Return line clogged?

[turbojimmy]

Still trying to figure out why my brother's 87 T is smoking so bad. It's blowing oil out the exhaust elbow on the turbo and every crevice it could find.

We took the original turbo off. I've never seen anything like it. The shaft was moving around like there were no bearings or housing. Blades had dug into the housing long ago and the tips were all ground down and melted. Thought this was the problem.

Bought a used turbo from a board member. Said it didn't smoke but needed rebuilt. No big deal, we just want to get it running and maybe through inspection. Put it on, still LOTS of smoke. Smells like oil.

Figuring the condition of the used turbo we bought was optimisitically estimated by the seller, we put my PT-51 on the car. Same thing. Unbelievable amounts of smoke and oil. It's crazy. There's oil spattered all over the fender well and you can see it seeping out the elbow. When you shut it off you can hear it boiling (in the cat?).

All the plugs look good, runs fine otherwise. Compression is 150# +/- in all the cylinders.

Where could this oil be coming from? There's no way the engine could be ingesting this amount of oil and still be running.

My dad suggested that maybe the return is clogged? So the oil has nowhere to go but out the exhaust side of the turbo? Dunno.

TIA,
Jim

 

[darkred87T]

Could it be a bad PVC?

 

[turbojimmy]

Clarification: the smoke is out the tailpipes. Tons of oil getting dumped into the exhaust - at or after the turbo. Even with a known good turbo on it.

My turbo doesn't have an inlet bell so we left the breather hanging. The crankcase is not pressurized, so it's not an engine thing. Something to do with the turbo and/or oiling system.


Thanks,
Jim

 

[petesgn]

Maybe i takes a while to burn oil out of the exhaust system ?

 

[darkred87T]

That's what I thought at first until it warmed up and really started billiowing out the tail pipes again. Also, smoke is still comming out around the turbo. If it was just burning what's left in the exhaust, it would not be forcing it's way out of the turbo.
I'm going to try replacing the PVC. (It's a cheap way to find out if that's the problem or not). If the crank case isn't ventilating properly, wouldn't the build up in pressure not allow the return line to let oil back into the engine?

 

[turbojimmy]

Originally posted by darkred87T
That's what I thought at first until it warmed up and really started billiowing out the tail pipes again. Also, smoke is still comming out around the turbo. If it was just burning what's left in the exhaust, it would not be forcing it's way out of the turbo.
I'm going to try replacing the PVC. (It's a cheap way to find out if that's the problem or not). If the crank case isn't ventilating properly, wouldn't the build up in pressure not allow the return line to let oil back into the engine?

They're independent systems. The pressure of the oil feed into the turbo is from the oil pump. Any pressure in the crankcase would be from compression (blow-by). Since you put my PT51 on it, you've eliminated the vent from the valve cover (no inlet bell vent) and left that tube hanging. If there were crankcase pressure it would come out that tube. There isn't any. Plus, if it were crankcase pressure, it would be drawing that oil into the combustion chamber. There's no way the car would run with that much oil in the combustion chamber. The car runs too well for it to be a combustion thing.

I'm not 100% convinced that what you're seeing isn't just A LOT of oil in the exhaust system burning off. It gets worse when you rev it up, but things also heat up when you do that.

BTW - Darkred87t is my brother........it's easier to communicate this way sometimes

Jim

 

[turbojimmy]

Could we run the car with the DP unhooked at the elbow to determine whether the smoke is coming from the engine/turbo or the oil-filled exhaust? Other than the noise, is there any danger in doing that? Or should we hack off the exhaust in front of the cat? The cat is likely filled with oil and probably no good anyway.

PS - despite the subject line, we found that the return line is NOT clogged so it's something else.

Thanks,
Jim

 

[petesgn]

Like you said start it without the down pipe at the turbo and see if it smokes then.

Shouldn't be any problem just slight noise

 

[turbojimmy]

Originally posted by petesgn
Like you said start it without the down pipe at the turbo and see if it smokes then.

Shouldn't be any problem just slight noise

So my brother unhooked the DP at the elbow and ran it. Squeaky clean. Hooked it back up and started it - tons of smoke. I told him to go out and romp on it to try to clear it out.

