Vell

Hi,

Question :

My engine failed after ~7 hours running. I run without the OMP (premix 3%).

I was wondering if a big amount of oil in the combustion chamber can cause an apex seal failure ? (like auto ignition)

Maybe it's a silly question but ... to be honest I don't understand why this engine failed so quickly.

I was losing some power after 1 WOT lap, a lot of power, like there was too much oil in the combustion chamber. My oil smells fuel ... a lot ! And I know, 3% premix is a bit too much, but it was for the first days ...

First, I thought something passes through the air filter (they aren't in great condition)
Second, I thought about a boost pike (no datalogit this day !!!).
Now, I don't know.

Here are some pictures ...
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Any input will be greatly appreciated... Thanks

Nick_d_TII

iTrader: (6)

That sux.

Just a guess, but the oil control ring springs have little tabs on them and they may have not been put in correctly?..? I don't know...

Open it up...

Wargasm

I would think that excessive oil would cause ignition failure, not detonation.

The oil smelling heavily like gasoline is a clue that the oil control rings were not sealing or that an injector was stuck open or something like that - dumping a ton of fuel in the engine.

Those apex seals look pretty trashed - definitely some detonation I think.

You said that the car ran 7 hours - but lost power after one WOT lap on the track. Did you break it in on the street first? How did it drive at that time?

Please tear it down and let us know what you find, I am interested to know what may have caused this.

Thanks,
B

Sandrock

iTrader: (26)

Yeah did you have a proper break-in time on the engine,.. ? Also,. I have the RA OMP conversion,. and dump strait 2 stroke into my engine, like lots of it, my car smokes like a mad beast when I sit around and idle,. but no carbon buildup, anti-friction and anti-scuff.

GoodfellaFD3S

iTrader: (213)

When you say 3% premix, what ratio are you running?

Vell

Hi,

The car ran an entire track day, mostly in the pits @ idling unfortunately ... ^^
This day (not the D-Day) the car made a lot of laps with less than 7 psi boost. Pushing it gently as the engine was not brand new but sitting in the garage for ~1 year.

The D-Day I've warmed up the car as usual, 4 / 5 laps without pushing hard, looking for the AFRs, looking for boost spikes in the last lap ... Then, I came back at pits, let the car at idle when I was looking for something weird.
As everything was ok, the car was hot, I made another warm up lap and then a drift lap @ WOT, hitting the REV limiter 2 or 3 times (I know, it's bad as it's the PFC limiter @ 8000 rpm).

Then, the car started to run like the engine was fooled by the gas. Ok, cooling down lap, as I wanted to go back in pits.
During this cooling lap, I was trying to clean the plugs and to avoid stalling by reving to 4 / 5 k rpm in neutral.

Then, when I was hitting the ~4K rpm mark, I suddently lost a rotor, the can has barely ran to the pits.


My premix was at 3 percent so for 60L I've added 1.8L (Good old liters :P)


I am aware about ignition breakup, but I've heard some stories about an excess of unburnt fuel causing an "uncontrolled" ignition, doing the same damages as detonation ... ?


PS : I'm sorry for my poor english ... !

Nismo Convert86

iTrader: (7)

Thats a hell of a lot of premix... That actually could effect octane ratings. I usually added 500-600mL to 50liters.

g14novak

iTrader: (1)

Going to the limiter on a fresh engine is very hard on it.

Another note is that the PFC's limiter is a fuel cut, not a ignition cut.


Had the engine been run at all before you installed in the car for the ~7 hours? Or was it just assembled and let to sit?

Vell

I may have explained it the wrong way ^^

This is a second hand engine, a well know rotary specialist said it was a good engine. I've bought it, then left sitting in the garage for a year. I've oiled and turner the engine during this year.

Then, put it in my car, ran gently for several hours, and then pushed hard for my second track day with 0.9 bar (which is near 13psi if I'm not wrong).


But the engine has lost the apex during the cooling lap, neutral, tiping the throttle to avoid flooding.

