Testrun

I know, I know.... oil and omp is kicking a dead horse, but lately I have been searching around and haven't seen much on the topic.
OMP with 2 cycle oil... Have we taken the viscosity of the oil into consideration when it comes to lubrication of the apex seal? I don't want a premix vs omp discussion or anything if the sort. Just curious as I have seen some housings raped with certain apex seals and these housings have the dedicated omp tank with 2 cycle oil instead if thicker viscosity "sump" oil. Could it be the 2 cycle is burning off too fast or not thick enough to properly lubricate the seal before the cycle is over? Speaking mostly of the spread of the oil as it hits at apex seal and spreads to the sides...... or attempts to spread out. I thought about going with a dedicated tank with 2 cycle oil, but I thought I would rather premix and have a thicker oil that may not burn off as quick in the omp. Carbon build up aside and any other points aside. I am strictly speaking of lubrication.
Thanks to anyone with some knowledge willing to answer this lol.

fendamonky

iTrader: (6)

Certain seals require more lubricant to avoid gouging the housings. If someone were running the "unbreakable" seals but only metering out the lubricant ratio intended for the OEM seals then they'd likely have problems, regardless of viscosity.

OMP vs pre-mix aside, if you swap to a more abrasive seal then you'll need to increase the ratio to avoid damage.

I would be interested in seeing manufacturers recommendations on pre-mix ratios for their different seals, both with and without an OMP. I know I'll be reaching out to my seal maker before my firsr start for their input. Obviously it's in the maker's best interest to provide this info so people don't come back with horror stories 5,000 miles later..

Carlos Iglesias

iTrader: (6)

While I assume you've seen it, I'll link the use/pre-mix instructions that come with the I-Rotary seals for others here:
Spic Racer GT40R - Motor, I-Rotary seals, EWP, bra-less, and foolish optimism

fendamonky

iTrader: (6)

I had not seen this post previously, thanks for sharing!! So 2-2.5oz/gal for the I-Rotary seals.

My previous set was the REC Super Seals and I was running 3oz/gal with them. This time I'm using those same I-Rotary seals. They shipped directly to the shop though, so I hadn't seen the instruction card yet.

Your posts are helpful as always, thanks!!

TeamRX8

iTrader: (2)

starting from this post:

https://www.rx7club.com/rotary-car-performance-77/scratching-my-head-over-what-apex-seals-pick-1133672/#post12374126

.

BLUE TII

iTrader: (9)

Softer seals just destroy the rotor housings.

With RA classic and RA Superseals in both 2mm and 3mm I tried factory S4 OMP adjusted to max injecting engine oil AND 50:1 premix (quart of premix when gassing up) and they still destroyed the housings. I was even running leaded race gas, which is another great lubricant

The soft apex seal material gets hot with the friction and welds itself to the chrome housings and then tears away (gauling) leaving a grooved surface.

I settled on factory 3mm seals. Strong enough the engine housings break before the seals on an engine without studs/dowels.

Testrun

I forgot are you running an omp?

Testrun

Also, I guess I am not getting my question out properly. I am speaking mostly of guys using 2 stroke for their omp. From a separate tank vs the thicker viscosity of the sump tank.
My thoughts are the 2 stroke oil is not with adequate viscosity when introduced into the chamber. I prefer my "dirty" sump oil.

I just did a compression on my motor with the REC seals. I am around 5k on the motor and did multiple hard runs through the dragon with a bit of engine braking in there. Lots of time in 2nd at 5-7k. Besides 1600 miles drive up and back cruising and 1000 miles break in the other miles basically multiple hard gear pulls. I am at 117/108/107 with the rotary tester on the front and I forgot the rear, but I know all are over 100. I have no idea the wear rate on these. If I could do it over again I probably would go with oem 2mm. If I can get a couple years on these and only have to replace housings and seals I wouldn't mind sticking with them.

I premix 1oz per gallon idemitsu and I use RP synthetic with the omp cranked up a bit.

Testrun

Your road racing and hill climbing correct?

fendamonky

iTrader: (6)

No OMP on mine, just premix with a smidge of fueling on decel for lube there.

Testrun

That's right. Some day I will remember the majority of what everyone has going on.
I have to double check my decel.. if your on a pfc you mind sharing whatcha got?

BLUE TII

iTrader: (9)

Autocross and hillclimb, but really it was all the 4th and 5th gear highway pulls putting a strain on everything.

Testrun

I would think autox with the engine braking in there would do it. 5th gear pulls . I am actually a bit suprised the compression is down that much, but it still has some life. These seals are definitely drag race.
So that leads me back to the question of 2 cycle vs thicker viscosity omp.... and if your running meth at all with the water how much is being washed off. I am just curious as the reason why people started going with the separate omp pump to begin with... with the 2 stroke.

You would think the aircraft would put more strain on them. They have a tbo on the engine for sure, but nothing like 20hrs which i have seen some seals rape the housings. Others claim 35k hard miles and still going

fendamonky

iTrader: (6)

Unfortunately I didn't tune it, and it's been down for a while. My FD is currently a few years into a MAJOR overhaul and the old PFC is long gone.

mr2peak

Sump oil isn't designed to be burned. 2T oil is. 4T will foul plugs, and lead to carbon build-up. That's why 2 stroke engines have a different oil. The correct choice seems obvious here.

