a friend of mine just bought a T2 today. the guy he got it from isnt all there, kinda slow, but the car was in decent shape for only costing 750 bucks. but the one nagging question in my head about the car is why does it smoke so much? it smokes on startup, but after the car heats up to operation temp, it disapears. the guy at first said it was because the car has been sitting for so long. the smoke is grey-blue and reeks of oil. well my friend and i drove the car and it smokes when under boost as well. when i asked the owner about that, he told me it must be becase of the 2 cycle premix he put in it. i can kinda believe that, but im still not too sure. any other reason it would smoke like that. only on startup and under boost. is it the premix, turbo seals, or a bigger problem?

 

Could be lots of things. Premix, oil control rings, turbo on its way out. I wouldn't worry too much to be honest.

 

Well I and at least 3 guys in the Tampa area premiix that I am positive about and nobody has smoking problems. So I don't believe that premixing is the cause of the smoke. 2 stroke oil smells a lot different than motor oil when burning btw.

 

You never know how much and of what exactly a "kinda slow" guy will put in though, ya know? My guess is turbo going bad, but who really knows online.

 

first things to do is get a used car inspection from a rotary mechanic, it could be many things but a TII for 750 is a steal, replace oil injector lines and the turbo oil lines, there is no need to premix if the the stock oil injection is working properly...................

 

Pre-mix would not cause a smoking problem. Especially if it goes away after you reach operating temp. Check turbo for oil leaks, or you possibly bad oil seals.

 

even if it is the oil seals you can pick a jspeck TII engine up for under 1000 US, I sugest you do that, damn I wish my seller was that incompetenet!

 

Have you torn down a rotary engine and witnessed the carbon-caking side-effect of injecting relatively heavy, dirty crankcase oil into a combustion chamber? Those of us who premix and remove the OMP do it to avoid this effect. Acids, blow-by and dirt are all present in the crankcase oil in small quantities unless it was just changed 5 miles ago . . . which bakes onto the rotors, ports, and apex & side seal slots. One contributor to low compression in rotaries is apex seal slots which have crud on and in them. This prevents compression pressure from efficiently forming under the seal which presses it against the housing . . . It is also a mild first step toward having a carbon locked engine where the deposits get so bad that seals are prevented from moving freely at all.

And besides, deposits can lead to preignition and detonation when they get really thick and nasty!

But there are many, many reliable NA engines with stock oil injection so it can't be too harsh. I am just a clean freak I guess

 

well premix reduces's octane which cause detination, and i have seen rotor housing using the stock oil injection......you just have to have it calobrated correctly, mazda use that for simpicity..........

 

The ratio of premix is 150:1 to 200:1 and lowers the octane by a fraction (less than half) of a point. Housings do not build up the crud because they have apex seals scraping them continuously. The rotors get the carbon coating . . .

 

Dont use premix if you REALLY want your rotors to end up looking like this:

 

Yeah, god forbid it look like a rotor showing perfectly normal wear...

 

Sounds like a carbon seal on the turbo

Oil drips after you turn off the car for a while and smokes when you crank it up and then goas away till you hit it hard

Bad O-oil seals would smoke at all RPM's

 

when a car has bad oil control rings, it will smoke at high RPMs. I would try putting thicker 20w50 oil in it, and run the tank to E and re fill it with the correct amount of 2 stroke oil

 

The high spot on that rotor destroyed a housing that had about 100k miles on it....

 

well the only reason i think the smoke might be from the premix is because the stock oil metering system is still there. i figure if there is extra oil present in the fuel, then when its added to the oil already being injected into the motor, it might cause smoke at some times. i wouldnt put the turbo out of the question though, that could very well be the problem.

 

I dont believe that would be enough oil to make the exhaust smell like it is constantly burning oil or make it visible. Run the gas out of it, then fill the tank up and run it out again. It should mostly clean any premix out of the tank. But ugh, it sounds like the turbo is on its way out.

 

Yeah, he'd have to put a shitload of premix in there for it to cause smoke. I run with about 13 oz of premix per tank in addition to the OMP (so I'm burning about twice as much oil as I normally would) and my 7 doesn't smoke at all.

Although the exhaust is LETHAL.

 

lol. Fumes from a rx7 can kill

 

dont i know it. my T2 runs rich as all hell thenks to a pair of untuned 720s. i can only stand behind my car when its running for a few minutes before i need to come up for air. heh.

 

Premix is not the cause of the smoking, the oil seals on the turbo are going, do you have any shaft play? Not that is matters it smokes alot right? Its either engine seals or turbo seals.

I run heavy premix and OMP, my engine has over 300,000, and smokes heavy after a 7000 plus RPM run, but only for maybe 5 seconds..Smoking isn't a bad thing always.. if the car is fast and runs good, **** it and smoke out...

 

Yeah, chicks dig smoke.

 

High spot?

 

That high spot he means is the one created by running the OMP. The center section of the apex seal section, that what he means by high spot.. If he really used premix the whole time, the rotor would not have those low spots/ high spot across the apex seal...It would have uniform wear, and less of it....

 

Does anyone know if there is a way to inject 2-stroke synthetic oil through the oil lines? It seems to me that this would be a better way to go than premixing the oil with the gas. I know that an oil tank would have to be installed, but it wouldn't have to be that large. Motorcycle manufacturers have done this since the '70s.