• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Tailpipe always smoking...

T

turbojose

Active member
Joined
Feb 22, 2009
Location
SF bay area
My tailpipe is always smoking and i'm finally tired of it. I have always just ignored it because its a 40 year old volvo. but today i have had enough. Some back story, i have a built 2.5 liter with only about 2000 miles on it. and It's a turbo car with a garette gtx3076bb turbo. this is with a 16v head and a 90+ manifold and 3" exhaust.

list of the important modifications:
1.) 16v head
2.) 2.5 stroker crank
3.) newly rebuilt bottom end (abot 2000 miles)
4.) head was rebuilt about 5000 miles ago.
6.) I run an oil restrictor for the turbo .035
7.) I also have turbo accusump booster accumulator

Some thoughts and things i have tried.

I run my crank case and valve cover gases to a catch can vented to the air with a combination of vacuum being pulled to pre turbo intake.
*I have been through three turbos thinking it was the cheap ebay turbos i was running but each time the same result... it still smokes. and the last turbo i purchased was directly from garrets not a cheap imitation, and still the same result.

I thought it may be my turbo drain back, but it is almost vertical, and -10AN line and fitings and flows great. non the less i have tried different hose and diferent fittings and still the same results.

the last set of plugs i pulled had oil on plug 3 and 4, so i was thinking i may have a ring issue. I ran a leak down test today, and the result were
#1 3% loss
#2 2% loss
#3 2% loss
#4 2% loss

so i was left stumped. the rings appear to be good, and no or gasket or valve issues.

I'm thinking it may be leaky valve stem seals, but not sure how to test for that.

and it makes me wonder if the head has valve stem seal issues, has that been ever since i hade the head professionally rebuilt?

any way long story short, i'm at a loss, and I just want to drive a volvo that doesn't stink up the road like uncle bucks 1980,s station wagon.

any one have any ideas they want to share?
 
In my (somewhat limited) experience, if there’s oil leaking past the valve steam seals, it shows up as smoke only in specific conditions like startup or when accelerating after idling for a while.

Is the smoke you’re seeing constant or only happening sometimes?
 
andyb5 said:
In my (somewhat limited) experience, if there’s oil leaking past the valve steam seals, it shows up as smoke only in specific conditions like startup or when accelerating after idling for a while.

Is the smoke you’re seeing constant or only happening sometimes?
Click to expand...
The smoke is intermittent. Like it’s always at startup. Then after hard acceleration definitely. But only sometimes at idle.
 
ZVOLV said:
Pull the downpipe and inspect for an oily turbine housing.
Click to expand...
I can pull the down pipe and snap a pic later tonight. Can you help me with understanding the wet turbine? If it’s wet does that mean the TiVo is leaking or is it something else? I wonder only because I imagine it’s definitely wet. But I will post later. Thank you so much for your input ZVolv.
 
turbojose said:
I run my crank case and valve cover gases to a catch can vented to the air with a combination of vacuum being pulled to pre turbo intake.
Click to expand...
Can you explain the plumbing a little more - what do you mean by vented to the air, and combination of vacuum?

Do you see much oil in the catch can, and catch can hoses?

Can you temporarily remove/disable the "turbo accusump booster accumulator" and see if it makes a difference? I'm not sure what happens if you spin down a turbo while still applying full oil pressure - can this pump oil past the bearing once the turbo stops spinning?
 
If the turbine is soaked black with oil, I would say the dynamic seal is the turbo is blown.

When I go pull junkyard turbos, I make sure the turbine isn't oily. If it is, I don't buy the turbo.

You can always pull the 02 sensor and borescope the turbo. It might be easier, depending on your setup.
 
bobxyz said:
Can you explain the plumbing a little more - what do you mean by vented to the air, and combination of vacuum?

Do you see much oil in the catch can, and catch can hoses?

Can you temporarily remove/disable the "turbo accusump booster accumulator" and see if it makes a difference? I'm not sure what happens if you spin down a turbo while still applying full oil pressure - can this pump oil past the bearing once the turbo stops spinning?
Click to expand...
-Can you explain the plumbing a little more - what do you mean by vented to the air, and combination of vacuum?
I run a -12an hose from the Volvo separator box to a catch can/breather box, and another -10AN from the cam cover to the same breather box. and that breather box has a filter to atmosphere. attaching a picture here.


Untitled by turbojose, on Flickr



-Do you see much oil in the catch can, and catch can hoses?
There is very little oil or residue inside the catch can box.

occasionally, i will tie in a -10an hose from the breather box to the pre-turbo tube... this helps keep the stink down when daily driving it. but I have not seen any oil inside the pre-turbo tube or intercooler. I took the intercooler off last week and let it drain on its side for 30 minutes, and not a drop of oil came out. its pretty dry inside the intercooler and intake tubes.

