you have to do the front bypass mod, as without it, the rear bypass mod would be useless.

Ayrton, Can you run a similar test applying pressure to the oil send off the front housing(is that where the oil send is located?)? You might get some leakage through the oil pump, but you might still be able to somewhat test the front regulator that way (unless the oil pump leaks too much air).

olddragger

iTrader: (3)

wasnt that the plan all along--you have to use the spacers on the front by pass before you mod the rear?
Also good idea to increase the oil filter by pass pressure (we are using thicker oils etc etc)
and to look at the oil cooler thermostat.
Its a system.
OD

9krpmrx8

iTrader: (46)

I agree OD, you have to address the whole system.

ASH8

Yes, as the tutor man from Pineapple says, in doing the rear valve you must also shim the front, then you have Paul and Mr E saying the front Oil Pump Relief Valve rarely goes off, only if there is an issue somewhere in the Oil Circuit..like maybe a leaking Oil Hose or Leaking Oil Cooler, or even a blockage?.

As I see it Ayrton was pointing out that with his test he is seeing more than 85 PSI with his air hose demo, where Pineapple calls it 68 without the mod, 88 PSI after the Mod ??

I also agree that the TWIN Oil Coolers appears an issue in lowering the OP, 9K and Phillip have proved that one, but then you get Giorgio showing his OP at a consistent 5 bar while doing a WOT run?...as far as I know he has done No Oil Circuit Mods.

So why are the Italians seeing Higher pressures than those in the US?, same parts, different results, the only other variance as I see it are engine temps and oil viscosity???,

I really do not think this is the case, But, surely the "brand" of Oil Filter could not be corrupting the OP readings?...could it??, would say a new Oil Filter with no caught particles in filter cartridge paper give a lower reading to one Oil Filter that is say 3000 plus miles old??, with possibly less Oil Flow through the filter paper itself?

What also concerns me are 09 (Series II) owners installing the incorrect non-genuine Oil Filter from say Mobil, Bosch or Fram which has a MAX By Pass Valve/Spring of around 17 PSI where is should have an Oil Filter with a MAX 26 PSI By Pass, could the higher Oil Pressure (OIL Flow) cause the Filter Cartridge to Lift and By Pass oil prematurely, and therefore NOT Filtering the engine Oil as it should?

ASH8

I agree Denny, it should All be looked at and modified if you are going to go down this path, which IMO is a very good move..

To answer Mr. Meyer's question,
The evidence (pictures) have shown very premature wear (down to copper) at 50,000 miles at the eccentric shafts stationary gear bearings and in some cases rotor bearings in the USA and UK, given the fact that these parts are up to 40 year old (4 port S G Bearings) and from FC and FD RX-7 Turbo ( S Gear and Rotor Bearings) why are we seeing this wear?.

As a group we have discovered that the By Pass Valve (rear) is FC RX-7 as is the Oil Pump Rotors (therefore displacement), it appears there are a combination of reasons, Oil Viscosity (particularly if 5W20/30 oil is old), the additional Oil Cooler is also lowering Oil Pressure.

And the fact that Mazda have completely overhauled the Oil Pressure and Oil Circuit in Series II (09) RX-8's by increasing Oil Pressure by 50% (at Rear Engine Oil Intake), along with all new two external Electric MOP's and 12 Volt semi external OCV (Oil Control Valve), larger Oil Filter and Higher By Pass rated, the Series 2 RX-8 also has No rear By Pass Valve....all other Internal Engine parts and seals have not changed between the two series.

Many of us believe the Series 1 RX-8's are "starving" or 'lacking' Oil Pressure or Oil Flow through the e-shaft bearings otherwise why did Mazda increase the internal Oil Pressure by 50% in the RENESIS II?.

madcows

I'm starting to suspect that these bypass valve springs are from China.

ASH8

Why not...everything else is...or soon will be...the world owes all it's money to China......doesn't it...

ayrton012

Thanks Madcows.
Maybe next weekend, I will try the front regulator. But I don't know, will my compressor's capacity be enough?

ayrton012

They don't see higher pressures. 5 bar is 72,5 PSI. We all see about the same max pressure with the factory double OC system, in all over the world.

ASH8

9K (USA)
9K with 2 Oil Coolers was not seeing consistent Oil Pressures, you guys were slightly higher.. see his graph...not mine..

https://www.rx8club.com/showpost.php...7&postcount=90

Now he has gone to a 'Single' Middle Oil Cooler his OP numbers have increase higher..without any mods to By pass Valve or Relief Valves.

bse50

Ash, i see 72psi\5bars with a double oil cooler system (stock here in italy). Did you think that i've got a single oil cooler rx8?
Anyway i would follow OD's way of addressing the whole circuit as a system, that's why i'm waiting for Mazmart to put his "remedy" on the market. He will surely explain why he picked up a determined combo!

EricMeyer

Thank you ASH8. I am more clear now.

So I just read all these posts again. Here is what I hear:

-SOME motors have seen a fair amount of bearing wear.
-It is assumed that this is an oil pressure/oil delivery issue
-There is various and conflicting data from engines marketed to different continents.
-These differences may or may not be related to testing procedures
-The 09 system is different and is believed to be an improvement resulting in a cure of the bearing failure

Question: Could we talk about the problem a bit more? I'm wondering if this bearing problem is global or regional or is observed in a very small percentage of engines.

I am under the impression by some very talented people who are close to Mazda engine engineering that 9 out of 10 failures of Renesis engines in the US and are sent to the warranty rebuild facility in Virginia are low compression engines with Apex seal carbon deposit issues. Perhaps the bearing issue is absent, overlooked, unreported or these engines seen in Virginia have yet to experience this issue.

bse50

Dear Eric,
The bearing problem seems to be a regional one. Here in Europe we tend to travel smaller distances that don't completely allow the e-shaft's thermal pellet to open. Small and frequent travels do increase rear bearing wear. Traffic jams also contribute to carbon buildup but we have plenty of twisty roads where you can let your engine work with different loads and at high rpms so that's not always a problem.
On the other hand, american users that do a lot of highway at constant\low rpms see another engine killer problem, carbon buildup. The longer distances let the thermal pellet stay open for most of the time.

That's what i think is relevant for this issue, the extra 1000rpm could be a good reason to uprate our oil pressure considering how the fc3s ran (lower limiter, thicker oils).

Does it make sense?

Giorgio

Mazmart

iTrader: (12)

This is why I like you Eric: You tend to take a systematic logical approach to everything.

There is not an epidemic case of bearing wear but a great increase for a 'given' milage range. My research suggests the oil viscosity choice as the primary reason. Advanced seal wear and excessive carbon buildup is still by far the reason why more renesis motors aren't running to 150k plus miles (A lot won't see 100k). We are seeing the bearing wear in all the typical areas, just at lower milages. Mr Engman identified it as a viscosity issue 5 years ago and has only deepened that opinion over time.

Some have concluded that they need higher oil pressure and I'm not opposed to the concept whereas it is not essential for most.

Paul.