nodestination1

iTrader: (2)

Ok, here's the deal. 1987 TII with a hybrid turbo, No OMP and running premix. The car ran fine last year, no smoke.
I parked it over the winter with a full tank, including 1oz of premix per gallon, maybe a bit more. I also put some stabil in there.

Over the winter I pulled the turbo apart and enlarged the wastegate flap. I was very careful with my grinding and welding, making sure I didn't get shavings all over. That was just the exhaust housing though, I didn't really touch the CHRA.

I started the car after letting it sit for 6-8 months, and it started smoking like a mother. There is a black, liquidy, nasty substance pooling up in the exhaust and leaking from the exhaust flange. It seems too thin to be motor oil.

I ran the car up and down the block and took it for a quick trip downtown. It was blowing so much smoke people were running outside because they thought something was on fire. No joke. Driving the car didn't seem to clear it up, so I shut it down and put it back in the garage.

I'm not sure if a.) The turbo is leaking oil, or maybe coolant, into the exhaust
or b.) All the premix settled at the bottom of the gas tank, and the pump is picking up like 100% 2 cycle oil. I figured tossing it around some corners would mix up the tank though?

Any thoughts are appreciated. Im considering draining the tank first, then trying a used H-18 on it to see if that fixes it.




What is this!?!

lduley

iTrader: (1)

I highly doubt that its the premix in your tank, because a good percentage of it should be burned off before it hits the exhaust. Also, if it was running only on 2 stroke, it wouldn't run worth a crap or not at all

check your plugs, if they are nasty, than probably oil control rings, if they are clean as a whistle, turbo is probably got a blown seal. Hows your TB look?

fc323

Fuel goes bad really easily since its so refined. Unless you put a fuel stabilizer in the tank, I would think its the fuel being weird. Never had a tank with premix sitting for that long, but I would think its the black gunk

LargeOrangeFont

iTrader: (7)

It's not the fuel going bad, you are getting oil in the exhaust. The turbo is probably toast. As stated above, check the plugs.

misterstyx69

iTrader: (142)

ya X2
that is oil so it doesn't have anything to do with fuel delivery or your premix.

re-rx7

iTrader: (3)

x2.

fc323

Whelp, I learned my lesson. :p

philiptompkins

iTrader: (4)

And yea, 2 stroke does settle to the bottom of the tank. I think this would only be an issue for me first few minutes though because a combination of driving and the fuel pump running would quickly mix it up.
Also 1oz per gallon is a little on the heavy side. That's like 64:1.
Id try topping it off with fresh gas and changing the spark plugs before tearing into the motor.

Edit: I just read the above posts and agree. If oil is seeping out from behind the turbo it's probably time for a turbo rebuild.
At least you found your exhaust leak!

cone_crushr

iTrader: (18)

^Please ignore the previous post. Among other things, 1 gal = 128 oz. And while it can, typically premix doesn't settle to the bottom of the tank since the oil is in solution.

nodestination1

iTrader: (2)

Thanks for the info guys - I will rule out the gas/premix as a possible cause, though I will probably drain some of the tank and mix in some fresh gas just to be sure.

I'm leaning towards this being a coolant issue. It doesn't have the feel or consistency of oil. I think the coolant is mixing with all the carbony build-up in the exhaust to make it like a black watery substance. The smoke also seemed more like coolant - oil burning has a very distinct smell.

You're right, I should check the plugs and combustion chamber. That will help tell me if it's the motor or the turbo causing the trouble. I was in the process of moving at the time so I didn't really have time to dig into it.

re-rx7

iTrader: (3)

1oz per gallon is the way.

misterstyx69

iTrader: (142)

Sorry Phil if a gallon is 64 oz in the US then that would be correct.(64:1)
1 to 1:it works out to 128 oz in a gallon to one ounce of two stroke.
64:1 would be TWO ounces of 2 stroke in one gallon of gas(excessive premixing),and that would most likely bare it's head as plug fouling.

If the OP wants to see Oil smoke then look at the NEW tech section and see my Dyno run.It blows smoke on De-cel.
That was a bad seal.The turbo got rebuilt after that Dyno run.
LINK:https://www.rx7club.com/new-member-r...haust-1069247/

misterstyx69

iTrader: (142)

It doesn't take much to mix the gas and oil in the tank.A little sloshing and it is good to go.Usually if you put the oil in and then the gas it is mixed by the time you put the nozzle back into the gas pump.

nodestination1

iTrader: (2)

Thanks for posting that video link. Yeah, I don't think it's leaking oil from the turbo. I think it's coolant.