GregW

I dont have any cool pictures or engineering data for you. Just real world experience. On a rotary those tiny holes for oil retention are peened shut by the hammer like action of the apex seals. They just dont have an agressive enough RA for my liking especially over time.

Every engine Ive built, even on brand new housings, I do a cross hatch. That mazda coating is crap compared to the same tech I find on a 1912 model T.

I would argue the real reason it was done was as a cost saving. Imagine trying to run each housing through a machine to produce a cross hatch. Yep, pretty damm spendy compared to mass producing it with a coating some super engineer came up with applied electricly.

Another reason it sucks is I cant just have it re machined and run a slightly taller apex seal.

Thinka about the 12A, Mazda is no longer making that stuff. That sweet coating on there is so super engineered that people cant even get it replaced. Yep, mazda knew what they were doing. Its called mass production as cheaply as possible while retaining an acceptable level of longevity and quality for the average person.

TonyD89

iTrader: (10)

I believe you're half right. It's the triangle pieces fault for the wear but I think other things are at play here. Number one being apex seal wear. As the top piece of a three piece seal or the long piece of a two piece seal wear, they allow the triangle piece to push up into the housing.

Remember which way that angle goes (triangle piece) and think about what happens when you start taking material off the top of the long seal.

As far as the center of the seal being the hottest, the proof is in the pudding. The top seal of a factory three piece is always concave to the housing because it's bowed the other way when in operation.

GregW

We are all passionate about the recipie each of us uses when modding an engine. Some folks absolutely hate premixing cuz its a hassle. Truth is, all these methods work and the arguing points are pretty minor considering a slightly modded car used for dd and some auto x. In that case, really, what is the binifit of premix other than easing the ocd of someone like myself. The owner still gets years of trouble free service but may see more wear than someone who dumped oil in their gas tank a few thousand times.

That RA kit would be fine if thats what makes you happy.

Casual_John

iTrader: (8)

With an OMP adapter you can still run whatever oil you want in the oil pan. I also have 3 windshield washer reservoirs to top-up, so a little 2-cycle oil reservoir is no hassle. The OMP reservoir would need topping up every couple thousand miles, not every time I add gas. That is easy too, isn't it!

Have you ever gone to a full-service station and told the guy to fill-r-up and dump this in too, please? Or told your girlfriend to do it?

Trolloc

y not just leave the stock OMP then premix a leaner mix like maybe 150:1 or 200:1 just to get a lil more lube evenly placed throughout the housing?

REAmemiya_fan

With stock OMP you should not premix under about 300:1

RotaryEvolution

iTrader: (30)

are you trying to say that the outsides of the seal are the hottest?

Casual_John

iTrader: (8)

Suppose I want to stop dripping dirty motor oil on to the rotors.
Suppose I want to burn cleaner oil.
Suppose I want to run synthetic oil in the motor.
Suppose I don't want to fiddle with another little bottle when I fill up with gas in the pouring rain or winter wind.
Suppose I rather go to a full service gas station.
Suppose I rather top-up an oil reservoir preiodically in the privacy of my own garage, rather than make a spectical of myself in front of everyone at the gas bar.
Suppose I want some of the benefits of premixing, without the regular hassle or embarassment involved with every gas fill-up.

I'm searching for a happy median. I don't think the answer has to be PREMIX or DIE.

RotaryEvolution

iTrader: (30)

i guess i just don't think i'm driving a ferrari to think it's embarrassing. aint no clunker either though, but i don't see eyes burning through me when i spend the 45 seconds to do it. can spend the timing filling several pre-measured bottles that fit easily into the filler from the security of your garage, another 20 seconds pouring it into the tank, other 25 seconds getting and putting the oil bottles away. sure it's a little bit of a hassle, but less of one pulling the engine out to rebuild it 10, 20, 50k miles earlier.

either way works but don't downplay effort levels here. you'll spend as much time and effort modifying the system at one time as others will spend over several fillups. several years down the road you may eventually be ahead of the curve. i'm also still not convinced that the OMP jet locations are optimal for lubrication points for universal lubrication, some years of testing would be involved.

although i don't think it's a horrible idea, i do in fact think it is a decent alternative if you can ramp up the OMP injection rate a bit at the same time. the stock injection rate is ok for moderate abuse, for those of us who abuse the car for longer periods of time the amount is inadequate.