His house is on the way home from work. About 1/4 mile away from the house I noticed a fog had set in. It was unbelievable. The car had literally caused a fog condition with oil smoke over about a 1/2 square mile area. You couldn't even see the driveway.

I think it's starting to clear up now - but it still smokes a lot. It's gotta all be in the cat and mufflers. The cat has gotta be toast so I think he's just gonna hack it off from the DP back.

Thanks for the replies.

Jim

 

[TurboJim]

Jim, did you pour oil down the return line to verify it flows? Its possible that there is coked oil schmeg in the intake valley that could be restricting drain flow

To make that much smoke, the plugs would haveta be really ****ted up. Since they're not, the oil has to be coming POST engine.

 

[turbojimmy]

Originally posted by TurboJim
Jim, did you pour oil down the return line to verify it flows? Its possible that there is coked oil schmeg in the intake valley that could be restricting drain flow

To make that much smoke, the plugs would haveta be really ****ted up. Since they're not, the oil has to be coming POST engine.

Yeah, we poured oil down the drain - it sucked it down no problem. Plugs are good, and the car makes really decent power - just lots of smoke. It's actually starting to clear up a little. It needs run a bit more to clean itself out. That turbo was the worst I've ever seen. There's no way it was even turning anymore. Oil was basically getting pumped directly into the downpipe for gawd knows how long.

I think this car holds some promise.......

Thanks,
Jim

 

[Chuck Leeper]

Cat trashed!!

You can bet the cat is history w/ that much oil going into the brick..I wouldn't try to pass emissions w/ it!!
Also, it may have some serious backpressure as the core holes can be plugged w/ crusty oil deposits...

 

[turbojimmy]

Re: Cat trashed!!

Originally posted by Chuck Leeper
You can bet the cat is history w/ that much oil going into the brick..I wouldn't try to pass emissions w/ it!!
Also, it may have some serious backpressure as the core holes can be plugged w/ crusty oil deposits...

No doubt. I think you're right about the back pressure. The more we run it the worse it runs. But if you unhook the DP at the elbow it runs awesome. I'll have to hack that cat off today. You think the mufflers could have filled with oil, too? Hopefully I can get away with just putting a test pipe on it for now (as in hopefully the mufflers and rest of the exhaust system aren't totally full of oil, too.

Thanks,
Jim

 

[Chuck Leeper]

Oily "muff"??

I'd take a look at the system when you get the cat off, and go from there w/ the muffs, etc..
usually, if the sytem is not welded on, there will be some oily crap blown out of the joints at the muffs if they are REALLY bad...

 

[turbojimmy]

Re: Oily "muff"??

Originally posted by Chuck Leeper
I'd take a look at the system when you get the cat off, and go from there w/ the muffs, etc..
usually, if the sytem is not welded on, there will be some oily crap blown out of the joints at the muffs if they are REALLY bad...

I dunno how long this guy was driving it like this, but there is enough oil in the exhaust system to come out the tail pipes as late as yesterday. I think it's mostly out now, but thatsalotta oil. I'm going to donate my gutted cat to the cause - he's going to have to find an adapter to go from the DP to the 3-inch "cat". That'll give us time to drive it around without drawing too much attention to ourselves. If it runs good (trans was whining last night) we'll title it and get tags. If not, look for some T parts soon

Jim

 

[darkred87T]

In traditional Thanksgiving Day fashion, my brother did some wrenching on the '87 T. Remember that we've had 2 different turbos on this thing and it's smokes like a chimney at idle and any other RPM. It's an unbelievable smoke screen that fogs up the 'hood.

Pulled the cat today and put a test pipe in its place. Runs clean as a whistle. If I didn't see it with my own eyes I'd never have believed that residual oil in the cat would have caused that much smoke for such a long period of time.

But, it's fixed. Runs great and looks to be a good foundation to work from.

Jim (using my brother's ID)

 

[petesgn]

Good to hear

 

[turbojimmy]

Originally posted by petesgn
Good to hear

Thanks. I think I'm more psyched about this car than my brother is. It's like starting all over again but this time I have 5 years of tinkering with my GN behind me.

Next step is a good title and tags so we can get it on the road.

Jim