You can turn up the OMP and inject more oil if you are worried it's too thin to be spread around

Testrun

I am glad you brought that up as this is what I am getting at. This thought process was brought on by the RX8 from what I understand. A lot of people just jump on the band wagon.This is something that is not a clear choice to me. Many people started the 2 stroke choice because the RX8s were having massive issues holding compression because our sump oil is causing carbon build up so someone along the lines said geee let's try 2 stroke oil as it is meant to burn... They tried it and guess what? The RX8 motor still built up carbon. It is inherent in the design of the Renesis.... the 7s simply do not have the same issue. Not like the RX8 anyway. This is what I understand. My 1st RX7 (NA) ran 198000 miles on it with me beating the crap out if it every day. Never premixed. I used quaker state 10w30 or 10w40... can't remember. This was 25-30 years ago. Only reason the car died was overheat from heatercore blow out. I drove it a few more miles over heating as I was ignorant (still am in many subjects) and it lasted another 3k after the repair.

So this is why I am asking has anyone thought or experimented with viscosity when it comes to omp? Or we just all on one of 2 wagons with no real proof behind it. I haven't found much on the forum or google.
I attempted to contact idemitsu about the 787 system, but I will have to dig deeper. They have no freekin clue. I know that is a whole different animal, but it would be neat to know. They had a separate tank..... but was it 2 stroke?

Makes me wonder about anyone injecting meth with a 2 stroke that can't handle it. Without viscosity a lot probably gets washed away. What is water's true affect regarding this? Would a thicker sump oil have a better chance of staying put and spreading out?

Like the argument of the min vs synthetic... i did an experiment myself and as stated before 2 of the synthetics left little or no residue compared to a couple mineral oils commonly used. So for me the choice isn't clear either. Also... is the majority of premix not synthetic anyway?

The great oil debate is in many ways so stupid to continue as many know these cars usually do not die from the type of oil, but the apex seal lube is something that I think a lot of peope just jump on a wagon. I know the omp vs premix is the same, but again I have to ask about viscosity.

These 2 topics are like politics 🤣

j9fd3s

iTrader: (3)

There is an SAE paper about the oil used in the 787B, so no it wasn't 2 stroke oil, they rolled their own

Mazda also did a study of the flow of oil in the Rx8 engines (spoiler alert, most of it goes out the tailpipe), Arghx posted it, but i'm too lazy to find it :P

Testrun

Just curious if it was the same as sump oil or a thicker viscosity than "2 stroke". Obviously, it is a whole different animal, but it would be cool to see.

Yeah the Renesis was not the best for this, but thats why they experimented with 2 cycle oil from what I gather. Thinking it would be "ashless" or not leave much carbon behind.

Testrun

I just spent a couple hours trying to find wtf Mazda used in the omp on the 787b with no luck. If anyone knows what it was I would love to hear it.

j9fd3s

iTrader: (3)

you are looking for SAE 922375, https://www.sae.org/publications/tec...ontent/922375/

Testrun

I have seen that article before, but doesn't really answer the question regarding viscosity regarding the omp.

I did have the opportunity to speak with REC today. Their seals according to them require approximately 1oz per gallon during break in and 1/2 oz after with omp. They use synthetics with omp. Idemitsu, RP, or Amsoil.

I forgot to ask their opinion on omp 2 vs 4 cycle.

Pete_89T2

iTrader: (4)

If I end up keeping my FC & FD long enough to to the point where I rack up at least 100K miles on each, and I tear them down for a refresh, I'll report back with what I find. It will be a LOOOOOONG wait, but then we'll have two data points on engine wear to help answer the OP's questions, at least specific to my engine's and their operating conditions.

The FC was a fresh build in 2017, with all new or nearly new engine components in a S5 13BT build with a pretty aggressive street port (intake + exhaust). I used all Mazda OEM engine seals & springs (apex, side, corner, etc.). Current hot compression is approx. 115psi on all faces, +/- 3psi, with about 18K miles on the engine now. The FC dyno'ed between 360~380RWHP, AEM Infinity EMS, BNR stage 3 turbo. I'm running the factory S5 OMP system (i.e., stock OMP plumbing & the 4 OMP injectors) with the RA OMP adapter kit, separate gravity feed tank for OMP lube. For OMP lube, I'll use any quality TCW3 rated premix lube, nothing fancy - typically the Pennzoil or Quicksilver Marine brand synthetic blend TCW3 lube that is available at any Walmart. Currently not running any additional pre-mix lube in with the gas, though I used to while I was still calibrating the AEM Infinity to deliver the correct OMP lube amount. The AEM Infinity OMP mapping is load and RPM based like the OEM ECU, and is calibrated to where I measure an average OMP tank lube consumption rate of 0.5 to 1.0 ounces per gallon of fuel consumed. This is what I typically measure in street and spirited driving sessions - during a dyno session, I've measured an OMP consumption rate as high as 2 ~ 4 oz. per gal. fuel burned.

The FD is very similar. Differences being the engine is a new (late 2019) unmodified Mazda 13B-REW short block with 5K miles on it now; hot compression is approx. 120psi on all faces, +/-3psi. This one also uses the stock FD OMP and a RA OMP adapter & tank setup, major difference WRT my FC is the FD OMP plumbing only has the 2x OMP injectors and lines, while the FC has 4. Engine management & OMP control is via a Link G4+ Fury EMS. The OMP calibration, OMP oil consumption rates and OMP lube I use is the same as described above for the FC. Haven't fully tuned or dyno'ed the FD yet, but with the BW SXE364 turbo it has and associated mods, it should be good for close to 400RWHP on 93 octane pump gas @ 15psi boost.