Snowburn

iTrader: (2)

The Idemitsu pre-mix comes in a traditional quart sized bottle and is graduated on the side.
Add a clear flexible pour spot that can screw onto the top of the bottle and it's very simple to pour in a decently measured amount.

Black Knight RX7 FC3S

iTrader: (7)

I dont see the hassle of doing premix.
It only takes less then 20 secs for me before pouring the gas in. i dont even measure since Idemitsu is in quart size and the side of the bottle has level idicators in ounces stepping down 4 ounces every line. It doesnt need to be exact science.

I do agree that the stock nozzles are inadequate for abuse. Mazda designed the stock omp system for regular driving conditions. If you beat on your car regularly such as going to the track 4-5 times a month, or hard driving elsewhere, you are going to need to premix. The nozzle location from my opinion is not good enough of a location to lubricate even with a external premix bottle with the omp, especially for hard driving.

I drive my car hard, I know some only drive it moderately. if you dont want to inject engine oil into the housing, use the premix adapters if you hate to add it to the fuel yet would like to keep the omp. There is no perfect solution, theres downsides to every option, it all depends on you.

arghx

iTrader: (3)

The pores and channels are like a crosshatch. But better. If it were that easy, somebody would've done it by now.

R&D is expensive. If they wanted to save money, they wouldn't have bothered with R&D on the housings and instead kept the same design.

Mazda changed the coating a few times. Only the series 3 Rx-7 and later housings had the pores and channels I believe. They changed the rotor housing treatment multiple times... if they wanted to save money they wouldn't have paid engineers to research new types of coatings. They would have stuck with the one they adopted on the 10A, which sucked in comparison to what came on the FD and Rx-8 housings.

You should see the manufacturing processes that NSU was using in the 60s. They had all sorts of problems. If you want to learn more about any of this, you can send me a PM.

RotaryEvolution

iTrader: (30)

mazda obviously put a bit into the coating process, i can clearly see the graphite layers cut away on the series 5/6 housings when machining them. they are however usually through that layer in a few spots anyways.

of course that's also why i say pre-mixing is almost a pre-requisite when cutting the housings. i haven't seen Goopy mention it yet though but they should also warn their customers that the life of the later model housings is going to be compromised, considering they did last quite a bit longer before the step wear developed from the outside edges on those housings, consider it similar to the nitriting process they used on the irons. unfortunately i believe it has to be done at the same time as the coating process is done, so the housings can't be re-impregnated.

j9fd3s

iTrader: (3)

true. the pre74 engines always have great looking chrome when pulled apart, however the carbon seals they came with are really soft. if you put a harder iron seal on that same chrome it just gets torn up, its a no no.

Mazda upgraded the housings for the iron seals, and then again for the 12A turbo and GSL-SE, which gets the pinpoint chrome and a stronger steel insert, and then there are a couple of different coatings for the FC and then the FD/Rx8

notice Mazda's last update was to decrease friction?

j9fd3s

iTrader: (3)

actually since we're on the subject, the FD metering system WAS found to be inadequate. they have new oil injectors N3G1-16-631 (i think), and they redesigned the check valve in the rotor housing.

all the new FD rotor housings since 11/98 have the updated stuff.

bumpstart

/\ do you take us for idiots?

it was not inadequate oiling that forced the change

actually they wanted to keep selling the FD in markets where emissions required tightening
and so the grommet insert into housing oil injection well system mods allowed them to use in effect less oil for more lube when/where needed most while combating those emissions targets

i see the US didnt get the later specs FD's at all , so maybe that is the cause of ignorant or deliberately misleading statements like in the post above mine

----------

at the same time changes came for the faster ECU and the turbos became " abrasion honed "
and the engine output was lifted

and there is much litterature quoting the mazda man himself on the issue, here and all over the net