Untitled by turbojose, on Flickr


I can shut off the accusump accumulator... it has a ball valve. this is a faily new add though. it has smoked way before the addition. I see how this can complicate things though, so i will shut it off for a few days and let you know how its affected.
 
Last edited:
ZVOLV said:
If the turbine is soaked black with oil, I would say the dynamic seal is the turbo is blown.

When I go pull junkyard turbos, I make sure the turbine isn't oily. If it is, I don't buy the turbo.

You can always pull the 02 sensor and borescope the turbo. It might be easier, depending on your setup.
Click to expand...
good info... I'm pulling the down pipe now so I can get a good picture of the turbine.
 
"The smoke is intermittent. Like it’s always at startup. Then after hard acceleration definitely. But only sometimes at idle."
"There is very little oil or residue inside the catch can box."
"The last set of plugs i pulled had oil on plug 3 and 4, so i was thinking i may have a ring issue. I ran a leak down test today, and the result were
#1 3% loss
#2 2% loss
#3 2% loss
#4 2% loss"
Do you have the numbers for dry&wet compression tests? All good?

Sure seems like it's pointing to bad valve stem seals. Normally, only the intake valves have seals because only the intake valves are subjected to vacuum that can pull oil past the seal into the combustion chamber. Exhaust valves are mostly under positive pressure.

Intake vacuum is highest on hard decel, and high at idle. Plus there can be some leakage when the engine is stopped with a pool of oil in the head above the valve.

I don't know if there's a simple test for stem seal leakage? Maybe do a leakdown test but crank it around until intake valve is open and block off the throttle body + hoses and listen for a hiss under the oil filler cap?
 
bobxyz said:
"The smoke is intermittent. Like it’s always at startup. Then after hard acceleration definitely. But only sometimes at idle."
"There is very little oil or residue inside the catch can box."
"The last set of plugs i pulled had oil on plug 3 and 4, so i was thinking i may have a ring issue. I ran a leak down test today, and the result were
#1 3% loss
#2 2% loss
#3 2% loss
#4 2% loss"
Do you have the numbers for dry&wet compression tests? All good?

Sure seems like it's pointing to bad valve stem seals. Normally, only the intake valves have seals because only the intake valves are subjected to vacuum that can pull oil past the seal into the combustion chamber. Exhaust valves are mostly under positive pressure.

Intake vacuum is highest on hard decel, and high at idle. Plus there can be some leakage when the engine is stopped with a pool of oil in the head above the valve.

I don't know if there's a simple test for stem seal leakage? Maybe do a leakdown test but crank it around until intake valve is open and block off the throttle body + hoses and listen for a hiss under the oil filler cap?
Click to expand...
Thank you for the input... i always wondered about the resting oil in a slanted motor like this. I think it's time to pull open the cam cover and check a replace the valve stem seals at this point.

Do you have the numbers for dry&wet compression tests? All good?
I did do a compression test before the leak down, and the numbers were
#1 172psi
#2 175psi
#3 175psi
#4 174psi
these where dry numbers... I didn't do a wet test
 
Last edited:
ZVOLV said:
If the turbine is soaked black with oil, I would say the dynamic seal is the turbo is blown.

When I go pull junkyard turbos, I make sure the turbine isn't oily. If it is, I don't buy the turbo.

You can always pull the 02 sensor and borescope the turbo. It might be easier, depending on your setup.
Click to expand...
quick update on the turbo oil seal.... i pulled off the intake tubing and removed the down pipe for inspection. I was supprised because i thouht for sure there would be a wet turbine wheel since i have smoke, but it looks completly dry. and the intake side as well.

Dry no oil. by turbojose, on Flickr

Untitled by turbojose, on Flickr
 
It is definitely sounding like a valve seal problem at this point. The fact the compressor is clean inside indicates the shaft seal is not leaking. Some of the cone filters cause the shaft seal to leak. Or, just a dirty air filter in general with cause the shaft seal to leak,
 
2manyturbos said:
It is definitely sounding like a valve seal problem at this point. The fact the compressor is clean inside indicates the shaft seal is not leaking. Some of the cone filters cause the shaft seal to leak. Or, just a dirty air filter in general with cause the shaft seal to leak,
Click to expand...
wow... that's good information. I never thought a dirty or bad filter could cause the shaft to leak.
 
update... so I got the cam carrier off, and inspected all of the valve seals before i removed the springs, and you can see 11 of the 16 valve stem seals riding up high on the valve instead of all the way down where they belong. and after removing the springs, the seals were obviously the wrong ones. they are snug on the valves, but don't stay in place. Damn! i paid a place for a valve job several years ago, and I have been rolling like this for years. thank you all for your help. I'm sure my smoke will be gone once i get all of the seals installed properly.

Untitled by turbojose, on Flickr
Untitled by turbojose, on Flickr
 
You must log in or register to reply here.
Back
Top