Oil in Exhaust system

[Pautpadoo]

Greetings All,

I recently got my 84 911 Targa running after 10 years. I had sprayed a little fogging oil in the cylinders and turned it over by hand over the years. But it seems that the oil in the cylinders is motor oil not fogging oil. The plugs were oil fouled and I replaced them to get it started.
Now that it is started I can barely run it for more than 10 seconds as it makes a HUGE cloud of smoke..preventing me from running it long enough to determine what condition the motor is in.
It appears the exhaust system has oil in it. Oil was dripping from the joint between the heat exchangers and the CAT. One of my mechanic freinds recommended that I replace the CAT with a by pass pipe and replace the muffler as running it hot would never burn out the oil soaked metal.
Replacing those parts would be somewhat expensive, so to save the $ I thought (hope) removing and seperating the components of the exhaust system and degreasing them some how may work.
I suspect this is not a unique situation and would greatly appreciate some sage advice from someone who has been there.

Thanks much,

Mark

[Ngrich99]

My '79 sat for eight years before I found it. I did all the things and when it came time to start it smoked so much I turned it off. Pushed it out of the garage, started it again and let it run. It cleared up eventually.y and has been a smoke free solid driver for the last two years. I'd wait til it's dark and go give it a drive.

[faapgar]

Hi,a few years ago I bought a Carrera 3.0 that had sat for around 12 years.When I fired it up it smoked for about 45 minutes then cleaned up.My neighbor called the fire company thinking the garage was on fire the smoke was so thick.When a 911 sits for a while all the oil seeks its own level.Fills the crankcase & bleeds past the rings & guides.Leakdown before it ran was 80%.After it ran for an hour it was 4-6% and no smoke.Fred

[911pcars]

If not accumulated oil from the engine sitting in storage, it's usually due to piston rings that might be worn and/or stuck in their grooves preventing adequate cyl. wall wiping. Some ATF or Marvel Mystery Oil added to the crankcase and driving it to full operating temp. might allow the rings to work as designed. It could also be worn valve guides.

Perform a compression test with and without a squirt of oil to help confirm/isolate the cause.

Sherwood

[Trackrash]

I agree, it will burn off after awhile. However, I would be concerned that the cat might be permanently damaged. I would put on a cat bypass before running it again.

[Pautpadoo]

Hi fellas

I think I'm hearing a similar opinion that a 911 that sits for a while will seep oil past the guides and rings and through open exhaust valves to enter the exhaust manifold and as far as the CAT.
But can the oil get into and past the CAT to enter the muffler? It is legal in my state to remove the CAT on a car of this vintage and a bypass pipe might improve the performance?
It appears that burn offs have been eventually successfull by many of you too. Comforting to hear, as I hoped not to have to remove the manifold and heat exchangers and risk breaking a stud, or the expense of a new system and muffler.

I should be able to get the car to a open field or a dark breesy night to let it run long enough to burn off at least long enough that I'll be able to see the car when it's running.
Last time it was running there were no reported issues with the rings or valve guides.

Thanks so much for all the advice. I am so appreciative and impressed by the people on this site...such a willingness to help. It's a great connection

[rwest]

Had a similar issue; car sat for a year and a half while I redid the suspension and when I finally got it back on the road the smoke was awful- cleared up after some driving, somewhat embarrassing driving!

[BeeMaster]

Yep when I got my car it had sat for many years. When we got it running it smoked a lot so I took the muffler and exhaust off and the mufflerhad a bunch of oil in it that had to be burned off. Started it with no exhaust at all for about 5-10 seconds and no smoke from the engine. OMG WAS IT LOUD!

[T77911S]

oil drains from the tank into the engine. that is a lot of oil.
it will seep past the rings.
I would be careful of hydro lock from this. could be very damaging.

best thing is to drive it and see if it gets better.

[theiceman]

Originally Posted by Pautpadoo

Hi fellas

I think I'm hearing a similar opinion that a 911 that sits for a while will seep oil past the guides and rings and through open exhaust valves to enter the exhaust manifold and as far as the CAT.
But can the oil get into and past the CAT to enter the muffler? It is legal in my state to remove the CAT on a car of this vintage and a bypass pipe might improve the performance?
It appears that burn offs have been eventually successfull by many of you too. Comforting to hear, as I hoped not to have to remove the manifold and heat exchangers and risk breaking a stud, or the expense of a new system and muffler.

I should be able to get the car to a open field or a dark breesy night to let it run long enough to burn off at least long enough that I'll be able to see the car when it's running.
Last time it was running there were no reported issues with the rings or valve guides.

Thanks so much for all the advice. I am so appreciative and impressed by the people on this site...such a willingness to help. It's a great connection

I seriously doubt it is legal to remove a factory installed cat in any state these days. More likely they don't check after certain years in your state.

[Joe Bob]

Drive it at night until it goes away....

[RSTarga]

Pull the plugs and turn over to make sure you don't bend a rod trying to compress oil. Then drive till it burns off. If it got into the cat you'll have to replace it.

[JohnJL]

Italian tuneup, once you check no vacuum leaks and everything else is OK.

I didnt notice you say you did an oil change? Condensation from ambient air over the years can leave some water in the case, give her fresh oil too.

[911nut]

Oil won't soak into metal. It just lays on the surface.
If the cam cover gaskets are shot, oil will drip onto your cat and into the heat exchangers.
You should follow the advice here: run the car and drive the car long enough to heat everything up. You won't hurt anything.
I would add that you should clean off the oil with brake cleaner and a rag so that you can track any oil leaks after you drive it.

[911pcars]

I could be wrong, but I suspect circulating liquid engine oil through the oven-like catalytic converter might choke the passages with carbon and render it useless as well as creating a significant restriction. Refer to the appearance of spark plugs subject to excess oil.

Instead, remove it and substitute a cat bypass tube for the "blow-out" procedure, then figure out how to remove existing oil (or carbon) from the cat. Anyone ever done that? Thoughts?

Sherwood

PS: Article re: cat passage size
http://www.carexhaustreviews.com/what-does-exhaust-catalytic-converter-cpsi-stand-for/