RotaryEvolution

iTrader: (30)

i'm sure there's other reasons but no need to get rude about it.. what would he have to really gain by saying that?

i'd probably guess we didn't get them because they were a high priced car that had known issues from the FC/FB/2/3/cosmo/REPU/etc generations and sales were falling, they do lose money shipping the cars half way around the world after all.

j9fd3s

iTrader: (3)

there is an SAE article on it. http://robrobinette.com/sae_article.htm

"Apex seal lubrication has become a critical issue. In a race engine, oil supply to the rotor housing by means of injection was precisely monitored and controlled, whereas in the production unit, a larger amount is supplied, just to be on the safe side. Some of the lubricant is fed into the trochoid chamber through a metering nozzle. The previous nozzle's oil passage was 2.0 mm (0.08 in.) in diameter. Negative pressure created in the rotor chamber would cause all the oil within the nozzle to be sucked out. When the engine accelerated rapidly, oil supply could not keep up with the speed. To prevent oil starvation, the previous system supplied a larger amount of oil to be on the safe side. In the new metering nozzle, the passage diameter has been reduced to 0.08 mm (0.003 in.), halving its volume of 0.0005 L (0.03 cu. in.). A new rubber seal is also inserted to fill a gap within the nozzle body where oil used to be sidetracked. Now, there is still some oil left within the nozzle after each suction, so that the lubrication system responds to the apex seal's requirement."

the word emissions is only used once "Would the faster RX-7 return to the American and European shores? Unlikely, as the car has been absent from these markets where emission standards have been tightened, and in its current state, could not hope to realistically achieve."

if you have some different technical info i'd like to see it.

Nataphen

iTrader: (6)

I hate to dig up an old thread, but this is something that I'm looking into. I was considering using the RA OMP adapter to run 2-stroke oil in that, plus run 1oz. of Idemitsu premix per gallon. I don't care about convenience, this is my fun car, I just want it to last as long and run as well as possible. Here's my plan so far, let me know if I'm way off base please.

-- 128:1 Idemitsu premix
-- RA OMP kit w/ 2-stroke oil
-- Idemitsu 20w-50 rotary synth in the crankcase

I realize I have an FD and this is the FC section, but I figured that pretty much the same rules would apply.

Level Zero Motorsports

iTrader: (8)

I'd premix at 100:1. You don't need extra oiling and the simpler your setup is, the less problems you will have with it.

j9fd3s

iTrader: (3)

Arghx found an SAE paper on oils in a rotary, and um the gist of it basically is that you should just skip the 2 stroke oil, and just buy the Idemitsu stuff.

they do explain the oil formulation you need for premix, but since the Idemitsu stuff isn't expensive, its not worth trying to hunt down something else.

Nataphen

iTrader: (6)

Would the 2-stroke oil not help clean carbon deposits? If I mix 100:1, will I need to remove the OMP? Thanks.

Black Knight RX7 FC3S

iTrader: (7)

I dont know about cleaning out the carbon with 2stroke (which I dont think it does), but at a 100:1 ratio, thats just a tab bit over 1 ounce to 1 gallon. With that ratio, you dont need the OMP to operate also.

epic

iTrader: (3)

I know there is a ratio for keeping the MOP and still premixing, not sure if it was brought up in the thread, but keeping the MOP to continue to pass oil into the engine and having the premix also to pass it along with the fuel. Again I am not sure on the Oz/Per gallon on that, but wouldn't that be a happy medium? Only asking because I have thought about doing this because I just recently replaced my MOP because the car went into "Limp" mode. I decided to replace it because at the time I wasn't sure how to block off the MOP and the ECU from reading it.

Black Knight RX7 FC3S

iTrader: (7)

going by half ounce to one gallon, its 64:1 if you are going to premix and use the OMP.

I was going to use both, use the OMP for regular driving, but only premixing with OMP at the track. Only problem I see with that is, if I was going to premix, might as well go all out and just only premix.