Nismo : I don't have any OMP

Nismo Convert86

iTrader: (7)

Yeah I got that, I ran 5-600mL with no OMP. I run 200mL on my car with a functioning OMP. almost a half gallon of premix in the tank is excessive, new engine or old.

imitek

hear m8 what happend to this

ppre

Have you pulled this engine down yet?

RotaryEvolution

iTrader: (30)

doubt it died due to too much oil but it will affect octane rating, but it shouldn't that much at only 13psi.

until you tear apart the motor, i would assume the irons got scored and leaked the oil into the chamber AFTER the engine was already done. if it ate an oil seal on the track it would be smoking excessively and not lose much power at all. oil seals usually don't go in just one day either(i have never seen it).

Vell

Hi,

As I moved in a new house recently, I will be able to tear it down soon and eventually figure out what happened that day !

Karack, I think the oil seal was leaking since a long time, the car was smoking but I was thinking about my premix when I was on track.
I hope that the parts will reveal the truth.

Vell

Finally ...

Vell

D Walker

iTrader: (1)

Interesting.
Couple of things spring to mind-

If you are over-premixing you will effect the octane rating of the fuel and this *could* lead to a detonation issue, although doubtful at only 13psi.
It really looks more to me like FOD damage from the engine inhaling something. Is the damage on one rotor only or both?

Couple of questions as well-
What apex seals are those? Look like OEM Mazda but hard to tell really
What fuel were you running at the time?
Obviously it has been awhile, but do you remember your coolant temp range for that lap or set of laps?

peejay

Are the corner seals stuck because the rotor tips are crushing them, or do they move freely?

Vell

The corner seals are all ok, 1 or 2 are stuck because of the apex / side partially destroyed.

D Walker, that's the problem, you are pointing it. This day, I wasn't reading anything, I was blind without my computer, and my cluster gauge ain't shown anything.

My dad thinks it's due to overheat. My thoughts are gonnay follow his.

The fuel is like your 93, it's called super 98 here. The seals are all Mazda OEM I think, but I'm not sure, it's a second hand engine ...

The front rotor has only one scratch near the exhaust port (before the port, middle of the rotor track). Everything else is fine, but I've noticed two colored circles on the e shaft which leads to the overheat too.

Maybe this + too much oil = mega disaster ?


Anyway, I know that I was just stupid to run the car like this. I will rebuild another engine that I got as spare. I made some big mistakes and I am learning about it ... ! It's the truth, those engines don't like idiots

RotaryEvolution

iTrader: (30)

if the engine was running that hot it is very possible it just auto detonated because the internal combustion temps rose to the point that the fuel auto detonated. you really should install an aftermarket temp gauge, even the stock gauge is a dummy gauge and not reliable for racing applications.

Vell

Thanks for the input!
I should have done a lot of things before getting the car on track to be honest ... I've been dumb.
Now I'm getting everything needed, don't worry !

Vell

Hi guys, it has been a while ...

Today I just looked at my LIM and may have found the culprit ...



Any thoughts?

RotaryEvolution

iTrader: (30)

quite possible, the rotor side seals are also made of cast iron and are very fragile so even a piece of plastic can take one out. a side seal failure would explain the excessive oil, because the side seals get drug around between the rotor and iron which cause gashes in the iron for oil to get past the oil control seals.

anything entering the ports usually is sheared by the rotor passing over the port, the pieces of atomizer could have cracked the side seal and caused the above.

did any pieces of the side seals go missing during the carnage? usually detonation damage won't touch them and just explodes the apex seals. if the bits of plastic did make it into the motor without fracturing a side seal then i really doubt it could be the reason the apex seals got taken out. the apex seals can take a little more abuse than a tap from an atomizer grenading inside.

Vell

Not exactly missing... but a big scare :

RotaryEvolution

iTrader: (30)

looks like a small piece of apex seal went through. i'd check the injectors to have them flow tested as i don't think you've found the problem just yet.